1
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Sánchez WN, Driessen AJM, Wilson CAM. Protein targeting to the ER membrane: multiple pathways and shared machinery. Crit Rev Biochem Mol Biol 2025:1-47. [PMID: 40377270 DOI: 10.1080/10409238.2025.2503746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2025] [Revised: 05/04/2025] [Accepted: 05/06/2025] [Indexed: 05/18/2025]
Abstract
The endoplasmic reticulum (ER) serves as a central hub for protein production and sorting in eukaryotic cells, processing approximately one-third of the cellular proteome. Protein targeting to the ER occurs through multiple pathways that operate both during and independent of translation. The classical translation-dependent pathway, mediated by cytosolic factors like signal recognition particle, recognizes signal peptides or transmembrane helices in nascent proteins, while translation-independent mechanisms utilize RNA-based targeting through specific sequence elements and RNA-binding proteins. At the core of these processes lies the Sec61 complex, which undergoes dynamic conformational changes and coordinates with numerous accessory factors to facilitate protein translocation and membrane insertion across and into the endoplasmic reticulum membrane. This review focuses on the molecular mechanisms of protein targeting to the ER, from the initial recognition of targeting signals to the dynamics of the translocation machinery, highlighting recent discoveries that have revealed unprecedented complexity in these cellular trafficking pathways.
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Affiliation(s)
- Wendy N Sánchez
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
- Biochemistry and Molecular Biology Department, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
- Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
| | - Christian A M Wilson
- Biochemistry and Molecular Biology Department, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
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2
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Iwasa Y, Miyata S, Tomita T, Yokota N, Miyauchi M, Mori R, Matsushita S, Suzuki R, Saeki Y, Kawahara H. TanGIBLE: A selective probe for evaluating hydrophobicity-exposed defective proteins in live cells. J Cell Biol 2025; 224:e202109010. [PMID: 39812643 PMCID: PMC11734626 DOI: 10.1083/jcb.202109010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 08/22/2024] [Accepted: 11/26/2024] [Indexed: 01/16/2025] Open
Abstract
The accumulation of defective polypeptides in cells is a major cause of various diseases. However, probing defective proteins is difficult because no currently available method can retrieve unstable defective translational products in a soluble state. To overcome this issue, there is a need for a molecular device specific to structurally defective polypeptides. In this study, we developed an artificial protein architecture comprising tandemly aligned BAG6 Domain I, a minimum substrate recognition platform responsible for protein quality control. This tandem-aligned entity shows enhanced affinity not only for model defective polypeptides but also for endogenous polyubiquitinated proteins, which are sensitive to translational inhibition. Mass-spectrometry analysis with this probe enabled the identification of endogenous defective proteins, including orphaned subunits derived from multiprotein complexes and misassembled transmembrane proteins. This probe is also useful for the real-time visualization of protein foci derived from defective polypeptides in stressed cells. Therefore, this "new molecular trap" is a versatile tool for evaluating currently "invisible" pools of defective polypeptides as tangible entities.
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Affiliation(s)
- Yasuyuki Iwasa
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Sohtaroh Miyata
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Takuya Tomita
- Department of Protein Metabolism, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Naoto Yokota
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Maho Miyauchi
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Ruka Mori
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Shin Matsushita
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Rigel Suzuki
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
| | - Yasushi Saeki
- Department of Protein Metabolism, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Kawahara
- Department of Biological Sciences, Laboratory of Cell Biology and Biochemistry, Tokyo Metropolitan University, Tokyo, Japan
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3
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Xu X, Bell TW, Le T, Zhao I, Walker E, Wang Y, Xu N, Soleimanpour SA, Russ HA, Qi L, Tsai B, Liu M, Arvan P. Role of Sec61α2 Translocon in Insulin Biosynthesis. Diabetes 2024; 73:2034-2044. [PMID: 39325584 PMCID: PMC11579409 DOI: 10.2337/db24-0115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 09/17/2024] [Indexed: 09/28/2024]
Abstract
Translocational regulation of proinsulin biosynthesis in pancreatic β-cells is unknown, although several studies have reported an important accessory role for the Translocon-Associated Protein complex to assist preproinsulin delivery into the endoplasmic reticulum via the heterotrimeric Sec61 translocon (comprising α, β, and γ subunits). The actual protein-conducting channel is the α-subunit encoded either by Sec61A1 or its paralog Sec61A2. Although the underlying channel selectivity for preproinsulin translocation is unknown, almost all studies of Sec61α to date have focused on Sec61α1. There is currently no evidence to suggest that this gene product plays a major role in proinsulin production, whereas genome-wide association studies indicate linkage of Sec61A2 with diabetes. Here, we report that evolutionary differences in mouse preproinsulin signal peptides affect proinsulin biosynthesis. Moreover, we find that, although some preproinsulin translocation can proceed through Sec61α1, Sec61α2 has a greater impact on proinsulin biosynthesis in pancreatic β-cells. Remarkably, Sec61α2 translocon deficiency exerts a significant inhibitory effect on the biosynthesis of preproinsulin itself, including a disproportionate increase of full-length nascent chain unreleased from ribosomes. This study not only reveals novel translocational regulation of proinsulin biosynthesis but also provides a rationale for genetic evidence suggesting an important role of Sec61α2 in maintaining blood glucose homeostasis. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Xiaoxi Xu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | | | - Truc Le
- Department of Chemistry, University of Nevada, Reno, NV
| | - Ivy Zhao
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Emily Walker
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Yiqing Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ning Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Scott A. Soleimanpour
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Holger A. Russ
- Diabetes Institute, University of Florida College of Medicine, Gainesville, FL
| | - Ling Qi
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
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4
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Guo J, Yang Y, Xu N, Li X, Yang Y, Feng W, Ye Y, Xu X, Cui J, Liu M, Huang Y. Pancreatic β-Cell TRAPδ Deficiency Reduces Insulin Production but Improves Insulin Sensitivity. Diabetes 2024; 73:1848-1861. [PMID: 39167635 DOI: 10.2337/db23-0984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 08/15/2024] [Indexed: 08/23/2024]
Abstract
The translocon-associated protein-δ (TRAPδ) plays a role in insulin biosynthesis within pancreatic β-cells. However, its pathophysiological significance in maintaining islet β-cell function and glucose homeostasis remains unclear. In this study, we generated a mouse model featuring pancreatic β-cell-specific deletion of TRAPδ (TRAPδ βKO). Our findings revealed that TRAPδ βKO resulted in decreased circulating insulin levels in mice fed either a normal chow diet or a high-fat diet. Multiple independent experiments established that although TRAPδ deletion reduced insulin content in the islets, it had no discernible effect on insulin gene expression, the insulin to proinsulin ratio, or the expression and glycosylation of the prohormone enzymes involved in proinsulin processing. These data suggest that TRAPδ does not play a pivotal role in the transcription of the insulin gene or proinsulin processing. However, untranslocated preproinsulin levels were significantly increased when islets were treated with a proteasomal inhibitor, suggesting that TRAPδ deficiency may hinder preproinsulin translocation, resulting in a rapid degradation of untranslocated preproinsulin that accounts for the decreased insulin production. Remarkably, despite the moderate decrease in circulating insulin levels in TRAPδ βKO mice, their glucose levels remained unaffected, indicating the presence of compensatory mechanisms that help maintain glucose homeostasis. Insulin tolerance tests further revealed improved insulin sensitivity, accompanied by upregulation of phosphorylated AKT in the peripheral tissues of TRAPδ βKO mice. Collectively, these data highlight the important role of TRAPδ in insulin biosynthesis and β-cell function. The moderate reduction in circulating insulin appears to promote insulin sensitivity in insulin target tissues. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Jiyun Guo
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yanshu Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ning Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ying Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yuanyuan Ye
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
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5
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Robeson L, Casanova‐Morales N, Burgos‐Bravo F, Alfaro‐Valdés HM, Lesch R, Ramírez‐Álvarez C, Valdivia‐Delgado M, Vega M, Matute RA, Schekman R, Wilson CAM. Characterization of the interaction between the Sec61 translocon complex and ppαF using optical tweezers. Protein Sci 2024; 33:e4996. [PMID: 38747383 PMCID: PMC11094780 DOI: 10.1002/pro.4996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 05/19/2024]
Abstract
The Sec61 translocon allows the translocation of secretory preproteins from the cytosol to the endoplasmic reticulum lumen during polypeptide biosynthesis. These proteins possess an N-terminal signal peptide (SP) which docks at the translocon. SP mutations can abolish translocation and cause diseases, suggesting an essential role for this SP/Sec61 interaction. However, a detailed biophysical characterization of this binding is still missing. Here, optical tweezers force spectroscopy was used to characterize the kinetic parameters of the dissociation process between Sec61 and the SP of prepro-alpha-factor. The unbinding parameters including off-rate constant and distance to the transition state were obtained by fitting rupture force data to Dudko-Hummer-Szabo models. Interestingly, the translocation inhibitor mycolactone increases the off-rate and accelerates the SP/Sec61 dissociation, while also weakening the interaction. Whereas the translocation deficient mutant containing a single point mutation in the SP abolished the specificity of the SP/Sec61 binding, resulting in an unstable interaction. In conclusion, we characterize quantitatively the dissociation process between the signal peptide and the translocon, and how the unbinding parameters are modified by a translocation inhibitor.
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Affiliation(s)
- Luka Robeson
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
| | - Nathalie Casanova‐Morales
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
- Facultad de Artes LiberalesUniversidad Adolfo IbáñezSantiagoChile
| | - Francesca Burgos‐Bravo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
- California Institute for Quantitative Biosciences, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Hilda M. Alfaro‐Valdés
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
| | - Robert Lesch
- Department of Molecular and Cellular Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Carolina Ramírez‐Álvarez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
| | - Mauricio Valdivia‐Delgado
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
| | - Marcela Vega
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
| | - Ricardo A. Matute
- Centro Integrativo de Biología y Química Aplicada (CIBQA)Universidad Bernardo O'HigginsSantiagoChile
- Division of Chemistry and Chemical EngineeringCalifornia Institute of TechnologyPasadenaCaliforniaUSA
| | - Randy Schekman
- Department of Molecular and Cellular Biology, Howard Hughes Medical InstituteUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Christian A. M. Wilson
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y FarmacéuticasUniversidad de ChileSantiagoChile
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6
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Miller SC, Tikhonova EB, Hernandez SM, Dufour JM, Karamyshev AL. Loss of Preproinsulin Interaction with Signal Recognition Particle Activates Protein Quality Control, Decreasing mRNA Stability. J Mol Biol 2024; 436:168492. [PMID: 38360088 PMCID: PMC11675392 DOI: 10.1016/j.jmb.2024.168492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 01/21/2024] [Accepted: 02/09/2024] [Indexed: 02/17/2024]
Abstract
Many insulin gene variants alter the protein sequence and result in monogenic diabetes due to insulin insufficiency. However, the molecular mechanisms of various disease-causing mutations are unknown. Insulin is synthesized as preproinsulin containing a signal peptide (SP). SPs of secreted proteins are recognized by the signal recognition particle (SRP) or by another factor in a SRP-independent pathway. If preproinsulin uses SRP-dependent or independent pathways is still debatable. We demonstrate by the use of site-specific photocrosslinking that the SRP subunit, SRP54, interacts with the preproinsulin SP. Moreover, SRP54 depletion leads to the decrease of insulin mRNA and protein expression, supporting the involvement of the RAPP protein quality control in insulin biogenesis. RAPP regulates the quality of secretory proteins through degradation of their mRNA. We tested five disease-causing mutations in the preproinsulin SP on recognition by SRP and on their effects on mRNA and protein levels. We demonstrate that the effects of mutations are associated with their position in the SP and their severity. The data support diverse molecular mechanisms involved in the pathogenesis of these mutations. We show for the first time the involvement of the RAPP protein quality control pathway in insulin biogenesis that is implicated in the development of neonatal diabetes caused by the Leu13Arg mutation.
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Affiliation(s)
- Sarah C Miller
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Elena B Tikhonova
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Sarah M Hernandez
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Jannette M Dufour
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Andrey L Karamyshev
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA.
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7
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Mun SH, Hwang CS. Marchf6: A guardian against cytosol-spilled POMC-induced ferroptosis. Mol Cells 2024; 47:100008. [PMID: 38215826 PMCID: PMC10960111 DOI: 10.1016/j.mocell.2024.100008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/02/2024] [Indexed: 01/14/2024] Open
Affiliation(s)
- Sang-Hyeon Mun
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea.
