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Park D, Yu Y, Kim JH, Lee J, Park J, Hong K, Seo JK, Lim C, Min KT. Suboptimal Mitochondrial Activity Facilitates Nuclear Heat Shock Responses for Proteostasis and Genome Stability. Mol Cells 2023; 46:374-386. [PMID: 37077029 PMCID: PMC10258458 DOI: 10.14348/molcells.2023.2181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 04/21/2023] Open
Abstract
Thermal stress induces dynamic changes in nuclear proteins and relevant physiology as a part of the heat shock response (HSR). However, how the nuclear HSR is fine-tuned for cellular homeostasis remains elusive. Here, we show that mitochondrial activity plays an important role in nuclear proteostasis and genome stability through two distinct HSR pathways. Mitochondrial ribosomal protein (MRP) depletion enhanced the nucleolar granule formation of HSP70 and ubiquitin during HSR while facilitating the recovery of damaged nuclear proteins and impaired nucleocytoplasmic transport. Treatment of the mitochondrial proton gradient uncoupler masked MRP-depletion effects, implicating oxidative phosphorylation in these nuclear HSRs. On the other hand, MRP depletion and a reactive oxygen species (ROS) scavenger non-additively decreased mitochondrial ROS generation during HSR, thereby protecting the nuclear genome from DNA damage. These results suggest that suboptimal mitochondrial activity sustains nuclear homeostasis under cellular stress, providing plausible evidence for optimal endosymbiotic evolution via mitochondria-to-nuclear communication.
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Affiliation(s)
- Dongkeun Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Youngim Yu
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Ji-hyung Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jongbin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jongmin Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Kido Hong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jeong-Kon Seo
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Kyung-Tai Min
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
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2
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Ghasemi S, Mahdavi M, Maleki M, Salahshourifar I, Kalayinia S. A novel likely pathogenic variant in the FBXO32 gene associated with dilated cardiomyopathy according to whole‑exome sequencing. BMC Med Genomics 2022; 15:234. [PMID: 36344977 PMCID: PMC9641816 DOI: 10.1186/s12920-022-01388-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Background Familial dilated cardiomyopathy (DCM) is a genetic heart disorder characterized by progressive heart failure and sudden cardiac death. Over 250 genes have been reported in association with DCM; nonetheless, the genetic cause of most DCM patients has been unknown. The goal of the present study was to determine the genetic etiology of familial DCM in an Iranian family. Methods Whole-exome sequencing was performed to identify the underlying variants in an Iranian consanguineous family with DCM. The presence of the candidate variant was confirmed and screened in available relatives by PCR and Sanger sequencing. The pathogenic effect of the candidate variant was assessed by bioinformatics analysis, homology modeling, and docking. Results One novel likely pathogenic deletion, c.884_886del: p.Lys295del, in F-box only protein 32 (muscle-specific ubiquitin-E3 ligase protein; FBXO32) was identified. Based on bioinformatics and modeling analysis, c.884_886del was the most probable cause of DCM in the studied family. Conclusions Our findings indicate that variants in FBXO32 play a role in recessive DCM. Variants in FBXO32 may disturb the degradation of target proteins in the ubiquitin–proteasome system and lead to severe DCM. We suggest considering this gene variants in patients with recessively inherited DCM.
