1
|
Ouyang Y, Jeong MY, Cunningham CN, Berg JA, Toshniwal AG, Hughes CE, Seiler K, Van Vranken JG, Cluntun AA, Lam G, Winter JM, Akdogan E, Dove KK, Nowinski SM, West M, Odorizzi G, Gygi SP, Dunn CD, Winge DR, Rutter J. Phosphate starvation signaling increases mitochondrial membrane potential through respiration-independent mechanisms. eLife 2024; 13:e84282. [PMID: 38251707 PMCID: PMC10846858 DOI: 10.7554/elife.84282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/19/2024] [Indexed: 01/23/2024] Open
Abstract
Mitochondrial membrane potential directly powers many critical functions of mitochondria, including ATP production, mitochondrial protein import, and metabolite transport. Its loss is a cardinal feature of aging and mitochondrial diseases, and cells closely monitor membrane potential as an indicator of mitochondrial health. Given its central importance, it is logical that cells would modulate mitochondrial membrane potential in response to demand and environmental cues, but there has been little exploration of this question. We report that loss of the Sit4 protein phosphatase in yeast increases mitochondrial membrane potential, both by inducing the electron transport chain and the phosphate starvation response. Indeed, a similarly elevated mitochondrial membrane potential is also elicited simply by phosphate starvation or by abrogation of the Pho85-dependent phosphate sensing pathway. This enhanced membrane potential is primarily driven by an unexpected activity of the ADP/ATP carrier. We also demonstrate that this connection between phosphate limitation and enhancement of mitochondrial membrane potential is observed in primary and immortalized mammalian cells as well as in Drosophila. These data suggest that mitochondrial membrane potential is subject to environmental stimuli and intracellular signaling regulation and raise the possibility for therapeutic enhancement of mitochondrial function even in defective mitochondria.
Collapse
Affiliation(s)
- Yeyun Ouyang
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Mi-Young Jeong
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Corey N Cunningham
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Jordan A Berg
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Ashish G Toshniwal
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Casey E Hughes
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Kristina Seiler
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | | | - Ahmad A Cluntun
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Geanette Lam
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Jacob M Winter
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Emel Akdogan
- Department of Molecular Biology and Genetics, Koç UniversityİstanbulTurkey
| | - Katja K Dove
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Sara M Nowinski
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
| | - Matthew West
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, BoulderBoulderUnited States
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, BoulderBoulderUnited States
| | - Steven P Gygi
- Department of Cell Biology, Harvard University School of MedicineBostonUnited States
| | - Cory D Dunn
- Department of Molecular Biology and Genetics, Koç UniversityİstanbulTurkey
- Institute of Biotechnology, University of HelsinkiHelsinkiFinland
| | - Dennis R Winge
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
- Department of Medicine, The University of UtahSalt Lake CityUnited States
| | - Jared Rutter
- Department of Biochemistry, The University of UtahSalt Lake CityUnited States
- Howard Hughes Medical Institute, University of UtahSalt Lake CityUnited States
| |
Collapse
|
2
|
Winter JM, Fresenius HL, Cunningham CN, Wei P, Keys HR, Berg J, Bott A, Yadav T, Ryan J, Sirohi D, Tripp SR, Barta P, Agarwal N, Letai A, Sabatini DM, Wohlever ML, Rutter J. Collateral deletion of the mitochondrial AAA+ ATPase ATAD1 sensitizes cancer cells to proteasome dysfunction. eLife 2022; 11:82860. [PMID: 36409067 DOI: 10.7554/elife.82860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 11/20/2022] [Indexed: 11/23/2022] Open
Abstract
The tumor suppressor gene PTEN is the second most commonly deleted gene in cancer. Such deletions often include portions of the chromosome 10q23 locus beyond the bounds of PTEN itself, which frequently disrupts adjacent genes. Coincidental loss of PTEN-adjacent genes might impose vulnerabilities that could either affect patient outcome basally or be exploited therapeutically. Here, we describe how the loss of ATAD1, which is adjacent to and frequently co-deleted with PTEN, predisposes cancer cells to apoptosis triggered by proteasome dysfunction and correlates with improved survival in cancer patients. ATAD1 directly and specifically extracts the pro-apoptotic protein BIM from mitochondria to inactivate it. Cultured cells and mouse xenografts lacking ATAD1 are hypersensitive to clinically used proteasome inhibitors, which activate BIM and trigger apoptosis. This work furthers our understanding of mitochondrial protein homeostasis and could lead to new therapeutic options for the hundreds of thousands of cancer patients who have tumors with chromosome 10q23 deletion.