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8
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Vaňková M, Vejražková D, Lukášová P, Včelák J, Chocholová D, Bendlová B. Age-Related Changes in Proinsulin Processing in Normoglycemic Individuals. Physiol Res 2023; 72:S389-S397. [PMID: 38116775 DOI: 10.33549/physiolres.935181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024] Open
Abstract
In order to understand the pathological changes associated with glucose homeostasis in old age, it is necessary to know the natural changes in the processing of proinsulin to mature insulin. While there is abundant information about insulin production and function in diabetics, the situation in healthy adults and the elderly has surprisingly rarely been investigated. The aim of the study was to determine how proinsulin secretion changes in individuals with normal glucose tolerance during the process of natural aging. A total of 761 individuals (539 women, 222 men) aged 18-90 years with normal fasting glycemia (less than 5.6 mmol/l) were divided into five groups according to age. Body composition and levels of fasting blood glucose, proinsulin, insulin, and C-peptide were determined, and the ratios of proinsulin to both insulin and C-peptide were calculated. The homeostasis model of ?-cell function (HOMA F) and peripheral insulin resistance (HOMA R) were calculated. The effect of age was assessed using an ANOVA model consisting of the factors sex, age, and sex × age interaction. Statgraphics Centurion v. XVIII statistical software was used. Glycemia, insulin, C-peptide and HOMA R increased in both sexes up to 75 years. On the contrary, proinsulin levels as well as proinsulin/insulin and proinsulin/C-peptide ratios decreased with age up to 75 years. In normoglycemic and normotolerant people, both women and men, the aging process is associated with decreased insulin sensitivity compensated by potentiation of insulin production. In older age, there is also a gradual decrease in circulating proinsulin, which can be explained by its more efficient processing into active insulin by matured healthy beta cells.
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Affiliation(s)
- M Vaňková
- Institute of Endocrinology, Prague, Czech Republic, Faculty of Science, Charles University, Prague, Czech Republic
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9
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Gutierrez Guarnizo SA, Kellogg MK, Miller SC, Tikhonova E, Karamysheva ZN, Karamyshev AL. Pathogenic signal peptide variants in the human genome. NAR Genom Bioinform 2023; 5:lqad093. [PMID: 37859801 PMCID: PMC10583284 DOI: 10.1093/nargab/lqad093] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/05/2023] [Accepted: 09/29/2023] [Indexed: 10/21/2023] Open
Abstract
Secreted and membrane proteins represent a third of all cellular proteins and contain N-terminal signal peptides that are required for protein targeting to endoplasmic reticulum (ER). Mutations in signal peptides affect protein targeting, translocation, processing, and stability, and are associated with human diseases. However, only a few of them have been identified or characterized. In this report, we identified pathogenic signal peptide variants across the human genome using bioinformatic analyses and predicted the molecular mechanisms of their pathology. We recovered more than 65 thousand signal peptide mutations, over 11 thousand we classified as pathogenic, and proposed framework for distinction of their molecular mechanisms. The pathogenic mutations affect over 3.3 thousand genes coding for secreted and membrane proteins. Most pathogenic mutations alter the signal peptide hydrophobic core, a critical recognition region for the signal recognition particle, potentially activating the Regulation of Aberrant Protein Production (RAPP) quality control and specific mRNA degradation. The remaining pathogenic variants (about 25%) alter either the N-terminal region or signal peptidase processing site that can result in translocation deficiencies at the ER membrane or inhibit protein processing. This work provides a conceptual framework for the identification of mutations across the genome and their connection with human disease.
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Affiliation(s)
| | - Morgana K Kellogg
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Sarah C Miller
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Elena B Tikhonova
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | | | - Andrey L Karamyshev
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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10
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Mun SH, Lee CS, Kim HJ, Kim J, Lee H, Yang J, Im SH, Kim JH, Seong JK, Hwang CS. Marchf6 E3 ubiquitin ligase critically regulates endoplasmic reticulum stress, ferroptosis, and metabolic homeostasis in POMC neurons. Cell Rep 2023; 42:112746. [PMID: 37421621 DOI: 10.1016/j.celrep.2023.112746] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/18/2023] [Accepted: 06/19/2023] [Indexed: 07/10/2023] Open
Abstract
The metabolic prohormone pro-opiomelanocortin (POMC) is generally translocated into the endoplasmic reticulum (ER) for entry into the secretory pathway. Patients with mutations within the signal peptide (SP) of POMC or its adjoining segment develop metabolic disorders. However, the existence, metabolic fate, and functional outcomes of cytosol-retained POMC remain unclear. Here, we show that SP-uncleaved POMC is produced in the cytosol of POMC neuronal cells, thus inducing ER stress and ferroptotic cell death. Mechanistically, the cytosol-retained POMC sequesters the chaperone Hspa5 and subsequently accelerates degradation of the glutathione peroxidase Gpx4, a core regulator of ferroptosis, via the chaperone-mediated autophagy. We also show that the Marchf6 E3 ubiquitin ligase mediates the degradation of cytosol-retained POMC, thereby preventing ER stress and ferroptosis. Furthermore, POMC-Cre-mediated Marchf6-deficient mice exhibit hyperphagia, reduced energy expenditure, and weight gain. These findings suggest that Marchf6 is a critical regulator of ER stress, ferroptosis, and metabolic homeostasis in POMC neurons.
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Affiliation(s)
- Sang-Hyeon Mun
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Chang-Seok Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Hyun Jin Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Jiye Kim
- Korea Mouse Phenotyping Center, Seoul National University, Seoul 08826, South Korea; Laboratory of Developmental Biology and Genomics, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, College of Veterinary Medicine, Seoul National University, Seoul 08826, South Korea; Interdisciplinary Program for Bioinformatics, Program for Cancer Biology and BIO-MAX/N-Bio Institute, Seoul National University, Seoul 08826, South Korea
| | - Haena Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Jihye Yang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
| | - Sin-Hyeog Im
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea; Institute of Convergence Science, Yonsei University, Seoul 03722, South Korea; ImmunoBiome, Inc, Pohang 37666, Republic of Korea
| | - Joung-Hun Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea; Institute of Convergence Science, Yonsei University, Seoul 03722, South Korea
| | - Je Kyung Seong
- Korea Mouse Phenotyping Center, Seoul National University, Seoul 08826, South Korea; Laboratory of Developmental Biology and Genomics, Research Institute for Veterinary Science, and BK21 PLUS Program for Creative Veterinary Science Research, College of Veterinary Medicine, Seoul National University, Seoul 08826, South Korea; Interdisciplinary Program for Bioinformatics, Program for Cancer Biology and BIO-MAX/N-Bio Institute, Seoul National University, Seoul 08826, South Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Korea University, Seoul 02841, South Korea.
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11
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Xu X, Arunagiri A, Alam M, Haataja L, Evans CR, Zhao I, Castro-Gutierrez R, Russ HA, Demangel C, Qi L, Tsai B, Liu M, Arvan P. Nutrient-dependent regulation of β-cell proinsulin content. J Biol Chem 2023; 299:104836. [PMID: 37209827 PMCID: PMC10302188 DOI: 10.1016/j.jbc.2023.104836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/27/2023] [Accepted: 04/30/2023] [Indexed: 05/22/2023] Open
Abstract
Insulin is made from proinsulin, but the extent to which fasting/feeding controls the homeostatically regulated proinsulin pool in pancreatic β-cells remains largely unknown. Here, we first examined β-cell lines (INS1E and Min6, which proliferate slowly and are routinely fed fresh medium every 2-3 days) and found that the proinsulin pool size responds to each feeding within 1 to 2 h, affected both by the quantity of fresh nutrients and the frequency with which they are provided. We observed no effect of nutrient feeding on the overall rate of proinsulin turnover as quantified from cycloheximide-chase experiments. We show that nutrient feeding is primarily linked to rapid dephosphorylation of translation initiation factor eIF2α, presaging increased proinsulin levels (and thereafter, insulin levels), followed by its rephosphorylation during the ensuing hours that correspond to a fall in proinsulin levels. The decline of proinsulin levels is blunted by the integrated stress response inhibitor, ISRIB, or by inhibition of eIF2α rephosphorylation with a general control nonderepressible 2 (not PERK) kinase inhibitor. In addition, we demonstrate that amino acids contribute importantly to the proinsulin pool; mass spectrometry shows that β-cells avidly consume extracellular glutamine, serine, and cysteine. Finally, we show that in both rodent and human pancreatic islets, fresh nutrient availability dynamically increases preproinsulin, which can be quantified without pulse-labeling. Thus, the proinsulin available for insulin biosynthesis is rhythmically controlled by fasting/feeding cycles.
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Affiliation(s)
- Xiaoxi Xu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Maroof Alam
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Charles R Evans
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ivy Zhao
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Roberto Castro-Gutierrez
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, Florida, USA; Diabetes Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Holger A Russ
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, Florida, USA; Diabetes Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Caroline Demangel
- Immunobiology and Therapy Unit, Institut Pasteur, Inserm U1224, Université Paris Cité, Paris, France
| | - Ling Qi
- Departments of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Billy Tsai
- Departments of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA; Departments of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
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12
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Urbanczyk M, Jeyagaran A, Zbinden A, Lu CE, Marzi J, Kuhlburger L, Nahnsen S, Layland SL, Duffy G, Schenke-Layland K. Decorin improves human pancreatic β-cell function and regulates ECM expression in vitro. Matrix Biol 2023; 115:160-183. [PMID: 36592738 DOI: 10.1016/j.matbio.2022.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/01/2023]
Abstract
Transplantation of islets of Langerhans is a promising alternative treatment strategy in severe cases of type 1 diabetes mellitus; however, the success rate is limited by the survival rate of the cells post-transplantation. Restoration of the native pancreatic niche during transplantation potentially can help to improve cell viability and function. Here, we assessed for the first time the regulatory role of the small leucine-rich proteoglycan decorin (DCN) in insulin secretion in human β-cells, and its impact on pancreatic extracellular matrix (ECM) protein expression in vitro. In depth analyses utilizing next-generation sequencing as well as Raman microspectroscopy and Raman imaging identified pathways related to glucose metabolism to be upregulated in DCN-treated cells, including oxidative phosphorylation within the mitochondria as well as proteins and lipids of the endoplasmic reticulum. We further showed the effectiveness of DCN in a transplantation setting by treating collagen type 1-encapsulated β-cell-containing pseudo-islets with DCN. Taken together, in this study, we demonstrate the potential of DCN to improve the function of insulin-secreting β-cells while reducing the expression of ECM proteins affiliated with fibrotic capsule formation, making DCN a highly promising therapeutic agent for islet transplantation.
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Affiliation(s)
- Max Urbanczyk
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany
| | - Abiramy Jeyagaran
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Aline Zbinden
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; Department of Immunology, Leiden University Medical Center Leiden, ZA 2333, the Netherlands
| | - Chuan-En Lu
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany
| | - Julia Marzi
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University Tübingen, Tübingen, Germany
| | - Laurence Kuhlburger
- Quantitative Biology Center (QBiC), Eberhard Karls University of Tübingen, Tübingen, Germany; Biomedical Data Science, Department of Computer Science, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Sven Nahnsen
- Quantitative Biology Center (QBiC), Eberhard Karls University of Tübingen, Tübingen, Germany; Biomedical Data Science, Department of Computer Science, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Shannon L Layland
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; Department of Women's Health, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Garry Duffy
- Discipline of Anatomy and the Regenerative Medicine Institute, School of Medicine, College of Medicine Nursing and Health Sciences, National University of Ireland Galway, Ireland; Science Foundation Ireland (SFI) Centre for Research in Advanced Materials for Biomedical Engineering (AMBER), Trinity College Dublin & National University of Ireland Galway, Galway, Ireland
| | - Katja Schenke-Layland
- Institute of Biomedical Engineering, Department for Medical Technologies and Regenerative Medicine, Eberhard Karls University Tübingen, Silcherstr. 7/1, Tübingen 72076, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University Tübingen, Tübingen, Germany.
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13
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Espinoza MF, Nguyen KK, Sycks MM, Lyu Z, Quanrud GM, Montoya MR, Genereux JC. Heat shock protein Hspa13 regulates endoplasmic reticulum and cytosolic proteostasis through modulation of protein translocation. J Biol Chem 2022; 298:102597. [PMID: 36244454 PMCID: PMC9691929 DOI: 10.1016/j.jbc.2022.102597] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/29/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
Most eukaryotic secretory proteins are cotranslationally translocated through Sec61 into the endoplasmic reticulum (ER). Because these proteins have evolved to fold in the ER, their mistargeting is associated with toxicity. Genetic experiments have implicated the ER heat shock protein 70 (Hsp70) Hspa13/STCH as involved in processing of nascent secretory proteins. Herein, we evaluate the role of Hspa13 in protein import and the maintenance of cellular proteostasis in human cells, primarily using the human embryonic kidney 293T cell line. We find that Hspa13 interacts primarily with the Sec61 translocon and its associated factors. Hspa13 overexpression inhibits translocation of the secreted protein transthyretin, leading to accumulation and aggregation of immature transthyretin in the cytosol. ATPase-inactive mutants of Hspa13 further inhibit translocation and maturation of secretory proteins. While Hspa13 overexpression inhibits cell growth and ER quality control, we demonstrate that HSPA13 knockout destabilizes proteostasis and increases sensitivity to ER disruption. Thus, we propose that Hspa13 regulates import through the translocon to maintain both ER and cytosolic protein homeostasis. The raw mass spectrometry data associated with this article have been deposited in the PRIDE archive and can be accessed at PXD033498.
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Affiliation(s)
- Mateo F Espinoza
- Graduate Program in Microbiology, University of California, Riverside, California, USA
| | - Khanh K Nguyen
- Department of Chemistry, University of California, Riverside, California, USA
| | - Melody M Sycks
- Department of Chemistry, University of California, Riverside, California, USA
| | - Ziqi Lyu
- Department of Chemistry, University of California, Riverside, California, USA
| | - Guy M Quanrud
- Department of Chemistry, University of California, Riverside, California, USA
| | - Maureen R Montoya
- Department of Chemistry, University of California, Riverside, California, USA
| | - Joseph C Genereux
- Graduate Program in Microbiology, University of California, Riverside, California, USA; Department of Chemistry, University of California, Riverside, California, USA.