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3
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Yang L, Gilbertsen A, Smith K, Xia H, Higgins L, Guerrero C, Henke CA. Proteomic analysis of the IPF mesenchymal progenitor cell nuclear proteome identifies abnormalities in key nodal proteins that underlie their fibrogenic phenotype. Proteomics 2022; 22:e2200018. [PMID: 35633524 PMCID: PMC9541064 DOI: 10.1002/pmic.202200018] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 11/25/2022]
Abstract
IPF is a progressive fibrotic lung disease whose pathogenesis remains incompletely understood. We have previously discovered pathologic mesenchymal progenitor cells (MPCs) in the lungs of IPF patients. IPF MPCs display a distinct transcriptome and create sustained interstitial fibrosis in immune deficient mice. However, the precise pathologic alterations responsible for this fibrotic phenotype remain to be uncovered. Quantitative mass spectrometry and interactomics is a powerful tool that can define protein alterations in specific subcellular compartments that can be implemented to understand disease pathogenesis. We employed quantitative mass spectrometry and interactomics to define protein alterations in the nuclear compartment of IPF MPCs compared to control MPCs. We identified increased nuclear levels of PARP1, CDK1, and BACH1. Interactomics implicated PARP1, CDK1, and BACH1 as key hub proteins in the DNA damage/repair, differentiation, and apoptosis signaling pathways respectively. Loss of function and inhibitor studies demonstrated important roles for PARP1 in DNA damage/repair, CDK1 in regulating IPF MPC stemness and self-renewal, and BACH1 in regulating IPF MPC viability. Our quantitative mass spectrometry studies combined with interactomic analysis uncovered key roles for nuclear PARP1, CDK1, and BACH1 in regulating IPF MPC fibrogenicity.
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Affiliation(s)
- Libang Yang
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Adam Gilbertsen
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Karen Smith
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Hong Xia
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - LeeAnn Higgins
- Center for Mass Spectrometry and ProteomicsUniversity of MinnesotaSt. PaulMinnesotaUSA
| | - Candace Guerrero
- Center for Mass Spectrometry and ProteomicsUniversity of MinnesotaSt. PaulMinnesotaUSA
| | - Craig A. Henke
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesotaUSA
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Yang L, Yang J, Jacobson B, Gilbertsen A, Smith K, Higgins L, Guerrero C, Xia H, Henke CA, Lin J. SFPQ Promotes Lung Cancer Malignancy via Regulation of CD44 v6 Expression. Front Oncol 2022; 12:862250. [PMID: 35707369 PMCID: PMC9190464 DOI: 10.3389/fonc.2022.862250] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
Mesenchymal stem cells (MSCs) contribute to tumor pathogenesis and elicit antitumor immune responses in tumor microenvironments. Nuclear proteins might be the main players in these processes. In the current study, combining spatial proteomics with ingenuity pathway analysis (IPA) in lung non-small cell (NSC) cancer MSCs, we identify a key nuclear protein regulator, SFPQ (Splicing Factor Proline and Glutamine Rich), which is overexpressed in lung cancer MSCs and functions to promote MSCs proliferation, chemical resistance, and invasion. Mechanistically, the knockdown of SFPQ reduces CD44v6 expression to inhibit lung cancer MSCs stemness, proliferation in vitro, and metastasis in vivo. The data indicates that SFPQ may be a potential therapeutic target for limiting growth, chemotherapy resistance, and metastasis of lung cancer.
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Affiliation(s)
- Libang Yang
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Jianbo Yang
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Minneapolis, Minneapolis, MN, United States.,The Cancer Center, Fujian Medical University Union Hospital, Fuzhou, China
| | - Blake Jacobson
- Hematology, Oncology and Transplantation, School of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Adam Gilbertsen
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Karen Smith
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - LeeAnn Higgins
- Center for Mass Spectrometry and Proteomics, University of Minnesota, St. Paul, MN, United States
| | - Candace Guerrero
- Center for Mass Spectrometry and Proteomics, University of Minnesota, St. Paul, MN, United States
| | - Hong Xia
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Craig A Henke
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Jizhen Lin
- The Cancer Center, Fujian Medical University Union Hospital, Fuzhou, China.,The Immunotherapy Research Laboratory, Department of Otolaryngology, Cancer Center, University of Minnesota, Minneapolis, MN, United States
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5
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Soares ES, Prediger RD, Brocardo PS, Cimarosti HI. SUMO-modifying Huntington's disease. IBRO Neurosci Rep 2022; 12:203-209. [PMID: 35746980 PMCID: PMC9210482 DOI: 10.1016/j.ibneur.2022.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/06/2022] [Indexed: 12/25/2022] Open
Abstract
Small ubiquitin-like modifiers, SUMOs, are proteins that are conjugated to target substrates and regulate their functions in a post-translational modification called SUMOylation. In addition to its physiological roles, SUMOylation has been implicated in several neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases (HD). HD is a neurodegenerative monogenetic autosomal dominant disorder caused by a mutation in the CAG repeat of the huntingtin (htt) gene, which expresses a mutant Htt protein more susceptible to aggregation and toxicity. Besides Htt, other SUMO ligases, enzymes, mitochondrial and autophagic components are also important for the progression of the disease. Here we review the main aspects of Htt SUMOylation and its role in cellular processes involved in the pathogenesis of HD.