Collapse
Affiliation(s)
- Jacob M Winter
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Heidi L Fresenius
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, United States
| | - Corey N Cunningham
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Peng Wei
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Jordan Berg
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Alex Bott
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Tarun Yadav
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Jeremy Ryan
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - Deepika Sirohi
- University of Utah and ARUP Laboratories, Salt Lake City, United States
| | - Sheryl R Tripp
- University of Utah and ARUP Laboratories, Salt Lake City, United States
| | - Paige Barta
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Neeraj Agarwal
- Huntsman Cancer Institute, University of Utah, Salt Lake City, United States
| | - Anthony Letai
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - David M Sabatini
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Matthew L Wohlever
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, United States
| | - Jared Rutter
- Department of Biochemistry, University of Utah, Salt Lake City, United States.,Huntsman Cancer Institute, University of Utah, Salt Lake City, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
| |
Collapse
|
3
|
Wei P, Bott AJ, Cluntun AA, Morgan JT, Cunningham CN, Schell JC, Ouyang Y, Ficarro SB, Marto JA, Danial NN, DeBerardinis RJ, Rutter J. Mitochondrial pyruvate supports lymphoma proliferation by fueling a glutamate pyruvate transaminase 2-dependent glutaminolysis pathway. Sci Adv 2022; 8:eabq0117. [PMID: 36179030 PMCID: PMC9524954 DOI: 10.1126/sciadv.abq0117] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/04/2022] [Indexed: 06/14/2023]
Abstract
The fate of pyruvate is a defining feature in many cell types. One major fate is mitochondrial entry via the mitochondrial pyruvate carrier (MPC). We found that diffuse large B cell lymphomas (DLBCLs) consume mitochondrial pyruvate via glutamate-pyruvate transaminase 2 to enable α-ketoglutarate production as part of glutaminolysis. This led us to discover that glutamine exceeds pyruvate as a carbon source for the tricarboxylic acid cycle in DLBCLs. As a result, MPC inhibition led to decreased glutaminolysis in DLBCLs, opposite to previous observations in other cell types. We also found that MPC inhibition or genetic depletion decreased DLBCL proliferation in an extracellular matrix (ECM)-like environment and xenografts, but not in a suspension environment. Moreover, the metabolic profile of DLBCL cells in ECM is markedly different from cells in a suspension environment. Thus, we conclude that the synergistic consumption and assimilation of glutamine and pyruvate enables DLBCL proliferation in an extracellular environment-dependent manner.
Collapse
Affiliation(s)
- Peng Wei
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Alex J. Bott
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ahmad A. Cluntun
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Jeffrey T. Morgan
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Corey N. Cunningham
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - John C. Schell
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Yeyun Ouyang
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Scott B. Ficarro
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
- Blais Proteomics Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Jarrod A. Marto
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
- Blais Proteomics Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Nika N. Danial
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Ralph J. DeBerardinis
- Children’s Medical Center Research Institute, University of Texas (UT) Southwestern Medical Center, Dallas, TX 75390, USA
- Howard Hughes Medical Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| |
Collapse
|
4
|
Cluntun AA, Badolia R, Lettlova S, Parnell KM, Shankar TS, Diakos NA, Olson KA, Taleb I, Tatum SM, Berg JA, Cunningham CN, Van Ry T, Bott AJ, Krokidi AT, Fogarty S, Skedros S, Swiatek WI, Yu X, Luo B, Merx S, Navankasattusas S, Cox JE, Ducker GS, Holland WL, McKellar SH, Rutter J, Drakos SG. The pyruvate-lactate axis modulates cardiac hypertrophy and heart failure. Cell Metab 2021; 33:629-648.e10. [PMID: 33333007 PMCID: PMC7933116 DOI: 10.1016/j.cmet.2020.12.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 10/12/2020] [Accepted: 12/02/2020] [Indexed: 12/21/2022]
Abstract
The metabolic rewiring of cardiomyocytes is a widely accepted hallmark of heart failure (HF). These metabolic changes include a decrease in mitochondrial pyruvate oxidation and an increased export of lactate. We identify the mitochondrial pyruvate carrier (MPC) and the cellular lactate exporter monocarboxylate transporter 4 (MCT4) as pivotal nodes in this metabolic axis. We observed that cardiac assist device-induced myocardial recovery in chronic HF patients was coincident with increased myocardial expression of the MPC. Moreover, the genetic ablation of the MPC in cultured cardiomyocytes and in adult murine hearts was sufficient to induce hypertrophy and HF. Conversely, MPC overexpression attenuated drug-induced hypertrophy in a cell-autonomous manner. We also introduced a novel, highly potent MCT4 inhibitor that mitigated hypertrophy in cultured cardiomyocytes and in mice. Together, we find that alteration of the pyruvate-lactate axis is a fundamental and early feature of cardiac hypertrophy and failure.