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14
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Abstract
Insulin secretion is regulated in multiple steps, and one of the main steps is in the endoplasmic reticulum (ER). Here, we show that UDP-glucose induces proinsulin ubiquitination by cereblon, and uridine binds and competes for proinsulin degradation and behaves as sustainable insulin secretagogue. Using insulin mutagenesis of neonatal diabetes variant-C43G and maturity-onset diabetes of the young 10 (MODY10) variant-R46Q, UDP-glucose:glycoprotein glucosyltransferase 1 (UGGT1) protects cereblon-dependent proinsulin ubiquitination in the ER. Cereblon is a ligand-inducible E3 ubiquitin ligase, and we found that UDP-glucose is the first identified endogenous proinsulin protein degrader. Uridine-containing compounds, such as uridine, UMP, UTP, and UDP-galactose, inhibit cereblon-dependent proinsulin degradation and stimulate insulin secretion from 3 to 24 h after administration in β-cell lines as well as mice. This late and long-term insulin secretion stimulation is designated a day sustainable insulin secretion stimulation. Uridine-containing compounds are designated as proinsulin degradation regulators.
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15
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Xu X, Arunagiri A, Haataja L, Alam M, Ji S, Qi L, Tsai B, Liu M, Arvan P. Proteasomal degradation of wild-type proinsulin in pancreatic beta cells. J Biol Chem 2022; 298:102406. [PMID: 35988641 PMCID: PMC9486123 DOI: 10.1016/j.jbc.2022.102406] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 11/22/2022] Open
Abstract
Preproinsulin entry into the endoplasmic reticulum yields proinsulin, and its subsequent delivery to the distal secretory pathway leads to processing, storage, and secretion of mature insulin. Multiple groups have reported that treatment of pancreatic beta cell lines, rodent pancreatic islets, or human islets with proteasome inhibitors leads to diminished proinsulin and insulin protein levels, diminished glucose-stimulated insulin secretion, and changes in beta-cell gene expression that ultimately lead to beta-cell death. However, these studies have mostly examined treatment times far beyond that needed to achieve acute proteasomal inhibition. Here, we report that although proteasomal inhibition immediately downregulates new proinsulin biosynthesis, it nevertheless acutely increases beta-cell proinsulin levels in pancreatic beta cell lines, rodent pancreatic islets, and human islets, indicating rescue of a pool of recently synthesized WT INS gene product that would otherwise be routed to proteasomal disposal. Our pharmacological evidence suggests that this disposal most likely reflects ongoing endoplasmic reticulum–associated protein degradation. However, we found that within 60 min after proteasomal inhibition, intracellular proinsulin levels begin to fall in conjunction with increased phosphorylation of eukaryotic initiation factor 2 alpha, which can be inhibited by blocking the general control nonderepressible 2 kinase. Together, these data demonstrate that a meaningful subfraction of newly synthesized INS gene product undergoes rapid proteasomal disposal. We propose that free amino acids derived from proteasomal proteolysis may potentially participate in suppressing general control nonderepressible 2 kinase activity to maintain ongoing proinsulin biosynthesis.
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Affiliation(s)
- Xiaoxi Xu
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
| | - Anoop Arunagiri
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Leena Haataja
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Maroof Alam
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105
| | - Shuhui Ji
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
| | - Ling Qi
- Departments of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Billy Tsai
- Departments of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052.
| | - Peter Arvan
- The Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI 48105.
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16
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Lyu Z, Sycks MM, Espinoza MF, Nguyen KK, Montoya MR, Galapate CM, Mei L, Genereux JC. Monitoring Protein Import into the Endoplasmic Reticulum in Living Cells with Proximity Labeling. ACS Chem Biol 2022; 17:1963-1977. [PMID: 35675579 DOI: 10.1021/acschembio.2c00405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The proper trafficking of eukaryotic proteins is essential to cellular function. Genetic, environmental, and other stresses can induce protein mistargeting and, in turn, threaten cellular protein homeostasis. Current methods for measuring protein mistargeting are difficult to translate to living cells, and thus the role of cellular signaling networks in stress-dependent protein mistargeting processes, such as ER pre-emptive quality control (ER pQC), is difficult to parse. Herein, we use genetically encoded peroxidases to characterize protein import into the endoplasmic reticulum (ER). We show that the ERHRP/cytAPEX pair provides good selectivity and sensitivity for both multiplexed protein labeling and for identifying protein mistargeting, using the known ER pQC substrate transthyretin (TTR). Although ERHRP labeling induces formation of detergent-resistant TTR aggregates, this is minimized by using low ERHRP expression, without loss of labeling efficiency. cytAPEX labeling recovers TTR that is mistargeted as a consequence of Sec61 inhibition or ER stress-induced ER pQC. Furthermore, we discover that stress-free activation of the ER stress-associated transcription factor ATF6 recapitulates the TTR import deficiency of ER pQC. Hence, proximity labeling is an effective strategy for characterizing factors that influence ER protein import in living cells.
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Affiliation(s)
- Ziqi Lyu
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Melody M Sycks
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Mateo F Espinoza
- Graduate Program of Microbiology, University of California, Riverside, California 92521, United States
| | - Khanh K Nguyen
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Maureen R Montoya
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Cheska M Galapate
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Liangyong Mei
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Joseph C Genereux
- Department of Chemistry, University of California, Riverside, California 92521, United States.,Graduate Program of Microbiology, University of California, Riverside, California 92521, United States
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17
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Lang S, Nguyen D, Bhadra P, Jung M, Helms V, Zimmermann R. Signal Peptide Features Determining the Substrate Specificities of Targeting and Translocation Components in Human ER Protein Import. Front Physiol 2022; 13:833540. [PMID: 35899032 PMCID: PMC9309488 DOI: 10.3389/fphys.2022.833540] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 05/17/2022] [Indexed: 12/11/2022] Open
Abstract
In human cells, approximately 30% of all polypeptides enter the secretory pathway at the level of the endoplasmic reticulum (ER). This process involves cleavable amino-terminal signal peptides (SPs) or more or less amino-terminal transmembrane helices (TMHs), which serve as targeting determinants, at the level of the precursor polypeptides and a multitude of cytosolic and ER proteins, which facilitate their ER import. Alone or in combination SPs and TMHs guarantee the initial ER targeting as well as the subsequent membrane integration or translocation. Cytosolic SRP and SR, its receptor in the ER membrane, mediate cotranslational targeting of most nascent precursor polypeptide chains to the polypeptide-conducting Sec61 complex in the ER membrane. Alternatively, fully-synthesized precursor polypeptides and certain nascent precursor polypeptides are targeted to the ER membrane by either the PEX-, SND-, or TRC-pathway. Although these targeting pathways may have overlapping functions, the question arises how relevant this is under cellular conditions and which features of SPs and precursor polypeptides determine preference for a certain pathway. Irrespective of their targeting pathway(s), most precursor polypeptides are integrated into or translocated across the ER membrane via the Sec61 channel. For some precursor polypeptides specific Sec61 interaction partners have to support the gating of the channel to the open state, again raising the question why and when this is the case. Recent progress shed light on the client spectrum and specificities of some auxiliary components, including Sec62/Sec63, TRAM1 protein, and TRAP. To address the question which precursors use a certain pathway or component in intact human cells, i.e., under conditions of fast translation rates and molecular crowding, in the presence of competing precursors, different targeting organelles, and relevant stoichiometries of the involved components, siRNA-mediated depletion of single targeting or transport components in HeLa cells was combined with label-free quantitative proteomics and differential protein abundance analysis. Here, we present a summary of the experimental approach as well as the resulting differential protein abundance analyses and discuss their mechanistic implications in light of the available structural data.
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Affiliation(s)
- Sven Lang
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Duy Nguyen
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Pratiti Bhadra
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Martin Jung
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
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18
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Zhao LP, Skyler J, Papadopoulos GK, Pugliese A, Najera JA, Bondinas GP, Moustakas AK, Wang R, Pyo CW, Nelson WC, Geraghty DE, Lernmark Å. Association of HLA-DQ Heterodimer Residues -18β and β57 With Progression From Islet Autoimmunity to Diabetes in the Diabetes Prevention Trial-Type 1. Diabetes Care 2022; 45:1610-1620. [PMID: 35621697 PMCID: PMC9274226 DOI: 10.2337/dc21-1628] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 03/07/2022] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The purpose was to test the hypothesis that the HLA-DQαβ heterodimer structure is related to the progression of islet autoimmunity from asymptomatic to symptomatic type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS Next-generation targeted sequencing was used to genotype HLA-DQA1-B1 class II genes in 670 subjects in the Diabetes Prevention Trial-Type 1 (DPT-1). Coding sequences were translated into DQ α- and β-chain amino acid residues and used in hierarchically organized haplotype (HOH) association analysis to identify motifs associated with diabetes onset. RESULTS The opposite diabetes risks were confirmed for HLA DQA1*03:01-B1*03:02 (hazard ratio [HR] 1.36; P = 2.01 ∗ 10-3) and DQA1*03:03-B1*03:01 (HR 0.62; P = 0.037). The HOH analysis uncovered residue -18β in the signal peptide and β57 in the β-chain to form six motifs. DQ*VA was associated with faster (HR 1.49; P = 6.36 ∗ 10-4) and DQ*AD with slower (HR 0.64; P = 0.020) progression to diabetes onset. VA/VA, representing DQA1*03:01-B1*03:02 (DQ8/8), had a greater HR of 1.98 (P = 2.80 ∗ 10-3). The DQ*VA motif was associated with both islet cell antibodies (P = 0.023) and insulin autoantibodies (IAAs) (P = 3.34 ∗ 10-3), while the DQ*AD motif was associated with a decreased IAA frequency (P = 0.015). Subjects with DQ*VA and DQ*AD experienced, respectively, increasing and decreasing trends of HbA1c levels throughout the follow-up. CONCLUSIONS HLA-DQ structural motifs appear to modulate progression from islet autoimmunity to diabetes among at-risk relatives with islet autoantibodies. Residue -18β within the signal peptide may be related to levels of protein synthesis and β57 to stability of the peptide-DQab trimolecular complex.
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Affiliation(s)
- Lue Ping Zhao
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA.,School of Public Health, University of Washington, Seattle, WA
| | - Jay Skyler
- Diabetes Research Institute and Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, FL
| | - George K Papadopoulos
- Laboratory of Biophysics, Biochemistry, Biomaterials and Bioprocessing, Faculty of Agricultural Technology, Technological Educational Institute of Epirus, Arta, Greece
| | - Alberto Pugliese
- Diabetes Research Institute and Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, FL
| | | | - George P Bondinas
- Department of Food Science and Technology, Faculty of Environmental Sciences, Ionian University, Argostoli, Kefalonia, Greece
| | - Antonis K Moustakas
- Department of Food Science and Technology, Faculty of Environmental Sciences, Ionian University, Argostoli, Kefalonia, Greece
| | - Ruihan Wang
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Chul-Woo Pyo
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Wyatt C Nelson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Daniel E Geraghty
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Åke Lernmark
- Department of Clinical Sciences, Lund University Clinical Research Centre, Skåne University Hospital, Malmö, Sweden
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19
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Yang Y, Glidden MD, Dhayalan B, Zaykov AN, Chen YS, Wickramasinghe NP, DiMarchi RD, Weiss MA. Peptide Model of the Mutant Proinsulin Syndrome. II. Nascent Structure and Biological Implications. Front Endocrinol (Lausanne) 2022; 13:821091. [PMID: 35299958 PMCID: PMC8922542 DOI: 10.3389/fendo.2022.821091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
Toxic misfolding of proinsulin variants in β-cells defines a monogenic diabetes syndrome, designated mutant INS-gene induced diabetes of the young (MIDY). In our first study (previous article in this issue), we described a one-disulfide peptide model of a proinsulin folding intermediate and its use to study such variants. The mutations (LeuB15→Pro, LeuA16→Pro, and PheB24→Ser) probe residues conserved among vertebrate insulins. In this companion study, we describe 1H and 1H-13C NMR studies of the peptides; key NMR resonance assignments were verified by synthetic 13C-labeling. Parent spectra retain nativelike features in the neighborhood of the single disulfide bridge (cystine B19-A20), including secondary NMR chemical shifts and nonlocal nuclear Overhauser effects. This partial fold engages wild-type side chains LeuB15, LeuA16 and PheB24 at the nexus of nativelike α-helices α1 and α3 (as defined in native proinsulin) and flanking β-strand (residues B24-B26). The variant peptides exhibit successive structural perturbations in order: parent (most organized) > SerB24 >> ProA16 > ProB15 (least organized). The same order pertains to (a) overall α-helix content as probed by circular dichroism, (b) synthetic yields of corresponding three-disulfide insulin analogs, and (c) ER stress induced in cell culture by corresponding mutant proinsulins. These findings suggest that this and related peptide models will provide a general platform for classification of MIDY mutations based on molecular mechanisms by which nascent disulfide pairing is impaired. We propose that the syndrome's variable phenotypic spectrum-onsets ranging from the neonatal period to later in childhood or adolescence-reflects structural features of respective folding intermediates.