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Affiliation(s)
- Ericks S. Soares
- Post-graduate Program in Pharmacology, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
| | - Rui D. Prediger
- Post-graduate Program in Pharmacology, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
- Post-graduate Program in Neuroscience, UFSC, Florianópolis, Santa Catarina, Brazil
| | - Patricia S. Brocardo
- Post-graduate Program in Neuroscience, UFSC, Florianópolis, Santa Catarina, Brazil
| | - Helena I. Cimarosti
- Post-graduate Program in Pharmacology, Federal University of Santa Catarina (UFSC), Florianópolis, Santa Catarina, Brazil
- Post-graduate Program in Neuroscience, UFSC, Florianópolis, Santa Catarina, Brazil
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6
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Borgert L, Mishra S, den Brave F. Quality control of cytoplasmic proteins inside the nucleus. Comput Struct Biotechnol J 2022; 20:4618-4625. [PMID: 36090811 PMCID: PMC9440239 DOI: 10.1016/j.csbj.2022.08.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/03/2022] Open
Abstract
A complex network of molecular chaperones and proteolytic machinery safeguards the proteins which comprise the proteome, from the time they are synthesized on ribosomes to their destruction via proteolysis. Impaired protein quality control results in the accumulation of aberrant proteins, which may undergo unwanted spurious interactions with other proteins, thereby interfering with a broad range of cellular functions. To protect the cellular environment, such proteins are degraded or sequestered into inclusions in different subcellular compartments. Recent findings demonstrate that aberrant or mistargeted proteins from different cytoplasmic compartments are removed from their environment by transporting them into the nucleus. These proteins are degraded by the nuclear ubiquitin–proteasome system or sequestered into intra-nuclear inclusions. Here, we discuss the emerging role of the nucleus as a cellular quality compartment based on recent findings in the yeast Saccharomyces cerevisiae. We describe the current knowledge on cytoplasmic substrates of nuclear protein quality control, the mechanism of nuclear import of such proteins, as well as possible advantages and risks of nuclear sequestration of aberrant proteins.
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7
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Kitajima Y, Suzuki N, Yoshioka K, Izumi R, Tateyama M, Tashiro Y, Takahashi R, Aoki M, Ono Y. Inducible Rpt3, a Proteasome Component, Knockout in Adult Skeletal Muscle Results in Muscle Atrophy. Front Cell Dev Biol 2020; 8:859. [PMID: 32984340 PMCID: PMC7492297 DOI: 10.3389/fcell.2020.00859] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/10/2020] [Indexed: 12/21/2022] Open
Abstract
The ubiquitin–proteasome system has the capacity to degrade polyubiquitinated proteins and plays an important role in many cellular processes. However, the role of Rpt3, a crucial proteasomal gene, has not been investigated in adult muscles in vivo. Herein, we generated skeletal-muscle-specific Rpt3 knockout mice, in which genetic inactivation of Rpt3 could be induced by doxycycline administration. The Rpt3-knockout mice showed a significant reduction by more than 90% in the expression of Rpt3 in adult muscles. Using this model, we found that proteasome dysfunction in adult muscles resulted in muscle wasting and a decrease in the myofiber size. Immunoblotting analysis showed that the amounts of ubiquitinated proteins were markedly higher in muscles of Rpt3-deficient mice than in those of the control mice. Analysis of the autophagy pathway in the Rpt3-deficient mice showed that the upregulation of LC3II, p62, Atg5, Atg7, and Beclin-1 in protein levels, which supposed to be compensatory proteolysis activation. Our results suggest that the proteasome inhibition in adult muscle severely deteriorates myofiber integrity and results in muscle atrophy.