Collapse
Affiliation(s)
- Ahmad A Cluntun
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Rachit Badolia
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Sandra Lettlova
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - K Mark Parnell
- Vettore Biosciences, 1700 Owens Street Suite 515, San Francisco, CA 94158, USA
| | - Thirupura S Shankar
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Nikolaos A Diakos
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Kristofor A Olson
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Iosif Taleb
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Sean M Tatum
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, UT 84112, USA
| | - Jordan A Berg
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Corey N Cunningham
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Tyler Van Ry
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA; Metabolomics, Proteomics and Mass Spectrometry Core Facility, University of Utah, Salt Lake City, UT 84112, USA
| | - Alex J Bott
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Aspasia Thodou Krokidi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Sarah Fogarty
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Sophia Skedros
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Wojciech I Swiatek
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - Xuejing Yu
- University of Utah, School of Medicine, Salt Lake City, UT 84132, USA; Division of Cardiothoracic Surgery, Department of Surgery, Salt Lake City, UT 84132, USA
| | - Bai Luo
- Drug Discovery Core Facility, University of Utah, Salt Lake City, UT 84112, USA
| | - Shannon Merx
- Vettore Biosciences, 1700 Owens Street Suite 515, San Francisco, CA 94158, USA
| | - Sutip Navankasattusas
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - James E Cox
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA; Metabolomics, Proteomics and Mass Spectrometry Core Facility, University of Utah, Salt Lake City, UT 84112, USA
| | - Gregory S Ducker
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA
| | - William L Holland
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, UT 84112, USA
| | - Stephen H McKellar
- University of Utah, School of Medicine, Salt Lake City, UT 84132, USA; Division of Cardiothoracic Surgery, Department of Surgery, Salt Lake City, UT 84132, USA; U.T.A.H. (Utah Transplant Affiliated Hospitals) Cardiac Transplant Program: University of Utah Healthcare and School of Medicine, Intermountain Medical Center, Salt Lake VA (Veterans Affairs) Health Care System, Salt Lake City, UT, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84132, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - Stavros G Drakos
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA; U.T.A.H. (Utah Transplant Affiliated Hospitals) Cardiac Transplant Program: University of Utah Healthcare and School of Medicine, Intermountain Medical Center, Salt Lake VA (Veterans Affairs) Health Care System, Salt Lake City, UT, USA.
| |
Collapse
|
5
|
Cunningham CN, Rutter J. 20,000 picometers under the OMM: diving into the vastness of mitochondrial metabolite transport. EMBO Rep 2020; 21:e50071. [PMID: 32329174 DOI: 10.15252/embr.202050071] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/17/2020] [Accepted: 03/27/2020] [Indexed: 12/14/2022] Open
Abstract
The metabolic compartmentalization enabled by mitochondria is key feature of many cellular processes such as energy conversion to ATP production, redox balance, and the biosynthesis of heme, urea, nucleotides, lipids, and others. For a majority of these functions, metabolites need to be transported across the impermeable inner mitochondrial membrane by dedicated carrier proteins. Here, we examine the substrates, structural features, and human health implications of four mitochondrial metabolite carrier families: the SLC25A family, the mitochondrial ABCB transporters, the mitochondrial pyruvate carrier (MPC), and the sideroflexin proteins.