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Affiliation(s)
- Yanwu Yang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Michael D. Glidden
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Nalinda P. Wickramasinghe
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | | | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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20
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Xu X, Huang Y, Li X, Arvan P, Liu M. The Role of TRAPγ/SSR3 in Preproinsulin Translocation Into the Endoplasmic Reticulum. Diabetes 2022; 71:440-452. [PMID: 34857543 PMCID: PMC8893945 DOI: 10.2337/db21-0638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022]
Abstract
In the endoplasmic reticulum (ER), the translocation-associated protein complex (TRAP), also called signal sequence receptor (SSR), includes four integral membrane proteins TRAPα/SSR1, TRAPβ/SSR2, and TRAPδ/SSR4 with the bulk of their extramembranous portions primarily in the ER lumen, whereas the extramembranous portion of TRAPγ/SSR3 is primarily cytosolic. Individually diminished expression of either TRAPα/SSR1, TRAPβ/SSR2, or TRAPδ/SSR4 mRNA is known in each case to lower TRAPα/SSR1 protein levels, leading to impaired proinsulin biosynthesis, whereas forced expression of TRAPα/SSR1 at least partially suppresses the proinsulin biosynthetic defect. Here, we report that diminished TRAPγ/SSR3 expression in pancreatic β-cells leaves TRAPα/SSR1 levels unaffected while nevertheless inhibiting cotranslational and posttranslational translocation of preproinsulin into the ER. Crucially, acute exposure to high glucose leads to a rapid upregulation of both TRAPγ/SSR3 and proinsulin protein without change in the respective mRNA levels, as observed in cultured rodent β-cell lines and confirmed in human islets. Strikingly, pancreatic β-cells with suppressed TRAPγ/SSR3 expression are blocked in glucose-dependent upregulation of proinsulin (or insulin) biosynthesis. Most remarkably, overexpression of TRAPγ/SSR3 in control β-cells raises proinsulin levels, even without boosting extracellular glucose. The data suggest the possibility that TRAPγ/SSR3 may fulfill a rate-limiting function in preproinsulin translocation across the ER membrane for proinsulin biosynthesis.
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Affiliation(s)
- Xiaoxi Xu
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI
- Corresponding authors: Peter Arvan, , and Ming Liu,
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Corresponding authors: Peter Arvan, , and Ming Liu,
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21
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Sargin P, Roethle MF, Jia S, Pant T, Ciecko AE, Atkinson SN, Salzman NH, Teng RJ, Chen YG, Cabrera SM, Hessner MJ. Lactiplantibacillus plantarum 299v supplementation modulates β-cell ER stress and antioxidative defense pathways and prevents type 1 diabetes in gluten-free BioBreeding rats. Gut Microbes 2022; 14:2136467. [PMID: 36261888 PMCID: PMC9586621 DOI: 10.1080/19490976.2022.2136467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/23/2022] [Accepted: 10/03/2022] [Indexed: 02/04/2023] Open
Abstract
The increasing incidence of Type 1 diabetes has coincided with the emergence of the low-fiber, high-gluten Western diet and other environmental factors linked to dysbiosis. Since Lactiplantibacillus plantarum 299 v (Lp299v) supplementation improves gut barrier function and reduces systemic inflammation, we studied its effects in spontaneously diabetic DRlyp/lyp rats provided a normal cereal diet (ND) or a gluten-free hydrolyzed casein diet (HCD). All rats provided ND developed diabetes (62.5±7.7 days); combining ND with Lp299v did not improve survival. Diabetes was delayed by HCD (72.2±9.4 days, p = .01) and further delayed by HCD+Lp299v (84.9±14.3 days, p < .001). HCD+Lp299v pups exhibited increased plasma propionate and butyrate levels, which correlated with enriched fecal Bifidobacteriaceae and Clostridiales taxa. Islet transcriptomic and histologic analyses at 40-days of age revealed that rats fed HCD expressed an autophagy profile, while those provided HCD+Lp299v expressed ER-associated protein degradation (ERAD) and antioxidative defense pathways, including Nrf2. Exposing insulinoma cells to propionate and butyrate promoted the antioxidative defense response but did not recapitulate the HCD+Lp299v islet ERAD transcriptomic profile. Here, both diet and microbiota influenced diabetes susceptibility. Moreover, Lp299v supplement modulated antioxidative defense and ER stress responses in β-cells, potentially offering a new therapeutic direction to thwart diabetes progression and preserve insulin secretion.
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Affiliation(s)
- Pinar Sargin
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Mark F. Roethle
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Shuang Jia
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Tarun Pant
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ashley E. Ciecko
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Samantha N. Atkinson
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Nita H. Salzman
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Microbiology & Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Gastroenterology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ru-Jeng Teng
- Department of Pediatrics, Division of Neonatology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Yi-Guang Chen
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Susanne M. Cabrera
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
| | - Martin J. Hessner
- The Max McGee Research Center for Juvenile Diabetes, Children’s Research Institute of Children’s Hospital of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Division of Endocrinology, the Medical College of Wisconsin, Milwaukee, WI, USA
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22
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Huang Y, Xu X, Arvan P, Liu M. Deficient endoplasmic reticulum translocon-associated protein complex limits the biosynthesis of proinsulin and insulin. FASEB J 2021; 35:e21515. [PMID: 33811688 DOI: 10.1096/fj.202002774r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/14/2021] [Accepted: 02/24/2021] [Indexed: 01/22/2023]
Abstract
The conserved endoplasmic reticulum (ER) membrane protein TRAPα (translocon-associated protein, also known as signal sequence receptor 1, SSR1) has been reported to play a critical but unclear role in insulin biosynthesis. TRAPα/SSR1 is one component of a four-protein complex including TRAPβ/SSR2, TRAPγ/SSR3, and TRAPδ/SSR4. The TRAP complex topologically has a small exposure on the cytosolic side of the ER via its TRAPγ/SSR3 subunit, whereas TRAPβ/SSR2 and TRAPδ/SSR4 function along with TRAPα/SSR1 largely on the luminal side of the ER membrane. Here, we have examined pancreatic β-cells with deficient expression of either TRAPβ/SSR2 or TRAPδ/SSR4, which does not perturb mRNA expression levels of other TRAP subunits, or insulin mRNA. However, deficient protein expression of TRAPβ/SSR2 and, to a lesser degree, TRAPδ/SSR4, diminishes the protein levels of other TRAP subunits, concomitant with deficient steady-state levels of proinsulin and insulin. Deficient TRAPβ/SSR2 or TRAPδ/SSR4 is not associated with any apparent defect of exocytotic mechanism but rather by a decreased abundance of the proinsulin and insulin that accompanies glucose-stimulated secretion. Amino acid pulse labeling directly establishes that much of the steady-state deficiency of intracellular proinsulin can be accounted for by diminished proinsulin biosynthesis, observed in a pulse-labeling as short as 5 minutes. The proinsulin and insulin levels in TRAPβ/SSR2 or TRAPδ/SSR4 null mutant β-cells are notably recovered upon re-expression of the missing TRAP subunit, accompanying a rebound of proinsulin biosynthesis. Remarkably, overexpression of TRAPα/SSR1 can also suppress defects in β-cells with diminished expression of TRAPβ/SSR2, strongly suggesting that TRAPβ/SSR2 is needed to support TRAPα/SSR1 function.
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Affiliation(s)
- Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
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23
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Sicking M, Lang S, Bochen F, Roos A, Drenth JPH, Zakaria M, Zimmermann R, Linxweiler M. Complexity and Specificity of Sec61-Channelopathies: Human Diseases Affecting Gating of the Sec61 Complex. Cells 2021; 10:1036. [PMID: 33925740 PMCID: PMC8147068 DOI: 10.3390/cells10051036] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/15/2021] [Accepted: 04/17/2021] [Indexed: 12/14/2022] Open
Abstract
The rough endoplasmic reticulum (ER) of nucleated human cells has crucial functions in protein biogenesis, calcium (Ca2+) homeostasis, and signal transduction. Among the roughly one hundred components, which are involved in protein import and protein folding or assembly, two components stand out: The Sec61 complex and BiP. The Sec61 complex in the ER membrane represents the major entry point for precursor polypeptides into the membrane or lumen of the ER and provides a conduit for Ca2+ ions from the ER lumen to the cytosol. The second component, the Hsp70-type molecular chaperone immunoglobulin heavy chain binding protein, short BiP, plays central roles in protein folding and assembly (hence its name), protein import, cellular Ca2+ homeostasis, and various intracellular signal transduction pathways. For the purpose of this review, we focus on these two components, their relevant allosteric effectors and on the question of how their respective functional cycles are linked in order to reconcile the apparently contradictory features of the ER membrane, selective permeability for precursor polypeptides, and impermeability for Ca2+. The key issues are that the Sec61 complex exists in two conformations: An open and a closed state that are in a dynamic equilibrium with each other, and that BiP contributes to its gating in both directions in cooperation with different co-chaperones. While the open Sec61 complex forms an aqueous polypeptide-conducting- and transiently Ca2+-permeable channel, the closed complex is impermeable even to Ca2+. Therefore, we discuss the human hereditary and tumor diseases that are linked to Sec61 channel gating, termed Sec61-channelopathies, as disturbances of selective polypeptide-impermeability and/or aberrant Ca2+-permeability.
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Affiliation(s)
- Mark Sicking
- Department of Medical Biochemistry & Molecular Biology, Saarland University, D-66421 Homburg, Germany;
| | - Sven Lang
- Department of Medical Biochemistry & Molecular Biology, Saarland University, D-66421 Homburg, Germany;
| | - Florian Bochen
- Department of Otorhinolaryngology, Head and Neck Surgery, Saarland University Medical Center, D-66421 Homburg, Germany; (F.B.); (M.L.)
| | - Andreas Roos
- Department of Neuropediatrics, Essen University Hospital, D-45147 Essen, Germany;
| | - Joost P. H. Drenth
- Department of Molecular Gastroenterology and Hepatology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands;
| | - Muhammad Zakaria
- Department of Genetics, Hazara University, Mansehra 21300, Pakistan;
| | - Richard Zimmermann
- Department of Medical Biochemistry & Molecular Biology, Saarland University, D-66421 Homburg, Germany;
| | - Maximilian Linxweiler
- Department of Otorhinolaryngology, Head and Neck Surgery, Saarland University Medical Center, D-66421 Homburg, Germany; (F.B.); (M.L.)
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24
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Lemmer IL, Willemsen N, Hilal N, Bartelt A. A guide to understanding endoplasmic reticulum stress in metabolic disorders. Mol Metab 2021; 47:101169. [PMID: 33484951 PMCID: PMC7887651 DOI: 10.1016/j.molmet.2021.101169] [Citation(s) in RCA: 190] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The global rise of metabolic disorders, such as obesity, type 2 diabetes, and cardiovascular disease, demands a thorough molecular understanding of the cellular mechanisms that govern health or disease. The endoplasmic reticulum (ER) is a key organelle for cellular function and metabolic adaptation and, therefore disturbed ER function, known as "ER stress," is a key feature of metabolic disorders. SCOPE OF REVIEW As ER stress remains a poorly defined phenomenon, this review provides a general guide to understanding the nature, etiology, and consequences of ER stress in metabolic disorders. We define ER stress by its type of stressor, which is driven by proteotoxicity, lipotoxicity, and/or glucotoxicity. We discuss the implications of ER stress in metabolic disorders by reviewing evidence implicating ER phenotypes and organelle communication, protein quality control, calcium homeostasis, lipid and carbohydrate metabolism, and inflammation as key mechanisms in the development of ER stress and metabolic dysfunction. MAJOR CONCLUSIONS In mammalian biology, ER is a phenotypically and functionally diverse platform for nutrient sensing, which is critical for cell type-specific metabolic control by hepatocytes, adipocytes, muscle cells, and neurons. In these cells, ER stress is a distinct, transient state of functional imbalance, which is usually resolved by the activation of adaptive programs such as the unfolded protein response (UPR), ER-associated protein degradation (ERAD), or autophagy. However, challenges to proteostasis also impact lipid and glucose metabolism and vice versa. In the ER, sensing and adaptive measures are integrated and failure of the ER to adapt leads to aberrant metabolism, organelle dysfunction, insulin resistance, and inflammation. In conclusion, the ER is intricately linked to a wide spectrum of cellular functions and is a critical component in maintaining and restoring metabolic health.
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Affiliation(s)
- Imke L Lemmer
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Nienke Willemsen
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Nazia Hilal
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Alexander Bartelt
- Institute for Cardiovascular Prevention (IPEK), Pettenkoferstr. 9, Ludwig-Maximilians-University, 80336 Munich, Germany; Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Technische Universität München, Biedersteiner Str. 29, 80802 München, Germany; Department of Molecular Metabolism, 665 Huntington Avenue, Harvard T.H. Chan School of Public Health, 02115 Boston, MA, USA.