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Affiliation(s)
- Yasuo Kitajima
- Department of Muscle Development and Regeneration, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Naoki Suzuki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,Department of Neurology, Shodo-kai Southern Tohoku General Hospital, Iwanuma, Japan
| | - Kiyoshi Yoshioka
- Department of Muscle Development and Regeneration, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Rumiko Izumi
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Maki Tateyama
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,National Hospital Organization Iwate National Hospital, Hanamaki, Japan
| | - Yoshitaka Tashiro
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Yusuke Ono
- Department of Muscle Development and Regeneration, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
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8
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Gvozdenov Z, Kolhe J, Freeman BC. The Nuclear and DNA-Associated Molecular Chaperone Network. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a034009. [PMID: 30745291 PMCID: PMC6771373 DOI: 10.1101/cshperspect.a034009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Maintenance of a healthy and functional proteome in all cellular compartments is critical to cell and organismal homeostasis. Yet, our understanding of the proteostasis process within the nucleus is limited. Here, we discuss the identified roles of the major molecular chaperones Hsp90, Hsp70, and Hsp60 with client proteins working in diverse DNA-associated pathways. The unique challenges facing proteins in the nucleus are considered as well as the conserved features of the molecular chaperone system in facilitating DNA-linked processes. As nuclear protein inclusions are a common feature of protein-aggregation diseases (e.g., neurodegeneration), a better understanding of nuclear proteostasis is warranted.
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Affiliation(s)
- Zlata Gvozdenov
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801.,Department Chemie, Technische Universität München, Garching 85748, Germany
| | - Janhavi Kolhe
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801
| | - Brian C Freeman
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801
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9
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Abstract
This study compares the native structures of cytosolic and nuclear proteasomes, visualized directly within cells. The assembly states and functional states of proteasomes in each compartment were similar, indicating comparable levels of proteolytic activity per proteasome. Nuclear proteasomes were tethered to two different sites at the nuclear pore complex (NPC): the inner nuclear membrane and the NPC basket. Structural analysis revealed mechanistic details of the two tethering interactions. These results present direct evidence that proteasomes bind at NPCs, establishing a cellular hub for protein degradation at the gateway between the nucleus and cytoplasm. This work demonstrates how cryo-electron tomography can reveal biological mechanisms by directly observing the interactions between molecular complexes within the native cellular environment. The partitioning of cellular components between the nucleus and cytoplasm is the defining feature of eukaryotic life. The nuclear pore complex (NPC) selectively gates the transport of macromolecules between these compartments, but it is unknown whether surveillance mechanisms exist to reinforce this function. By leveraging in situ cryo-electron tomography to image the native cellular environment of Chlamydomonas reinhardtii, we observed that nuclear 26S proteasomes crowd around NPCs. Through a combination of subtomogram averaging and nanometer-precision localization, we identified two classes of proteasomes tethered via their Rpn9 subunits to two specific NPC locations: binding sites on the NPC basket that reflect its eightfold symmetry and more abundant binding sites at the inner nuclear membrane that encircle the NPC. These basket-tethered and membrane-tethered proteasomes, which have similar substrate-processing state frequencies as proteasomes elsewhere in the cell, are ideally positioned to regulate transcription and perform quality control of both soluble and membrane proteins transiting the NPC.