Collapse
Affiliation(s)
- Corey N Cunningham
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.,Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT, USA
| |
Collapse
|
6
|
Cunningham CN, Williams JM, Knupp J, Arunagiri A, Arvan P, Tsai B. Cells Deploy a Two-Pronged Strategy to Rectify Misfolded Proinsulin Aggregates. Mol Cell 2019; 75:442-456.e4. [PMID: 31176671 DOI: 10.1016/j.molcel.2019.05.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/17/2019] [Accepted: 05/08/2019] [Indexed: 02/06/2023]
Abstract
Insulin gene coding sequence mutations are known to cause mutant INS-gene-induced diabetes of youth (MIDY), yet the cellular pathways needed to prevent misfolded proinsulin accumulation remain incompletely understood. Here, we report that Akita mutant proinsulin forms detergent-insoluble aggregates that entrap wild-type (WT) proinsulin in the endoplasmic reticulum (ER), thereby blocking insulin production. Two distinct quality-control mechanisms operate together to combat this insult: the ER luminal chaperone Grp170 prevents proinsulin aggregation, while the ER membrane morphogenic protein reticulon-3 (RTN3) disposes of aggregates via ER-coupled autophagy (ER-phagy). We show that enhanced RTN-dependent clearance of aggregated Akita proinsulin helps to restore ER export of WT proinsulin, which can promote WT insulin production, potentially alleviating MIDY. We also find that RTN3 participates in the clearance of other mutant prohormone aggregates. Together, these results identify a series of substrates of RTN3-mediated ER-phagy, highlighting RTN3 in the disposal of pathogenic prohormone aggregates.
Collapse
Affiliation(s)
- Corey N Cunningham
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jeffrey M Williams
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA
| | - Jeffrey Knupp
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anoop Arunagiri
- Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter Arvan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Billy Tsai
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| |
Collapse
|
7
|
Arunagiri A, Haataja L, Cunningham CN, Shrestha N, Tsai B, Qi L, Liu M, Arvan P. Misfolded proinsulin in the endoplasmic reticulum during development of beta cell failure in diabetes. Ann N Y Acad Sci 2018; 1418:5-19. [PMID: 29377149 DOI: 10.1111/nyas.13531] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is broadly distributed throughout the cytoplasm of pancreatic beta cells, and this is where all proinsulin is initially made. Healthy beta cells can synthesize 6000 proinsulin molecules per second. Ordinarily, nascent proinsulin entering the ER rapidly folds via the formation of three evolutionarily conserved disulfide bonds (B7-A7, B19-A20, and A6-A11). A modest amount of proinsulin misfolding, including both intramolecular disulfide mispairing and intermolecular disulfide-linked protein complexes, is a natural by-product of proinsulin biosynthesis, as is the case for many proteins. The steady-state level of misfolded proinsulin-a potential ER stressor-is linked to (1) production rate, (2) ER environment, (3) presence or absence of naturally occurring (mutational) defects in proinsulin, and (4) clearance of misfolded proinsulin molecules. Accumulation of misfolded proinsulin beyond a certain threshold begins to interfere with the normal intracellular transport of bystander proinsulin, leading to diminished insulin production and hyperglycemia, as well as exacerbating ER stress. This is most obvious in mutant INS gene-induced Diabetes of Youth (MIDY; an autosomal dominant disease) but also likely to occur in type 2 diabetes owing to dysregulation in proinsulin synthesis, ER folding environment, or clearance.
Collapse
Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Corey N Cunningham
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
8
|
Cunningham CN, He K, Arunagiri A, Paton AW, Paton JC, Arvan P, Tsai B. Chaperone-Driven Degradation of a Misfolded Proinsulin Mutant in Parallel With Restoration of Wild-Type Insulin Secretion. Diabetes 2017; 66:741-753. [PMID: 28028074 PMCID: PMC5319713 DOI: 10.2337/db16-1338] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/20/2016] [Indexed: 02/06/2023]
Abstract
In heterozygous patients with a diabetic syndrome called mutant INS gene-induced diabetes of youth (MIDY), there is decreased insulin secretion when mutant proinsulin expression prevents wild-type (WT) proinsulin from exiting the endoplasmic reticulum (ER), which is essential for insulin production. Our previous results revealed that mutant Akita proinsulin is triaged by ER-associated degradation (ERAD). We now find that the ER chaperone Grp170 participates in the degradation process by shifting Akita proinsulin from high-molecular weight (MW) complexes toward smaller oligomeric species that are competent to undergo ERAD. Strikingly, overexpressing Grp170 also liberates WT proinsulin, which is no longer trapped in these high-MW complexes, enhancing ERAD of Akita proinsulin and restoring WT insulin secretion. Our data reveal that Grp170 participates in preparing mutant proinsulin for degradation while enabling WT proinsulin escape from the ER. In principle, selective destruction of mutant proinsulin offers a rational approach to rectify the insulin secretion problem in MIDY.