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25
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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26
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Yang Y, Shu H, Hu J, Li L, Wang J, Chen T, Zhen J, Sun J, Feng W, Xiong Y, Huang Y, Li X, Zhang K, Fan Z, Guo H, Liu M. A Novel Nonsense INS Mutation Causes Inefficient Preproinsulin Translocation Into the Endoplasmic Reticulum. Front Endocrinol (Lausanne) 2021; 12:774634. [PMID: 35069438 PMCID: PMC8769375 DOI: 10.3389/fendo.2021.774634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Preproinsulin (PPI) translocation across the membrane of the endoplasmic reticulum (ER) is the first and critical step of insulin biosynthesis. Inefficient PPI translocation caused by signal peptide (SP) mutations can lead to β-cell failure and diabetes. However, the effect of proinsulin domain on the efficiency of PPI translocation remains unknown. With whole exome sequencing, we identified a novel INS nonsense mutation resulting in an early termination at the 46th residue of PPI (PPI-R46X) in two unrelated patients with early-onset diabetes. We examined biological behaviors of the mutant and compared them to that of an established neonatal diabetes causing mutant PPI-C96Y. Although both mutants were retained in the cells, unlike C96Y, R46X did not induce ER stress or form abnormal disulfide-linked proinsulin complexes. More importantly, R46X did not interact with co-expressed wild-type (WT) proinsulin in the ER, and did not impair proinsulin-WT folding, trafficking, and insulin production. Metabolic labeling experiments established that, despite with an intact SP, R46X failed to be efficiently translocated into the ER, suggesting that proinsulin domain downstream of SP plays an important unrecognized role in PPI translocation across the ER membrane. The study not only expends the list of INS mutations associated with diabetes, but also provides genetic and biological evidence underlying the regulation mechanism of PPI translocation.
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Affiliation(s)
- Ying Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingxin Hu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Lei Li
- Department of Endocrinology, The Second Part of Jilin University First Hospital, Jilin, China
| | - Jianyu Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Tingting Chen
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinyang Zhen
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yi Xiong
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Kai Zhang
- Department of Technology Services, RSR Tianjin Biotech Co., Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, The Second Hospital of Tianjin Medical University, Tianjin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
| | - Hui Guo
- Department of Endocrinology, The Second Part of Jilin University First Hospital, Jilin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
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27
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Bilekova S, Sachs S, Lickert H. Pharmacological Targeting of Endoplasmic Reticulum Stress in Pancreatic Beta Cells. Trends Pharmacol Sci 2020; 42:85-95. [PMID: 33353789 DOI: 10.1016/j.tips.2020.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 02/06/2023]
Abstract
Diabetes is a disease with pandemic dimensions and no pharmacological treatment prevents disease progression. Dedifferentiation has been proposed to be a driver of beta-cell dysfunction in both type 1 and type 2 diabetes. Regenerative therapies aim to re-establish function in dysfunctional or dedifferentiated beta cells and restore the defective insulin secretion. Unsustainable levels of insulin production, with increased demand at disease onset, strain the beta-cell secretory machinery, leading to endoplasmic reticulum (ER) stress. Unresolved chronic ER stress is a major contributor to beta-cell loss of function and identity. Restoring ER homeostasis, enhancing ER-associated degradation of misfolded protein, and boosting chaperoning activity, are emerging therapeutic approaches for diabetes treatment.
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Affiliation(s)
- Sara Bilekova
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany
| | - Stephan Sachs
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, Neuherberg, Germany.
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28
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Wang H, Saint-Martin C, Xu J, Ding L, Wang R, Feng W, Liu M, Shu H, Fan Z, Haataja L, Arvan P, Bellanné-Chantelot C, Cui J, Huang Y. Biological behaviors of mutant proinsulin contribute to the phenotypic spectrum of diabetes associated with insulin gene mutations. Mol Cell Endocrinol 2020; 518:111025. [PMID: 32916194 PMCID: PMC7734662 DOI: 10.1016/j.mce.2020.111025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023]
Abstract
Insulin gene mutation is the second most common cause of neonatal diabetes (NDM). It is also one of the genes involved in maturity-onset diabetes of the young (MODY). We aim to investigate molecular behaviors of different INS gene variants that may correlate with the clinical spectrum of diabetes phenotypes. In this study, we concentrated on two previously uncharacterized MODY-causing mutants, proinsulin-p.Gly44Arg [G(B20)R] and p.Pro52Leu [P(B28)L] (a novel mutant identified in one French family), and an NDM causing proinsulin-p.(Cys96Tyr) [C(A7)Y]. We find that these proinsulin mutants exhibit impaired oxidative folding in the endoplasmic reticulum (ER) with blocked ER export, ER stress, and apoptosis. Importantly, the proinsulin mutants formed abnormal intermolecular disulfide bonds that not only involved the mutant proinsulin, but also the co-expressed WT-proinsulin, forming misfolded disulfide-linked proinsulin complexes. This impaired the intracellular trafficking of WT-proinsulin and limited the production of bioactive mature insulin. Notably, although all three mutants presented with similar defects in folding, trafficking, and dominant negative behavior, the degrees of these defects appeared to be different. Specifically, compared to MODY mutants G(B20)R and P(B28)L that partially affected folding and trafficking of co-expressed WT-proinsulin, the NDM mutant C(A7)Y resulted in an almost complete blockade of the ER export of WT-proinsulin, decreasing insulin production, inducing more severe ER stress and apoptosis. We thus demonstrate that differences in cell biological behaviors among different proinsulin mutants correlate with the spectrum of diabetes phenotypes caused by the different INS gene mutations.
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Affiliation(s)
- Heting Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Cécile Saint-Martin
- Department of Genetics, Sorbonne University, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ruodan Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China; Tianjin Institute of Endocrinology, Tianjin, China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christine Bellanné-Chantelot
- Department of Genetics, Sorbonne University, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.
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29
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Arneth B. Insulin gene mutations and posttranslational and translocation defects: associations with diabetes. Endocrine 2020; 70:488-497. [PMID: 32656694 DOI: 10.1007/s12020-020-02413-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 07/01/2020] [Indexed: 02/06/2023]
Abstract
The mechanism underlying the pathogenesis of diabetes is complex and poorly understood. Recent investigations have revealed that insulin gene mutations can lead to the development of specific subtypes of diabetes. This systematic review aimed to explore the associations of insulin gene mutations and insulin translocation defects with diabetes. This review was generated using articles from PsycINFO, PubMed, Web of Science, and CINAHL. Search terms and phrases such as "diabetes," "mutations," "insulin," "preproinsulin," "INS gene," "role," "VNTR polymorphisms," and "INS promotor" were used to identify articles relevant to the research topic. The gathered data showed the significant role of insulin gene mutations and insulin translocation defects during diabetes development and progression. Genetic changes can adversely affect the development of various types of diabetes, such as neonatal diabetes mellitus and MIDY. Genetic alterations can affect insulin production, thus compromising the regulation of glucose utilization by tissues. Targeting insulin gene mutations is a potential new avenue for diagnosing and managing diabetes. There are specific subcategories of diabetes, such as MIDY and neonatal diabetes mellitus, caused by insulin gene mutations and defects in posttranslational modification. Further investigations are needed to examine the diagnostic and therapeutic potential of mutation-based biomarkers.
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Affiliation(s)
- Borros Arneth
- Institute of Laboratory Medicine and Pathobiochemistry, Molecular Diagnostics, University Hospital of Giessen and Marburg (UKGM), Justus Liebig University Giessen, Feulgenstr 12, 35332, Giessen, Germany.
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Vasiljević J, Torkko JM, Knoch KP, Solimena M. The making of insulin in health and disease. Diabetologia 2020; 63:1981-1989. [PMID: 32894308 PMCID: PMC7476993 DOI: 10.1007/s00125-020-05192-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/28/2020] [Indexed: 12/16/2022]
Abstract
The discovery of insulin in 1921 has been one of greatest scientific achievements of the 20th century. Since then, the availability of insulin has shifted the focus of diabetes treatment from trying to keep patients alive to saving and improving the life of millions. Throughout this time, basic and clinical research has advanced our understanding of insulin synthesis and action, both in healthy and pathological conditions. Yet, multiple aspects of insulin production remain unknown. In this review, we focus on the most recent findings on insulin synthesis, highlighting their relevance in diabetes. Graphical abstract.
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Affiliation(s)
- Jovana Vasiljević
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Juha M Torkko
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Klaus-Peter Knoch
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Michele Solimena
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany.
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Tatzberg 47/49, 01307, Dresden, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany.
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Živná M, Kidd K, Zaidan M, Vyleťal P, Barešová V, Hodaňová K, Sovová J, Hartmannová H, Votruba M, Trešlová H, Jedličková I, Sikora J, Hůlková H, Robins V, Hnízda A, Živný J, Papagregoriou G, Mesnard L, Beck BB, Wenzel A, Tory K, Häeffner K, Wolf MTF, Bleyer ME, Sayer JA, Ong ACM, Balogh L, Jakubowska A, Łaszkiewicz A, Clissold R, Shaw-Smith C, Munshi R, Haws RM, Izzi C, Capelli I, Santostefano M, Graziano C, Scolari F, Sussman A, Trachtman H, Decramer S, Matignon M, Grimbert P, Shoemaker LR, Stavrou C, Abdelwahed M, Belghith N, Sinclair M, Claes K, Kopel T, Moe S, Deltas C, Knebelmann B, Rampoldi L, Kmoch S, Bleyer AJ. An international cohort study of autosomal dominant tubulointerstitial kidney disease due to REN mutations identifies distinct clinical subtypes. Kidney Int 2020; 98:1589-1604. [PMID: 32750457 DOI: 10.1016/j.kint.2020.06.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 01/05/2023]
Abstract
There have been few clinical or scientific reports of autosomal dominant tubulointerstitial kidney disease due to REN mutations (ADTKD-REN), limiting characterization. To further study this, we formed an international cohort characterizing 111 individuals from 30 families with both clinical and laboratory findings. Sixty-nine individuals had a REN mutation in the signal peptide region (signal group), 27 in the prosegment (prosegment group), and 15 in the mature renin peptide (mature group). Signal group patients were most severely affected, presenting at a mean age of 19.7 years, with the prosegment group presenting at 22.4 years, and the mature group at 37 years. Anemia was present in childhood in 91% in the signal group, 69% prosegment, and none of the mature group. REN signal peptide mutations reduced hydrophobicity of the signal peptide, which is necessary for recognition and translocation across the endoplasmic reticulum, leading to aberrant delivery of preprorenin into the cytoplasm. REN mutations in the prosegment led to deposition of prorenin and renin in the endoplasmic reticulum-Golgi intermediate compartment and decreased prorenin secretion. Mutations in mature renin led to deposition of the mutant prorenin in the endoplasmic reticulum, similar to patients with ADTKD-UMOD, with a rate of progression to end stage kidney disease (63.6 years) that was significantly slower vs. the signal (53.1 years) and prosegment groups (50.8 years) (significant hazard ratio 0.367). Thus, clinical and laboratory studies revealed subtypes of ADTKD-REN that are pathophysiologically, diagnostically, and clinically distinct.