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10
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Amanullah A, Upadhyay A, Joshi V, Mishra R, Jana NR, Mishra A. Progressing neurobiological strategies against proteostasis failure: Challenges in neurodegeneration. Prog Neurobiol 2017; 159:1-38. [DOI: 10.1016/j.pneurobio.2017.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 06/01/2017] [Accepted: 08/25/2017] [Indexed: 02/07/2023]
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11
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There Is an Inclusion for That: Material Properties of Protein Granules Provide a Platform for Building Diverse Cellular Functions. Trends Biochem Sci 2017; 42:765-776. [DOI: 10.1016/j.tibs.2017.08.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/26/2017] [Accepted: 08/03/2017] [Indexed: 12/30/2022]
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12
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Zhong Y, Wang J, Henderson MJ, Yang P, Hagen BM, Siddique T, Vogel BE, Deng HX, Fang S. Nuclear export of misfolded SOD1 mediated by a normally buried NES-like sequence reduces proteotoxicity in the nucleus. eLife 2017; 6:e23759. [PMID: 28463106 PMCID: PMC5449186 DOI: 10.7554/elife.23759] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/30/2017] [Indexed: 12/14/2022] Open
Abstract
Over 170 different mutations in the gene encoding SOD1 all cause amyotrophic lateral sclerosis (ALS). Available studies have been primarily focused on the mechanisms underlying mutant SOD1 cytotoxicity. How cells defend against the cytotoxicity remains largely unknown. Here, we show that misfolding of ALS-linked SOD1 mutants and wild-type (wt) SOD1 exposes a normally buried nuclear export signal (NES)-like sequence. The nuclear export carrier protein CRM1 recognizes this NES-like sequence and exports misfolded SOD1 to the cytoplasm. Antibodies against the NES-like sequence recognize misfolded SOD1, but not native wt SOD1 both in vitro and in vivo. Disruption of the NES consensus sequence relocalizes mutant SOD1 to the nucleus, resulting in higher toxicity in cells, and severer impairments in locomotion, egg-laying, and survival in Caenorhabditis elegans. Our data suggest that SOD1 mutants are removed from the nucleus by CRM1 as a defense mechanism against proteotoxicity of misfolded SOD1 in the nucleus.
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Affiliation(s)
- Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, United States
- Department of Physiology, University of Maryland School of Medicine, Baltimore, United States
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Johns Hopkins University, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, United States
| | - Peixin Yang
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, United States
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, United States
| | - Brian M Hagen
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, United States
- Department of Physiology, University of Maryland School of Medicine, Baltimore, United States
| | - Teepu Siddique
- Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Bruce E Vogel
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, United States
- Department of Physiology, University of Maryland School of Medicine, Baltimore, United States
| | - Han-Xiang Deng
- Division of Neuromuscular Medicine, Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, United States
- Department of Physiology, University of Maryland School of Medicine, Baltimore, United States
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, United States
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13
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Sampuda KM, Riley M, Boyd L. Stress induced nuclear granules form in response to accumulation of misfolded proteins in Caenorhabditis elegans. BMC Cell Biol 2017; 18:18. [PMID: 28424053 PMCID: PMC5395811 DOI: 10.1186/s12860-017-0136-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 04/07/2017] [Indexed: 01/30/2023] Open
Abstract
Background Environmental stress can affect the viability or fecundity of an organism. Environmental stressors may affect the genome or the proteome and can cause cellular distress by contributing to protein damage or misfolding. This study examines the cellular response to environmental stress in the germline of the nematode, C. elegans. Results Salt stress, oxidative stress, and starvation, but not heat shock, induce the relocalization of ubiquitin, proteasome, and the TIAR-2 protein into distinct subnuclear regions referred to as stress induced nuclear granules (SINGs). The SINGs form within 1 h of stress initiation and do not require intertissue signaling. K48-linked polyubiquitin chains but not K63 chains are enriched in SINGs. Worms with a mutation in the conjugating enzyme, ubc-18, do not form SINGs. Additionally, knockdown of ubc-20 and ubc-22 reduces the level of SING formation as does knockdown of the ubiquitin ligase chn-1, a CHIP homolog. The nuclear import machinery is required for SING formation. Stressed embryos containing SINGs fail to hatch and cell division in these embryos is halted. The formation of SINGs can be prevented by pre-exposure to a brief period of heat shock before stress exposure. Heat shock inhibition of SINGs is dependent upon the HSF-1 transcription factor. Conclusions The heat shock results suggest that chaperone expression can prevent SING formation and that the accumulation of damaged or misfolded proteins is a necessary precursor to SING formation. Thus, SINGs may be part of a novel protein quality control system. The data suggest an interesting model where SINGs represent sites of localized protein degradation for nuclear or cytosolic proteins. Thus, the physiological impacts of environmental stress may begin at the cellular level with the formation of stress induced nuclear granules. Electronic supplementary material The online version of this article (doi:10.1186/s12860-017-0136-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katherine M Sampuda
- Department of Biology, Middle Tennessee State University, 1301 E. Main Street, Murfreesboro, TN, 37132, USA
| | - Mason Riley
- Department of Biology, Middle Tennessee State University, 1301 E. Main Street, Murfreesboro, TN, 37132, USA
| | - Lynn Boyd
- Department of Biology, Middle Tennessee State University, 1301 E. Main Street, Murfreesboro, TN, 37132, USA.