Collapse
Affiliation(s)
- Corey N Cunningham
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
| | - Kaiyu He
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
| | - Anoop Arunagiri
- Division of Metabolism Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, Australia
| | - Peter Arvan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
- Division of Metabolism Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Billy Tsai
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI
| |
Collapse
|
9
|
Cunningham CN, Schmidt CA, Schramm NJ, Gaylord MR, Resendes KK. Human TREX2 components PCID2 and centrin 2, but not ENY2, have distinct functions in protein export and co-localize to the centrosome. Exp Cell Res 2013; 320:209-18. [PMID: 24291146 DOI: 10.1016/j.yexcr.2013.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 11/15/2013] [Accepted: 11/19/2013] [Indexed: 11/15/2022]
Abstract
TREX-2 is a five protein complex, conserved from yeast to humans, involved in linking mRNA transcription and export. The centrin 2 subunit of TREX-2 is also a component of the centrosome and is additionally involved in a distinctly different process of nuclear protein export. While centrin 2 is a known multifunctional protein, the roles of other human TREX-2 complex proteins other than mRNA export are not known. In this study, we found that human TREX-2 member PCID2 but not ENY2 is involved in some of the same cellular processes as those of centrin 2 apart from the classical TREX-2 function. PCID2 is present at the centrosome in a subset of HeLa cells and this localization is centrin 2 dependent. Furthermore, the presence of PCID2 at the centrosome is prevalent throughout the cell cycle as determined by co-staining with cyclins E, A and B. PCID2 but not ENY2 is also involved in protein export. Surprisingly, siRNA knockdown of PCID2 delayed the rate of nuclear protein export, a mechanism distinct from the effects of centrin 2, which when knocked down inhibits export. Finally we showed that co-depletion of centrin 2 and PCID2 leads to blocking rather than delaying nuclear protein export, indicating the dominance of the centrin 2 phenotype. Together these results represent the first discovery of specific novel functions for PCID2 other than mRNA export and suggest that components of the TREX-2 complex serve alternative shared roles in the regulation of nuclear transport and cell cycle progression.
Collapse
Affiliation(s)
- Corey N Cunningham
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Casey A Schmidt
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Nathaniel J Schramm
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA
| | - Michelle R Gaylord
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California - San Diego, 9500 Gilman Drive, #0347, La Jolla, CA 92093-0347, USA
| | - Karen K Resendes
- Westminster College, Department of Biology, 319 South Market Street, New Wilmington, PA 16172, USA.
| |
Collapse
|
10
|
Costello PS, Turner M, Walters AE, Cunningham CN, Bauer PH, Downward J, Tybulewicz VL. Critical role for the tyrosine kinase Syk in signalling through the high affinity IgE receptor of mast cells. Oncogene 1996; 13:2595-605. [PMID: 9000133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Activation of the high affinity IgE receptor (Fc epsilon RI) of mast cells, a member of the antigen receptor family, leads to the release of allergic mediators, a critical event in the onset of immediate hypersensitivity. Stimulation of Fc epsilon RI results in the rapid association and activation of the Syk tyrosine kinase. Using Syk-deficient mast cells we show that they fail to degranulate, synthesize leukotrienes and secrete cytokines when stimulated through Fc epsilon RI, conclusively demonstrating an essential role for Syk in Fc epsilon RI signalling. Furthermore, our data strongly supports a model of Fc epsilon RI engagement leading to the sequential activation of the tyrosine kinases Lyn and then Syk. A similar mechanism is likely to apply to signal transduction through all members of the antigen receptor family.
Collapse
Affiliation(s)
- P S Costello
- National Institute for Medical Research, London, UK
| | | | | | | | | | | | | |
Collapse
|