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Affiliation(s)
- Martina Živná
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kendrah Kidd
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic; Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Mohamad Zaidan
- Service de Néphrologie‒Transplantation, Hôpital de Bicêtre, Le Kremlin Bicêtre, France
| | - Petr Vyleťal
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Veronika Barešová
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kateřina Hodaňová
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jana Sovová
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Hana Hartmannová
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Miroslav Votruba
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Helena Trešlová
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Ivana Jedličková
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jakub Sikora
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Helena Hůlková
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Victoria Robins
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Aleš Hnízda
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jan Živný
- Institute of Pathophysiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Gregory Papagregoriou
- Center of Excellence in Biobanking and Biomedical Research, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
| | - Laurent Mesnard
- Sorbonne Université, Urgences Néphrologiques et Transplantation Rénale, Assistance Publique-Hôpitaux de Paris (APHP), Hôpital Tenon, Paris, France
| | - Bodo B Beck
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute of Human Genetics, Cologne, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, Center for Molecular Medicine Cologne (CMMC) and Center for Rare Diseases Cologneies(ZSEK), Cologne, Germany
| | - Andrea Wenzel
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute of Human Genetics, Cologne, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, Center for Molecular Medicine Cologne (CMMC) and Center for Rare Diseases Cologneies(ZSEK), Cologne, Germany
| | - Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Semmelweis University, Budapest, Hungary; First Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Karsten Häeffner
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, Faculty of Medicine, Universitätsklinikum Freiburg, Freiburg, Germany
| | - Matthias T F Wolf
- Pediatric Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michael E Bleyer
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - John A Sayer
- Renal Services, The Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK; NIHR Newcastle Biomedical Research Centre, Newcastle University, Newcastle upon Tyne, UK
| | - Albert C M Ong
- Kidney Genetics Group, Academic Nephrology Unit, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, UK
| | - Lídia Balogh
- First Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Anna Jakubowska
- Department of Pediatric Nephrology Medical University Wrocław, Poland
| | - Agnieszka Łaszkiewicz
- Laboratory of Molecular and Cellular Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Rhian Clissold
- Exeter Kidney Unit, Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Charles Shaw-Smith
- Exeter Kidney Unit, Royal Devon and Exeter NHS Foundation Trust, Exeter, Devon, UK
| | - Raj Munshi
- Division of Nephrology, Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington, USA
| | - Robert M Haws
- Pediatrics-Nephrology, Marshfield Medical Center, Marshfield, Wisconsin, USA
| | - Claudia Izzi
- Division of Nephrology and Dialysis, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia and Montichiari Hospital, Brescia, Italy
| | - Irene Capelli
- Department of Experimental Diagnostic and Specialty Medicine, Nephrology, Dialysis and Renal Transplant Unit, S. Orsola Hospital, University of Bologna, Bologna, Italy
| | | | - Claudio Graziano
- Medical Genetics Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - Francesco Scolari
- Division of Nephrology and Dialysis, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia and Montichiari Hospital, Brescia, Italy
| | - Amy Sussman
- Department of Medicine, Division of Nephrology, University of Arizona Health Sciences Center, Tucson, Arizona, USA
| | - Howard Trachtman
- Division of Nephrology, Department of Pediatrics, New York University School of Medicine, New York, New York, USA
| | - Stephane Decramer
- Pediatric Nephrology, Centre Hospitalier Universitaire de Toulouse (CHU de Toulouse), Toulouse, France; France Rare Renal Disease Reference Centre (SORARE), Toulouse, France; Centre Hospitalier Universitaire de Toulouse (CHU de Toulouse), Toulouse, France
| | - Marie Matignon
- AP-HP (Assistance Publique-Hôpitaux de Paris), Nephrology and Renal Transplantation Department, Institut Francilien de Recherche en Néphrologie et Transplantation (IFRNT), Groupe Hospitalier Henri-Mondor/Albert-Chenevier, Créteil, France; Université Paris-Est-Créteil, (UPEC), DHU (Département Hospitalo-Universitaire) VIC (Virus-Immunité-Cancer), IMRB (Institut Mondor de Recherche Biomédicale), Equipe 21, INSERM U 955, Créteil, France
| | - Philippe Grimbert
- AP-HP (Assistance Publique-Hôpitaux de Paris), Nephrology and Renal Transplantation Department, Institut Francilien de Recherche en Néphrologie et Transplantation (IFRNT), Groupe Hospitalier Henri-Mondor/Albert-Chenevier, Créteil, France; Université Paris-Est-Créteil, (UPEC), DHU (Département Hospitalo-Universitaire) VIC (Virus-Immunité-Cancer), IMRB (Institut Mondor de Recherche Biomédicale), Equipe 21, INSERM U 955, Créteil, France; AP-HP (Assistance Publique-Hôpitaux de Paris), CIC-BT 504, Créteil, France
| | - Lawrence R Shoemaker
- Division of Nephrology, Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | | | - Mayssa Abdelwahed
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of Sfax, Sfax, Tunisia
| | - Neila Belghith
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of Sfax, Sfax, Tunisia; Medical Genetics Department of Hedi Chaker Hospital, Sfax, Tunisia
| | - Matthew Sinclair
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA; Duke Clinical Research Institute, Durham, North Carolina, USA
| | - Kathleen Claes
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium; Laboratory of Nephrology, Department of Microbiology and Immunology, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Tal Kopel
- Nephrology Division, University of Montreal Hospital Centre, Hopital Saint-Luc, Montréal, Québec, Canada
| | - Sharon Moe
- Division of Nephrology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Constantinos Deltas
- Center of Excellence in Biobanking and Biomedical Research, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
| | - Bertrand Knebelmann
- Department of Nephrology‒Transplantation, Necker Hospital, APHP, Paris, France; Paris Descartes University, Sorbonne Paris Cité, Paris, France; Département Biologie cellulaire, INSERM U1151, Institut Necker Enfants Malades, Paris, France
| | - Luca Rampoldi
- Molecular Genetics of Renal Disorders, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Stanislav Kmoch
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic; Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Anthony J Bleyer
- Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic; Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
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Tans R, van Rijswijck DMH, Davidson A, Hannam R, Ricketts B, Tack CJ, Wessels HJCT, Gloerich J, van Gool AJ. Affimers as an alternative to antibodies for protein biomarker enrichment. Protein Expr Purif 2020; 174:105677. [PMID: 32461183 DOI: 10.1016/j.pep.2020.105677] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Assessing the specificity of protein binders is an essential first step in protein biomarker assay development. Affimers are novel protein binders and can potentially replace antibodies in multiple protein capture-based assays. Affimers are selected for their high specificity against the target protein and have benefits over antibodies like batch-to-batch reproducibility and are stable across a wide range of chemical conditions. Here we mimicked a typical initial screening of affimers and commercially available monoclonal antibodies against two non-related proteins, IL-37b and proinsulin, to assess the potential of affimers as alternative to antibodies. METHODS Binding specificity of anti-IL-37b and anti-proinsulin affimers and antibodies was investigated via magnetic bead-based capture of their recombinant protein targets in human plasma. Captured proteins were analyzed using SDS-PAGE, Coomassie blue staining, Western blotting and LC-MS/MS-based proteomics. RESULTS All affimers and antibodies were able to bind their target protein in human plasma. Gel and LC-MS/MS analysis showed that both affimer and antibody-based captures resulted in co-purified background proteins. However, affimer-based captures showed the highest relative enrichment of IL-37b and proinsulin. CONCLUSIONS For both proteins tested, affimers show higher specificity in purifying their target proteins from human plasma compared to monoclonal antibodies. These results indicate that affimers are promising antibody-replacement tools for protein biomarker assay development.
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Affiliation(s)
- Roel Tans
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Danique M H van Rijswijck
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alex Davidson
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Ryan Hannam
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Bryon Ricketts
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Cees J Tack
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Hans J C T Wessels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Jolein Gloerich
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alain J van Gool
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands.
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Identification of Ala2Thr mutation in insulin gene from a Chinese MODY10 family. Mol Cell Biochem 2020; 470:77-86. [PMID: 32405973 DOI: 10.1007/s11010-020-03748-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/06/2020] [Indexed: 12/26/2022]
Abstract
More than 80% of maturity-onset diabetes of the young (MODY) in Chinese is genetically unexplained. To investigate whether the insulin gene (INS) mutation is responsible for some Chinese MODY, we screened INS mutations causing MODY10 in MODY pedigrees and explored the potential pathogenic mechanisms. INS mutations were screened in 56 MODY familial probands. Structure-function characterization and clinical profiling of identified INS mutations were conducted. An INS mutation, at the position 2 alanine-to-threonine substitution (A2T), was identified and co-segregated with hyperglycemia in a MODY pedigree. The A2T mutation converted an α-helix into a β-sheet at the N-terminal of the signal peptide (SP) of preproinsulin. The A2T mutation did not affect preproinsulin translocation across endoplasmic reticulum (ER) membrane, but impaired its SP cleavage within the ER. In INS-1 cells transfected with an A2T mutant, glucose-stimulated insulin secretion (GSIS) was significantly decreased, while BiP luciferase activities were significantly increased compared to that of wild type (WT). We identified an INS-A2T mutation cosegregating with diabetes in a Chinese MODY pedigree. This mutation severely impaired SP cleavage and thus blocked the formation of proinsulin, resulting in enhanced ER stress, which may be responsible for decreased insulin secretion and subsequently, the onset of MODY10.
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Sun J, Xiong Y, Li X, Haataja L, Chen W, Mir SA, Lv L, Madley R, Larkin D, Anjum A, Dhayalan B, Rege N, Wickramasinghe NP, Weiss MA, Itkin-Ansari P, Kaufman RJ, Ostrov DA, Arvan P, Liu M. Role of Proinsulin Self-Association in Mutant INS Gene-Induced Diabetes of Youth. Diabetes 2020; 69:954-964. [PMID: 32139596 PMCID: PMC7171958 DOI: 10.2337/db19-1106] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/22/2020] [Indexed: 02/06/2023]
Abstract
Abnormal interactions between misfolded mutant and wild-type (WT) proinsulin (PI) in the endoplasmic reticulum (ER) drive the molecular pathogenesis of mutant INS gene-induced diabetes of youth (MIDY). How these abnormal interactions are initiated remains unknown. Normally, PI-WT dimerizes in the ER. Here, we suggest that the normal PI-PI contact surface, involving the B-chain, contributes to dominant-negative effects of misfolded MIDY mutants. Specifically, we find that PI B-chain tyrosine-16 (Tyr-B16), which is a key residue in normal PI dimerization, helps confer dominant-negative behavior of MIDY mutant PI-C(A7)Y. Substitutions of Tyr-B16 with either Ala, Asp, or Pro in PI-C(A7)Y decrease the abnormal interactions between the MIDY mutant and PI-WT, rescuing PI-WT export, limiting ER stress, and increasing insulin production in β-cells and human islets. This study reveals the first evidence indicating that noncovalent PI-PI contact initiates dominant-negative behavior of misfolded PI, pointing to a novel therapeutic target to enhance PI-WT export and increase insulin production.
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Affiliation(s)
- Jinhong Sun
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Yi Xiong
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Wei Chen
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Saiful A Mir
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Li Lv
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Rachel Madley
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Dennis Larkin
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Arfah Anjum
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Nischay Rege
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH
| | | | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Pamela Itkin-Ansari
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - David A Ostrov
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Ming Liu
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
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Schorr S, Nguyen D, Haßdenteufel S, Nagaraj N, Cavalié A, Greiner M, Weissgerber P, Loi M, Paton AW, Paton JC, Molinari M, Förster F, Dudek J, Lang S, Helms V, Zimmermann R. Identification of signal peptide features for substrate specificity in human Sec62/Sec63-dependent ER protein import. FEBS J 2020; 287:4612-4640. [PMID: 32133789 DOI: 10.1111/febs.15274] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/22/2020] [Accepted: 03/02/2020] [Indexed: 02/06/2023]
Abstract
In mammalian cells, one-third of all polypeptides are integrated into the membrane or translocated into the lumen of the endoplasmic reticulum (ER) via the Sec61 channel. While the Sec61 complex facilitates ER import of most precursor polypeptides, the Sec61-associated Sec62/Sec63 complex supports ER import in a substrate-specific manner. So far, mainly posttranslationally imported precursors and the two cotranslationally imported precursors of ERj3 and prion protein were found to depend on the Sec62/Sec63 complex in vitro. Therefore, we determined the rules for engagement of Sec62/Sec63 in ER import in intact human cells using a recently established unbiased proteomics approach. In addition to confirming ERj3, we identified 22 novel Sec62/Sec63 substrates under these in vivo-like conditions. As a common feature, those previously unknown substrates share signal peptides (SP) with comparatively longer but less hydrophobic hydrophobic region of SP and lower carboxy-terminal region of SP (C-region) polarity. Further analyses with four substrates, and ERj3 in particular, revealed the combination of a slowly gating SP and a downstream translocation-disruptive positively charged cluster of amino acid residues as decisive for the Sec62/Sec63 requirement. In the case of ERj3, these features were found to be responsible for an additional immunoglobulin heavy-chain binding protein (BiP) requirement and to correlate with sensitivity toward the Sec61-channel inhibitor CAM741. Thus, the human Sec62/Sec63 complex may support Sec61-channel opening for precursor polypeptides with slowly gating SPs by direct interaction with the cytosolic amino-terminal peptide of Sec61α or via recruitment of BiP and its interaction with the ER-lumenal loop 7 of Sec61α. These novel insights into the mechanism of human ER protein import contribute to our understanding of the etiology of SEC63-linked polycystic liver disease. DATABASES: The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository (http://www.ebi.ac.uk/pride/archive/projects/Identifiers) with the dataset identifiers: PXD008178, PXD011993, and PXD012078. Supplementary information was deposited at Mendeley Data (https://data.mendeley.com/datasets/6s5hn73jcv/2).
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Affiliation(s)
- Stefan Schorr
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Duy Nguyen
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Sarah Haßdenteufel
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Nagarjuna Nagaraj
- Core Facility, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Adolfo Cavalié
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Markus Greiner
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Petra Weissgerber
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Marisa Loi
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, University of Adelaide, SA, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, University of Adelaide, SA, Australia
| | - Maurizio Molinari
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | - Friedrich Förster
- Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands
| | - Johanna Dudek
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Sven Lang
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
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36
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Morishita Y, Arvan P. Lessons from animal models of endocrine disorders caused by defects of protein folding in the secretory pathway. Mol Cell Endocrinol 2020; 499:110613. [PMID: 31605742 PMCID: PMC6886696 DOI: 10.1016/j.mce.2019.110613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/26/2019] [Accepted: 10/04/2019] [Indexed: 02/06/2023]
Abstract
Most peptide hormones originate from secretory protein precursors synthesized within the endoplasmic reticulum (ER). In this specialized organelle, the newly-made prohormones must fold to their native state. Completion of prohormone folding usually occurs prior to migration through the secretory pathway, as unfolded/misfolded prohormones are retained by mechanisms collectively known as ER quality control. Not only do most monomeric prohormones need to fold properly, but many also dimerize or oligomerize within the ER. If oligomerization occurs before completion of monomer folding then when a poorly folded peptide prohormone is retained by quality control mechanisms, it may confer ER retention upon its oligomerization partners. Conversely, oligomerization between well-folded and improperly folded partners might help to override ER quality control, resulting in rescue of misfolded forms. Both scenarios appear to be possible in different animal models of endocrine disorders caused by genetic defects of protein folding in the secretory pathway. In this paper, we briefly review three such conditions, including familial neurohypophyseal diabetes insipidus, insulin-deficient diabetes mellitus, and hypothyroidism with defective thyroglobulin.
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Affiliation(s)
- Yoshiaki Morishita
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan.
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan School of Medicine, Brehm Tower Room 5112, 1000, Wall St., Ann Arbor, MI, USA.