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14
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Jones L, Goode L, Davila E, Brown A, McCarthy DM, Sharma N, Bhide PG, Armata IA. Translational effects and coding potential of an upstream open reading frame associated with DOPA Responsive Dystonia. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1171-1182. [PMID: 28366877 DOI: 10.1016/j.bbadis.2017.03.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/17/2017] [Accepted: 03/29/2017] [Indexed: 01/08/2023]
Abstract
Upstream open reading frames (uORFs) have emerged as major post-transcriptional regulatory elements in eukaryotic species. In general, uORFs are initiated by a translation start codon within the 5' untranslated region of a gene (upstream ATG; uATG), and they are negatively correlated with translational efficiency. In addition to their translational regulatory role, some uORFs can code for biologically active short peptides. The importance of uATGs/uORFs is further underscored by human diseases associated with single nucleotide polymorphisms (SNPs), which disrupt existing uORFs or introduce novel uORFs. Although several functional proteins translated from naturally occurring uORFs have been described, the coding potential of uORFs created by SNPs has been ignored because of the a priori assumption that these proteins are short-lived with no likely impact on protein homeostasis. Thus, studies on SNP-created uORFs are limited to their translational effects, leaving unexplored the potential cellular consequences of a SNP/uORF-encoded protein. Here, we investigate functionality of a uATG/uORF introduced by a +142C>T SNP within the GCH1 gene and associated with a familial form of DOPA Responsive Dystonia. We report that the +142C>T SNP represses GCH1 translation, and introduces a short, frame shifted uORF that encodes a 73-amino acid peptide. This peptide is localized within the nucleus and compromises cell viability upon proteasome inhibition. Our work extends the list of uATG/uORF associated diseases and advances research on peptides translated from SNP-introduced uORFs, a neglected component of the proteome.
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Affiliation(s)
- Lataisia Jones
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Lacy Goode
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Eduardo Davila
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Amber Brown
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Deirdre M McCarthy
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA
| | - Nutan Sharma
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Pradeep G Bhide
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA.
| | - Ioanna A Armata
- Center for Brain Repair and Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306, USA.
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The Proline/Arginine Dipeptide from Hexanucleotide Repeat Expanded C9ORF72 Inhibits the Proteasome. eNeuro 2017; 4:eN-NWR-0249-16. [PMID: 28197542 PMCID: PMC5282547 DOI: 10.1523/eneuro.0249-16.2017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 01/05/2017] [Accepted: 01/12/2017] [Indexed: 12/11/2022] Open
Abstract
An intronic hexanucleotide repeat expansion (HRE) mutation in the C9ORF72 gene is the most common cause of familial ALS and frontotemporal dementia (FTD) and is found in ∼7% of individuals with apparently sporadic disease. Several different diamino acid peptides can be generated from the HRE by noncanonical translation (repeat-associated non-ATG translation, or RAN translation), and some of these peptides can be toxic. Here, we studied the effects of two arginine containing RAN translation products [proline/arginine repeated 20 times (PR20) and glycine/arginine repeated 20 times (GR20)] in primary rat spinal cord neuron cultures grown on an astrocyte feeder layer. We find that PR20 kills motor neurons with an LD50 of 2 µM, but in contrast to the effects of other ALS-causing mutant proteins (i.e., SOD or TDP43), PR20 does not evoke the biochemical signature of mitochondrial dysfunction, ER stress, or mTORC down-regulation. PR20 does result in a time-dependent build-up of ubiquitylated substrates, and this is associated with a reduction of flux through both autophagic and proteasomal degradation pathways. GR20, however, does not have these effects. The effects of PR20 on the proteasome are likely to be direct because (1) PR20 physically associates with proteasomes in biochemical assays, and (2) PR20 inhibits the degradation of a ubiquitylated test substrate when presented to purified proteasomes. Application of a proteasomal activator (IU1) blocks the toxic effects of PR20 on motor neuron survival. This work suggests that proteasomal activators have therapeutic potential in individuals with C9ORF72 HRE.