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37
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Mao R, Chen Y, Chi Z, Wang Y. Insulin and its single-chain analogue. Appl Microbiol Biotechnol 2019; 103:8737-8751. [PMID: 31637493 DOI: 10.1007/s00253-019-10170-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/02/2019] [Accepted: 10/08/2019] [Indexed: 12/26/2022]
Abstract
Insulin therapy remains the most effective method to treat diabetes mellitus (DM), and the demand for this valuable hormone has exceeded that of any other protein-based medicine as a result of the dramatic increase in the number of diabetic patients worldwide. Understanding the structure of insulin and the interaction with its receptor is important for developing proper formulations. As a result of the relatively low thermal stability of native insulin and its two-chain analogues, the application of single-chain insulin (SCI) analogues, which can be obtained relatively easily by recombinant DNA technology or chemical synthetic methods, represents a promising alternative approach. In this review, the basic knowledge of insulin (discovery, biosynthesis, and structure) and the current model of the interaction with its receptor are outlined. Furthermore, we outline the strategies for the design and production of various SCI analogues and their reported applications.
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Affiliation(s)
- Ruifeng Mao
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, School of Life Science, Huaiyin Normal University, Huai'an, 223300, Jiangsu, China.
| | - Yingying Chen
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, School of Life Science, Huaiyin Normal University, Huai'an, 223300, Jiangsu, China
| | - Zhenjing Chi
- Huai'an First People's Hospital, Nanjing Medical University, Huai'an, 223300, China
| | - Yefu Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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38
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Hegde RS, Zavodszky E. Recognition and Degradation of Mislocalized Proteins in Health and Disease. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033902. [PMID: 30833453 DOI: 10.1101/cshperspect.a033902] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A defining feature of eukaryotic cells is the segregation of complex biochemical processes among different intracellular compartments. The protein targeting, translocation, and trafficking pathways that sustain compartmentalization must recognize a diverse range of clients via degenerate signals. This recognition is imperfect, resulting in polypeptides at incorrect cellular locations. Cells have evolved mechanisms to selectively recognize mislocalized proteins and triage them for degradation or rescue. These spatial quality control pathways maintain cellular protein homeostasis, become especially important during organelle stress, and might contribute to disease when they are impaired or overwhelmed.
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Affiliation(s)
- Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Eszter Zavodszky
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
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39
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Schaeffer C, Izzi C, Vettori A, Pasqualetto E, Cittaro D, Lazarevic D, Caridi G, Gnutti B, Mazza C, Jovine L, Scolari F, Rampoldi L. Autosomal Dominant Tubulointerstitial Kidney Disease with Adult Onset due to a Novel Renin Mutation Mapping in the Mature Protein. Sci Rep 2019; 9:11601. [PMID: 31406136 PMCID: PMC6691008 DOI: 10.1038/s41598-019-48014-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/22/2019] [Indexed: 01/10/2023] Open
Abstract
Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a genetically heterogeneous renal disorder leading to progressive loss of renal function. ADTKD-REN is due to rare mutations in renin, all localized in the protein leader peptide and affecting its co-translational insertion in the endoplasmic reticulum (ER). Through exome sequencing in an adult-onset ADTKD family we identified a new renin variant, p.L381P, mapping in the mature protein. To assess its pathogenicity, we combined genetic data, computational and predictive analysis and functional studies. The L381P substitution affects an evolutionary conserved residue, co-segregates with renal disease, is not found in population databases and is predicted to be deleterious by in silico tools and by structural modelling. Expression of the L381P variant leads to its ER retention and induction of the Unfolded Protein Response in cell models and to defective pronephros development in zebrafish. Our work shows that REN mutations outside of renin leader peptide can cause ADTKD and delineates an adult form of ADTKD-REN, a condition which has usually its onset in childhood. This has implications for the molecular diagnosis and the estimated prevalence of the disease and points at ER homeostasis as a common pathway affected in ADTKD-REN, and possibly more generally in ADTKD.
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Affiliation(s)
- Céline Schaeffer
- Molecular Genetics of Renal Disorders, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Claudia Izzi
- Division of Nephrology and Dialysis, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia and Montichiari Hospital, Brescia, Italy.,Prenatal Diagnosis Unit, Department of Obstetrics and Gynecology, ASST Spedali Civili, Brescia, Italy
| | - Andrea Vettori
- Department of Biology, University of Padova, Padova, Italy.,Department of Biotechnology, University of Verona, Verona, Italy
| | - Elena Pasqualetto
- Molecular Genetics of Renal Disorders, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Davide Cittaro
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Dejan Lazarevic
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Gianluca Caridi
- Laboratory of Molecular Nephrology, Istituto Giannina Gaslini IRCCS, Genoa, Italy
| | - Barbara Gnutti
- Laboratory of Medical Genetics, Department of Pathology, ASST Spedali Civili, Brescia, Italy
| | - Cinzia Mazza
- Laboratory of Medical Genetics, Department of Pathology, ASST Spedali Civili, Brescia, Italy
| | - Luca Jovine
- Department of Biosciences and Nutrition & Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Francesco Scolari
- Division of Nephrology and Dialysis, Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia and Montichiari Hospital, Brescia, Italy
| | - Luca Rampoldi
- Molecular Genetics of Renal Disorders, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
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40
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Zhu R, Li X, Xu J, Barrabi C, Kekulandara D, Woods J, Chen X, Liu M. Defective endoplasmic reticulum export causes proinsulin misfolding in pancreatic β cells. Mol Cell Endocrinol 2019; 493:110470. [PMID: 31158417 PMCID: PMC6613978 DOI: 10.1016/j.mce.2019.110470] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) homeostasis is essential for cell function. Increasing evidence indicates that, efficient protein ER export is important for ER homeostasis. However, the consequence of impaired ER export remains largely unknown. Herein, we found that defective ER protein transport caused by either Sar1 mutants or brefeldin A impaired proinsulin oxidative folding in the ER of β-cells. Misfolded proinsulin formed aberrant disulfide-linked dimers and high molecular weight proinsulin complexes, and induced ER stress. Limiting proinsulin load to the ER alleviated ER stress, indicating that misfolded proinsulin is a direct cause of ER stress. This study revealed significance of efficient ER export in maintaining ER protein homeostasis and native folding of proinsulin. Given the fact that proinsulin misfolding plays an important role in diabetes, this study suggests that enhancing ER export may be a potential therapeutic target to prevent/delay β-cell failure caused by proinsulin misfolding and ER stress.
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Affiliation(s)
- Ruimin Zhu
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Cesar Barrabi
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Dilini Kekulandara
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - James Woods
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA.
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China.
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41
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Liu S, Li X, Yang J, Zhu R, Fan Z, Xu X, Feng W, Cui J, Sun J, Liu M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells. FASEB J 2019; 33:11338-11348. [PMID: 31311313 PMCID: PMC6766638 DOI: 10.1096/fj.201900442r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin resistance in classic insulin-responsive tissues is a hallmark of type 2 diabetes (T2D). However, the pathologic significance of β-cell insulin resistance and the underlying mechanisms contributing to defective insulin signaling in β cells remain largely unknown. Emerging evidence indicates that proinsulin misfolding is not only the molecular basis of mutant INS-gene–induced diabetes of youth (MIDY) but also an important contributor in the development and progression of T2D. However, the molecular basis of β-cell failure caused by misfolded proinsulin is still incompletely understood. Herein, using Akita mice expressing diabetes-causing mutant proinsulin, we found that misfolded proinsulin abnormally interacted with the precursor of insulin receptor (ProIR) in the endoplasmic reticulum (ER), impaired ProIR maturation to insulin receptor (IR), and decreased insulin signaling in β cells. Importantly, using db/db insulin-resistant mice, we found that oversynthesis of proinsulin led to an increased proinsulin misfolding, which resulted in impairments of ProIR processing and insulin signaling in β cells. These results reveal for the first time that misfolded proinsulin can interact with ProIR in the ER, impairing intracellular processing of ProIR and leading to defective insulin signaling that may contribute to β-cell failure in both MIDY and T2D.—Liu, S., Li, X., Yang, J., Zhu, R., Fan, Z., Xu, X., Feng, W., Cui, J., Sun, J., Liu, M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells.
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Affiliation(s)
- Shiqun Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ruimin Zhu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Health Management, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
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42
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Abstract
Most newly synthesized proteins destined for the secretory pathway contain a signal peptide (SP) that triggers cotranslational translocation into the endoplasmic reticulum (ER). However, how small polypeptides undergo ER translocation is not fully understood. In this issue of JBC, Guo et al. describe a mechanism for posttranslational translocation of small secretory proteins featuring a positive charge within the SP N-terminal region. Defects in this element disrupt proper secretion and explain the effects of genetic mutations associated with one type of diabetes.
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Affiliation(s)
- Yukari Okamoto
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607-7170
| | - Sojin Shikano
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607-7170
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43
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Easa N, Alany RG, Carew M, Vangala A. A review of non-invasive insulin delivery systems for diabetes therapy in clinical trials over the past decade. Drug Discov Today 2019; 24:440-451. [DOI: 10.1016/j.drudis.2018.11.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/19/2018] [Accepted: 11/15/2018] [Indexed: 02/08/2023]
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44
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Liu M, Weiss MA, Arunagiri A, Yong J, Rege N, Sun J, Haataja L, Kaufman RJ, Arvan P. Biosynthesis, structure, and folding of the insulin precursor protein. Diabetes Obes Metab 2018; 20 Suppl 2:28-50. [PMID: 30230185 PMCID: PMC6463291 DOI: 10.1111/dom.13378] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Insulin synthesis in pancreatic β-cells is initiated as preproinsulin. Prevailing glucose concentrations, which oscillate pre- and postprandially, exert major dynamic variation in preproinsulin biosynthesis. Accompanying upregulated translation of the insulin precursor includes elements of the endoplasmic reticulum (ER) translocation apparatus linked to successful orientation of the signal peptide, translocation and signal peptide cleavage of preproinsulin-all of which are necessary to initiate the pathway of proper proinsulin folding. Evolutionary pressures on the primary structure of proinsulin itself have preserved the efficiency of folding ("foldability"), and remarkably, these evolutionary pressures are distinct from those protecting the ultimate biological activity of insulin. Proinsulin foldability is manifest in the ER, in which the local environment is designed to assist in the overall load of proinsulin folding and to favour its disulphide bond formation (while limiting misfolding), all of which is closely tuned to ER stress response pathways that have complex (beneficial, as well as potentially damaging) effects on pancreatic β-cells. Proinsulin misfolding may occur as a consequence of exuberant proinsulin biosynthetic load in the ER, proinsulin coding sequence mutations, or genetic predispositions that lead to an altered ER folding environment. Proinsulin misfolding is a phenotype that is very much linked to deficient insulin production and diabetes, as is seen in a variety of contexts: rodent models bearing proinsulin-misfolding mutants, human patients with Mutant INS-gene-induced Diabetes of Youth (MIDY), animal models and human patients bearing mutations in critical ER resident proteins, and, quite possibly, in more common variety type 2 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202 IN USA
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Jing Yong
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Nischay Rege
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
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45
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Millership SJ, Da Silva Xavier G, Choudhury AI, Bertazzo S, Chabosseau P, Pedroni SM, Irvine EE, Montoya A, Faull P, Taylor WR, Kerr-Conte J, Pattou F, Ferrer J, Christian M, John RM, Latreille M, Liu M, Rutter GA, Scott J, Withers DJ. Neuronatin regulates pancreatic β cell insulin content and secretion. J Clin Invest 2018; 128:3369-3381. [PMID: 29864031 PMCID: PMC6063487 DOI: 10.1172/jci120115] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/17/2018] [Indexed: 02/06/2023] Open
Abstract
Neuronatin (Nnat) is an imprinted gene implicated in human obesity and widely expressed in neuroendocrine and metabolic tissues in a hormone- and nutrient-sensitive manner. However, its molecular and cellular functions and precise role in organismal physiology remain only partly defined. Here we demonstrate that mice lacking Nnat globally or specifically in β cells display impaired glucose-stimulated insulin secretion leading to defective glucose handling under conditions of nutrient excess. In contrast, we report no evidence for any feeding or body weight phenotypes in global Nnat-null mice. At the molecular level neuronatin augments insulin signal peptide cleavage by binding to the signal peptidase complex and facilitates translocation of the nascent preprohormone. Loss of neuronatin expression in β cells therefore reduces insulin content and blunts glucose-stimulated insulin secretion. Nnat expression, in turn, is glucose-regulated. This mechanism therefore represents a novel site of nutrient-sensitive control of β cell function and whole-animal glucose homeostasis. These data also suggest a potential wider role for Nnat in the regulation of metabolism through the modulation of peptide processing events.
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Affiliation(s)
- Steven J. Millership
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Gabriela Da Silva Xavier
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | | | - Sergio Bertazzo
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Silvia M.A. Pedroni
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Elaine E. Irvine
- MRC London Institute of Medical Sciences, London, United Kingdom
| | - Alex Montoya
- MRC London Institute of Medical Sciences, London, United Kingdom
| | - Peter Faull
- MRC London Institute of Medical Sciences, London, United Kingdom
| | - William R. Taylor
- Computational Cell and Molecular Biology Laboratory, Francis Crick Institute, London, United Kingdom
| | - Julie Kerr-Conte
- European Genomic Institute for Diabetes, UMR 1190 Translational Research for Diabetes, INSERM, CHU Lille, University of Lille, Lille, France
| | - Francois Pattou
- European Genomic Institute for Diabetes, UMR 1190 Translational Research for Diabetes, INSERM, CHU Lille, University of Lille, Lille, France
| | - Jorge Ferrer
- Beta Cell Genome Regulation Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Mark Christian
- Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Rosalind M. John
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - James Scott
- National Heart and Lung Institute, Department of Medicine, Imperial College London, London, United Kingdom
| | - Dominic J. Withers
- MRC London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
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46
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Abedini A, Derk J, Schmidt AM. The receptor for advanced glycation endproducts is a mediator of toxicity by IAPP and other proteotoxic aggregates: Establishing and exploiting common ground for novel amyloidosis therapies. Protein Sci 2018; 27:1166-1180. [PMID: 29664151 PMCID: PMC6032365 DOI: 10.1002/pro.3425] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 12/23/2022]
Abstract
Proteotoxicity plays a key role in many devastating human disorders, including Alzheimer's, Huntington's and Parkinson's diseases; type 2 diabetes; systemic amyloidosis; and cardiac dysfunction, to name a few. The cellular mechanisms of proteotoxicity in these disorders have been the focus of considerable research, but their role in prevalent and morbid disorders, such as diabetes, is less appreciated. There is a large body of literature on the impact of glucotoxicity and lipotoxicity on insulin-producing pancreatic β-cells, and there is increasing recognition that proteotoxicty plays a key role. Pancreatic islet amyloidosis by the hormone IAPP, the production of advanced glycation endproducts (AGE), and insulin misprocessing into cytotoxic aggregates are all sources of β-cell proteotoxicity in diabetes. AGE, produced by the reaction of reducing sugars with proteins and lipids are ligands for the receptor for AGE (RAGE), as are the toxic pre-fibrillar aggregates of IAPP produced during amyloid formation. The mechanisms of amyloid formation by IAPP in vivo or in vitro are not well understood, and the cellular mechanisms of IAPP-induced β-cell death are not fully defined. Here, we review recent findings that illuminate the factors and mechanisms involved in β-cell proteotoxicity in diabetes. Together, these new insights have far-reaching implications for the establishment of unifying mechanisms by which pathological amyloidoses imbue their injurious effects in vivo.
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Affiliation(s)
- Andisheh Abedini
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
| | - Julia Derk
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
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Guo H, Sun J, Li X, Xiong Y, Wang H, Shu H, Zhu R, Liu Q, Huang Y, Madley R, Wang Y, Cui J, Arvan P, Liu M. Positive charge in the n-region of the signal peptide contributes to efficient post-translational translocation of small secretory preproteins. J Biol Chem 2017; 293:1899-1907. [PMID: 29229776 DOI: 10.1074/jbc.ra117.000922] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 11/30/2017] [Indexed: 12/17/2022] Open
Abstract
Increasing evidence indicates that many small secretory preproteins can undergo post-translational translocation across the membrane of the endoplasmic reticulum. Although the cellular machinery involved in post-translational translocation of small secretory preproteins has begun to be elucidated, the intrinsic signals contained within these small secretory preproteins that contribute to their efficient post-translational translocation remain unknown. Here, we analyzed the eukaryotic secretory proteome and discovered the small secretory preproteins tend to have a higher probability to harbor the positive charge in the n-region of the signal peptide (SP). Eliminating the positive charge of the n-region blocked post-translational translocation of newly synthesized preproteins and selectively impaired translocation efficiency of small secretory preproteins. The pathophysiological significance of the positive charge in the n-region of SP was underscored by recently identified preproinsulin SP mutations that impair translocation of preproinsulin and cause maturity onset diabetes of youth (MODY). Remarkably, we have found that slowing the polypeptide elongation rate of small secretory preproteins could alleviate the translocation defect caused by loss of the n-region positive charge of the signal peptide. Together, these data reveal not only a previously unrecognized role of the n-region's positive charge in ensuring efficient post-translational translocation of small secretory preproteins, but they also highlight the molecular contribution of defects in this process to the pathogenesis of genetic disorders such as MODY.
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Affiliation(s)
- Huan Guo
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China.,the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
| | - Jinhong Sun
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China.,the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
| | - Xin Li
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yi Xiong
- the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
| | - Heting Wang
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Hua Shu
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ruimin Zhu
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Qi Liu
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yumeng Huang
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Rachel Madley
- the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
| | - Yulun Wang
- the Division of Endocrinology, Tianjin People's Hospital, Tianjin 300120, China
| | - Jingqiu Cui
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Peter Arvan
- the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
| | - Ming Liu
- From the Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China, .,the Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, and
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48
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Yang Y, Chan L. Monogenic Diabetes: What It Teaches Us on the Common Forms of Type 1 and Type 2 Diabetes. Endocr Rev 2016; 37:190-222. [PMID: 27035557 PMCID: PMC4890265 DOI: 10.1210/er.2015-1116] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To date, more than 30 genes have been linked to monogenic diabetes. Candidate gene and genome-wide association studies have identified > 50 susceptibility loci for common type 1 diabetes (T1D) and approximately 100 susceptibility loci for type 2 diabetes (T2D). About 1-5% of all cases of diabetes result from single-gene mutations and are called monogenic diabetes. Here, we review the pathophysiological basis of the role of monogenic diabetes genes that have also been found to be associated with common T1D and/or T2D. Variants of approximately one-third of monogenic diabetes genes are associated with T2D, but not T1D. Two of the T2D-associated monogenic diabetes genes-potassium inward-rectifying channel, subfamily J, member 11 (KCNJ11), which controls glucose-stimulated insulin secretion in the β-cell; and peroxisome proliferator-activated receptor γ (PPARG), which impacts multiple tissue targets in relation to inflammation and insulin sensitivity-have been developed as major antidiabetic drug targets. Another monogenic diabetes gene, the preproinsulin gene (INS), is unique in that INS mutations can cause hyperinsulinemia, hyperproinsulinemia, neonatal diabetes mellitus, one type of maturity-onset diabetes of the young (MODY10), and autoantibody-negative T1D. Dominant heterozygous INS mutations are the second most common cause of permanent neonatal diabetes. Moreover, INS gene variants are strongly associated with common T1D (type 1a), but inconsistently with T2D. Variants of the monogenic diabetes gene Gli-similar 3 (GLIS3) are associated with both T1D and T2D. GLIS3 is a key transcription factor in insulin production and β-cell differentiation during embryonic development, which perturbation forms the basis of monogenic diabetes as well as its association with T1D. GLIS3 is also required for compensatory β-cell proliferation in adults; impairment of this function predisposes to T2D. Thus, monogenic forms of diabetes are invaluable "human models" that have contributed to our understanding of the pathophysiological basis of common T1D and T2D.
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Affiliation(s)
- Yisheng Yang
- Division of Endocrinology (Y.Y.), Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109; and Diabetes and Endocrinology Research Center (L.C.), Division of Diabetes, Endocrinology and Metabolism, Departments of Medicine, Molecular and Cellular Biology, Biochemistry and Molecular Biology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Lawrence Chan
- Division of Endocrinology (Y.Y.), Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109; and Diabetes and Endocrinology Research Center (L.C.), Division of Diabetes, Endocrinology and Metabolism, Departments of Medicine, Molecular and Cellular Biology, Biochemistry and Molecular Biology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
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van Lummel M, van Veelen PA, de Ru AH, Janssen GMC, Pool J, Laban S, Joosten AM, Nikolic T, Drijfhout JW, Mearin ML, Aanstoot HJ, Peakman M, Roep BO. Dendritic Cells Guide Islet Autoimmunity through a Restricted and Uniquely Processed Peptidome Presented by High-Risk HLA-DR. THE JOURNAL OF IMMUNOLOGY 2016; 196:3253-63. [PMID: 26944932 DOI: 10.4049/jimmunol.1501282] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 02/02/2016] [Indexed: 12/13/2022]
Abstract
Identifying T cell epitopes of islet autoantigens is important for understanding type 1 diabetes (T1D) immunopathogenesis and to design immune monitoring and intervention strategies in relationship to disease progression. Naturally processed T cell epitopes have been discovered by elution from HLA-DR4 of pulsed B lymphocytes. The designated professional APC directing immune responses is the dendritic cell (DC). To identify naturally processed epitopes, monocyte-derived DC were pulsed with preproinsulin (PPI), glutamic acid decarboxylase (65-kDa isoform; GAD65), and insulinoma-associated Ag-2 (IA-2), and peptides were eluted of HLA-DR3 and -DR4, which are associated with highest risk for T1D development. Proteome analysis confirmed uptake and processing of islet Ags by DC. PPI peptides generated by DC differed from those processed by B lymphocytes; PPI signal-sequence peptides were eluted from HLA-DR4 and -DR3/4 that proved completely identical to a primary target epitope of diabetogenic HLA-A2-restricted CD8 T cells. HLA-DR4 binding was confirmed. GAD65 peptides, eluted from HLA-DR3 and -DR4, encompassed two core regions overlapping the two most immunodominant and frequently studied CD4 T cell targets. GAD65 peptides bound to HLA-DR3. Strikingly, the IA-2 ligandome of HLA-DR was exclusively generated from the extracellular part of IA-2, whereas most previous immune studies have focused on intracellular IA-2 epitopes. The newly identified IA-2 peptides bound to HLA-DR3 and -DR4. Differential T cell responses were detected against the newly identified IA-2 epitopes in blood from T1D patients. The core regions to which DC may draw attention from autoreactive T cells are largely distinct and more restricted than are those of B cells. GAD65 peptides presented by DC focus on highly immunogenic T cell targets, whereas HLA-DR-binding peptides derived from IA-2 are distinct from the target regions of IA-2 autoantibodies.
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Affiliation(s)
- Menno van Lummel
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Peter A van Veelen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Arnoud H de Ru
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - George M C Janssen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Jos Pool
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Sandra Laban
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Antoinette M Joosten
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Tatjana Nikolic
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Jan W Drijfhout
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - M Luisa Mearin
- Department of Pediatrics, Leiden University Medical Center, 2300 RC Leiden, the Netherlands
| | - Henk J Aanstoot
- Diabeter, Center for Pediatric and Adolescent Diabetes Care and Research, 3011 TA Rotterdam, the Netherlands
| | - Mark Peakman
- Department of Immunobiology, School of Medicine, King's College London, London SE1 9RT, United Kingdom; and
| | - Bart O Roep
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, 2300 RC Leiden, the Netherlands; Department of Diabetes Immunology, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010
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50
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van Lummel M, van Veelen PA, de Ru AH, Pool J, Nikolic T, Laban S, Joosten A, Drijfhout JW, Gómez-Touriño I, Arif S, Aanstoot HJ, Peakman M, Roep BO. Discovery of a Selective Islet Peptidome Presented by the Highest-Risk HLA-DQ8trans Molecule. Diabetes 2016; 65:732-41. [PMID: 26718497 DOI: 10.2337/db15-1031] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/17/2015] [Indexed: 11/13/2022]
Abstract
HLA-DQ2/8 heterozygous individuals are at far greater risk for type 1 diabetes (T1D) development by expressing HLA-DQ8trans on antigen-presenting cells compared with HLA-DQ2 or -DQ8 homozygous individuals. Dendritic cells (DC) initiate and shape adaptive immune responses by presenting HLA-epitope complexes to naïve T cells. To dissect the role of HLA-DQ8trans in presenting natural islet epitopes, we analyzed the islet peptidome of HLA-DQ2, -DQ8, and -DQ2/8 by pulsing DC with preproinsulin (PPI), IA-2, and GAD65. Quality and quantity of islet epitopes presented by HLA-DQ2/8 differed from -DQ2 or -DQ8. We identified two PPI epitopes solely processed and presented by HLA-DQ2/8 DC: an HLA-DQ8trans-binding signal-sequence epitope previously identified as CD8 T-cell epitope and a second epitope that we previously identified as CD4 T-cell epitope with increased binding to HLA-DQ8trans upon posttranslational modification. IA-2 epitopes retrieved from HLA-DQ2/8 and -DQ8 DC bound to HLA-DQ8cis/trans. No GAD65 epitopes were eluted from HLA-DQ. T-cell responses were detected against the novel islet epitopes in blood from patients with T1D but scantly detected in healthy donor subjects. We report the first PPI and IA-2 natural epitopes presented by highest-risk HLA-DQ8trans. The selective processing and presentation of HLA-DQ8trans-binding islet epitopes provides insight in the mechanism of excessive genetic risk imposed by HLA-DQ2/8 heterozygosity and may assist immune monitoring of disease progression and therapeutic intervention as well as provide therapeutic targets for immunotherapy in subjects at risk for T1D.
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Affiliation(s)
- Menno van Lummel
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Peter A van Veelen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Arnoud H de Ru
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Jos Pool
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Tatjana Nikolic
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Sandra Laban
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Antoinette Joosten
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan W Drijfhout
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Iria Gómez-Touriño
- Department of Immunobiology, School of Medicine, King's College London, London, U.K
| | - Sefina Arif
- Department of Immunobiology, School of Medicine, King's College London, London, U.K
| | - Henk J Aanstoot
- Diabeter, Center for Pediatric and Adolescent Diabetes Care and Research, Rotterdam, the Netherlands
| | - Mark Peakman
- Department of Immunobiology, School of Medicine, King's College London, London, U.K
| | - Bart O Roep
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands Department of Diabetes Immunology, Diabetes & Metabolism Research Institute at the Beckman Research Institute of City of Hope, Duarte, CA
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