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N-Myristoylation of the Rpt2 subunit of the yeast 26S proteasome is implicated in the subcellular compartment-specific protein quality control system. J Proteomics 2015; 130:33-41. [PMID: 26344132 DOI: 10.1016/j.jprot.2015.08.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/14/2015] [Accepted: 08/27/2015] [Indexed: 12/14/2022]
Abstract
Ubiquitination is the posttranslational modification of a protein by covalent attachment of ubiquitin. Controlled proteolysis via the ubiquitin-proteasome system (\UPS) alleviates cellular stress by clearing misfolded proteins. In budding yeast, UPS within the nucleus degrades the nuclear proteins as well as proteins imported from the cytoplasm. While the predominantly nuclear localization of the yeast proteasome is maintained by the importin-mediated transport, N-myristoylation of the proteasome subunit Rpt2 was indicated to cause dynamic nucleo-cytoplasmic localization of proteasomes. Here, we quantitatively analyzed the ubiquitinated peptides using anti-K-ε-GG antibody in yeast cell lines with or without a mutation in the N-myristoylation site of Rpt2 and detected upregulated ubiquitination of proteins with nucleo-cytoplasmic localizations in the mutant strains. Moreover, both the protein and ubiquitinated peptide levels of two Hsp70 family chaperones involved in the nuclear import of misfolded proteins, Ssa and Sse1, were elevated in the mutant strains, whereas levels of an Hsp70 family chaperone involved in the nuclear export, Ssb, were reduced. Taken together, our results indicate that N-myristoylation of Rpt2 is involved in controlled proteolysis via regulation of the nucleo-cytoplasmic localization of the yeast proteasome.
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Piña FJ, Niwa M. The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance. eLife 2015; 4. [PMID: 26327697 PMCID: PMC4555637 DOI: 10.7554/elife.06970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/04/2015] [Indexed: 12/11/2022] Open
Abstract
Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle.
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Affiliation(s)
- Francisco J Piña
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
| | - Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
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18
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Bill RM, von der Haar T. Hijacked then lost in translation: the plight of the recombinant host cell in membrane protein structural biology projects. Curr Opin Struct Biol 2015; 32:147-55. [PMID: 26037971 PMCID: PMC4521084 DOI: 10.1016/j.sbi.2015.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/10/2015] [Accepted: 04/10/2015] [Indexed: 11/13/2022]
Abstract
Membrane protein structural biologists need high-quality protein for crystallisation. Recombinant proteins are central to the structural biology supply chain. Understanding quality control in protein production is an emerging trend. The roles of translation and protein folding in the host cell are examined.
Membrane protein structural biology is critically dependent upon the supply of high-quality protein. Over the last few years, the value of crystallising biochemically characterised, recombinant targets that incorporate stabilising mutations has been established. Nonetheless, obtaining sufficient yields of many recombinant membrane proteins is still a major challenge. Solutions are now emerging based on an improved understanding of recombinant host cells; as a ‘cell factory’ each cell is tasked with managing limited resources to simultaneously balance its own growth demands with those imposed by an expression plasmid. This review examines emerging insights into the role of translation and protein folding in defining high-yielding recombinant membrane protein production in a range of host cells.
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Affiliation(s)
- Roslyn M Bill
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
| | - Tobias von der Haar
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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19
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Amen T, Kaganovich D. Dynamic droplets: the role of cytoplasmic inclusions in stress, function, and disease. Cell Mol Life Sci 2015; 72:401-415. [PMID: 25283146 PMCID: PMC11113435 DOI: 10.1007/s00018-014-1740-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/16/2014] [Accepted: 09/22/2014] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases and other proteinopathies constitute a class of several dozen illnesses etiologically linked to pathological protein misfolding and aggregation. Because of this strong association with disease pathology, cell death, and aging, accumulation of proteins in aggregates or aggregation-associated structures (inclusions) has come to be regarded by many as a deleterious process, to be avoided if possible. Recent work has led us to see inclusion structures and disordered aggregate-like protein mixtures (which we call dynamic droplets) in a new light: not necessarily as a result of a pathological breakdown of cellular order, but as an elaborate cellular architecture regulating function and stress response. In this review, we discuss what is currently known about the role of inclusion structures in cellular homeostasis, stress response, toxicity, and disease. We will focus on possible mechanisms of aggregate toxicity, in contrast to the homeostatic function of several inclusion structures.
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Affiliation(s)
- Triana Amen
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Alexander Grass Center for Bioengineering, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Kaganovich
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
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Abstract
The proper folding of proteins is continuously challenged by intrinsic and extrinsic stresses, and the accumulation of toxic misfolded proteins is associated with many human diseases. Eukaryotic cells have evolved a complex network of protein quality control pathways to protect the proteome, and these pathways are specialized for each subcellular compartment. While many details have been elucidated for how the cytosol and endoplasmic reticulum counteract proteotoxic stress, relatively little is known about the pathways protecting the nucleus from protein misfolding. Proper maintenance of nuclear proteostasis has important implications in preserving genomic integrity, as well as for aging and disease. Here, we offer a conceptual framework for how proteostasis is maintained in this organelle. We define the particular requirements that must be considered for the nucleus to manage proteotoxic stress, summarize the known and implicated pathways of nuclear protein quality control, and identify the unresolved questions in the field.
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Affiliation(s)
- Yoko Shibata
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA
| | - Richard I Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA.
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21
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Latonen L. Protein aggregation in neurodegenerative disease: the nucleolar connection. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.3.324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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22
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Enenkel C. Nuclear transport of yeast proteasomes. Biomolecules 2014; 4:940-55. [PMID: 25333764 PMCID: PMC4279164 DOI: 10.3390/biom4040940] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/18/2014] [Accepted: 09/26/2014] [Indexed: 12/25/2022] Open
Abstract
Proteasomes are conserved protease complexes enriched in the nuclei of dividing yeast cells, a major site for protein degradation. If yeast cells do not proliferate and transit to quiescence, metabolic changes result in the dissociation of proteasomes into proteolytic core and regulatory complexes and their sequestration into motile cytosolic proteasome storage granuli. These granuli rapidly clear with the resumption of growth, releasing the stored proteasomes, which relocalize back to the nucleus to promote cell cycle progression. Here, I report on three models of how proteasomes are transported from the cytoplasm into the nucleus of yeast cells. The first model applies for dividing yeast and is based on the canonical pathway using classical nuclear localization sequences of proteasomal subcomplexes and the classical import receptor importin/karyopherin αβ. The second model applies for quiescent yeast cells, which resume growth and use Blm10, a HEAT-like repeat protein structurally related to karyopherin β, for nuclear import of proteasome core particles. In the third model, the fully-assembled proteasome is imported into the nucleus. Our still marginal knowledge about proteasome dynamics will inspire the discussion on how protein degradation by proteasomes may be regulated in different cellular compartments of dividing and quiescent eukaryotic cells.
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Affiliation(s)
- Cordula Enenkel
- Department of Biochemistry, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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