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Wang L, Xie Z, Wu M, Chen Y, Wang X, Li X, Liu F. The role of taurine through endoplasmic reticulum in physiology and pathology. Biochem Pharmacol 2024; 226:116386. [PMID: 38909788 DOI: 10.1016/j.bcp.2024.116386] [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: 03/09/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 06/25/2024]
Abstract
Taurine is a sulfur-containing amino acid found in many cell organelles that plays a wide range of biological roles, including bile salt production, osmoregulation, oxidative stress reduction, and neuromodulation. Taurine treatments have also been shown to ameliorate the onset and development of many diseases, including hypertension, fatty liver, neurodegenerative diseases and ischemia-reperfusion injury, by exerting antioxidant, anti-inflammatory, and antiapoptotic effects. The endoplasmic reticulum (ER) is a dynamic organelle involved in a wide range of cellular functions, including lipid metabolism, calcium storage and protein stabilization. Under stress, the disruption of the ER environment leads to the accumulation of misfolded proteins and a characteristic stress response called the unfolded protein response (UPR). The UPR protects cells from stress and helps to restore cellular homeostasis, but its activation promotes cell death under prolonged ER stress. Recent studies have shown that ER stress is closely related to the onset and development of many diseases. This article reviews the beneficial effects and related mechanisms of taurine by regulating the ER in different physiological and pathological states, with the aim of providing a reference for further research and clinical applications.
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Affiliation(s)
- Linfeng Wang
- Institute of Microbial Engineering, School of Life Sciences, Henan University, Kaifeng 475004, China; Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, 475004, China
| | - Zhenxing Xie
- School of Basic Medical Sciences, Henan University, Kaifeng 475004, China
| | - Mengxian Wu
- Institute of Microbial Engineering, School of Life Sciences, Henan University, Kaifeng 475004, China; Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, 475004, China
| | - Yunayuan Chen
- Institute of Microbial Engineering, School of Life Sciences, Henan University, Kaifeng 475004, China; Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, 475004, China
| | - Xin Wang
- Institute of Microbial Engineering, School of Life Sciences, Henan University, Kaifeng 475004, China; Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, 475004, China
| | - Xingke Li
- Institute of Microbial Engineering, School of Life Sciences, Henan University, Kaifeng 475004, China; Engineering Research Center for Applied Microbiology of Henan Province, Kaifeng, 475004, China.
| | - Fangli Liu
- College of Nursing and Health, Henan University, Kaifeng 475004, China.
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2
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Cremer T, Hoelen H, van de Weijer ML, Janssen GM, Costa AI, van Veelen PA, Lebbink RJ, Wiertz EJHJ. Proinsulin degradation and presentation of a proinsulin B-chain autoantigen involves ER-associated protein degradation (ERAD)-enzyme UBE2G2. PLoS One 2024; 19:e0287877. [PMID: 38787820 PMCID: PMC11125532 DOI: 10.1371/journal.pone.0287877] [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: 06/14/2023] [Accepted: 03/14/2024] [Indexed: 05/26/2024] Open
Abstract
Type 1 diabetes (T1D) is characterized by HLA class I-mediated presentation of autoantigens on the surface of pancreatic β-cells. Recognition of these autoantigens by CD8+ T cells results in the destruction of pancreatic β-cells and, consequently, insulin deficiency. Most epitopes presented at the surface of β-cells derive from the insulin precursor molecule proinsulin. The intracellular processing pathway(s) involved in the generation of these peptides are poorly defined. In this study, we show that a proinsulin B-chain antigen (PPIB5-14) originates from proinsulin molecules that are processed by ER-associated protein degradation (ERAD) and thus originate from ER-resident proteins. Furthermore, screening genes encoding for E2 ubiquitin conjugating enzymes, we identified UBE2G2 to be involved in proinsulin degradation and subsequent presentation of the PPIB10-18 autoantigen. These insights into the pathway involved in the generation of insulin-derived peptides emphasize the importance of proinsulin processing in the ER to T1D pathogenesis and identify novel targets for future T1D therapies.
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Affiliation(s)
- Tom Cremer
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
| | - Hanneke Hoelen
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - George M. Janssen
- Department of Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ana I. Costa
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter A. van Veelen
- Department of Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Moghadam RK, Daraei A, Haddadi M, Mardi A, Karamali N, Rezaiemanesh A. Casting Light on the Janus-Faced HMG-CoA Reductase Degradation Protein 1: A Comprehensive Review of Its Dualistic Impact on Apoptosis in Various Diseases. Mol Neurobiol 2024:10.1007/s12035-024-03994-z. [PMID: 38356096 DOI: 10.1007/s12035-024-03994-z] [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: 12/05/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
Nowadays, it is well recognized that apoptosis, as a highly regulated cellular process, plays a crucial role in various biological processes, such as cell differentiation. Dysregulation of apoptosis is strongly implicated in the pathophysiology of numerous disorders, making it essential to comprehend its underlying mechanisms. One key factor that has garnered significant attention in the regulation of apoptotic pathways is HMG-CoA reductase degradation protein 1, also known as HRD1. HRD1 is an E3 ubiquitin ligase located in the endoplasmic reticulum (ER) membrane. Its primary role involves maintaining the quality control of ER proteins by facilitating the ER-associated degradation (ERAD) pathway. During ER stress, HRD1 aids in the elimination of misfolded proteins that accumulate within the ER. Therefore, HRD1 plays a pivotal role in the regulation of apoptotic pathways and maintenance of ER protein quality control. By targeting specific protein substrates and affecting apoptosis-related pathways, HRD1 could be an exclusive therapeutic target in different disorders. Dysregulation of HRD1-mediated processes contributes significantly to the pathophysiology of various diseases. The purpose of this review is to assess the effect of HRD1 on the pathways related to apoptosis in various diseases from a therapeutic perspective.
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Affiliation(s)
- Reihaneh Khaleghi Moghadam
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Arshia Daraei
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Maryam Haddadi
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Amirhossein Mardi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Negin Karamali
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Alireza Rezaiemanesh
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran.
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4
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Chen Z, Wang S, Pottekat A, Duffey A, Jang I, Chang BH, Cho J, Finck BN, Davidson NO, Kaufman RJ. Conditional hepatocyte ablation of PDIA1 uncovers indispensable roles in both APOB and MTTP folding to support VLDL secretion. Mol Metab 2024; 80:101874. [PMID: 38211723 PMCID: PMC10832468 DOI: 10.1016/j.molmet.2024.101874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/04/2024] [Accepted: 01/06/2024] [Indexed: 01/13/2024] Open
Abstract
OBJECTIVES The assembly and secretion of hepatic very low-density lipoprotein (VLDL) plays pivotal roles in hepatic and plasma lipid homeostasis. Protein disulfide isomerase A1 (PDIA1/P4HB) is a molecular chaperone whose functions are essential for protein folding in the endoplasmic reticulum. Here we investigated the physiological requirement in vivo for PDIA1 in maintaining VLDL assembly and secretion. METHODS Pdia1/P4hb was conditionally deleted in adult mouse hepatocytes and the phenotypes characterized. Mechanistic analyses in primary hepatocytes determined how PDIA1 ablation alters MTTP synthesis and degradation as well as altering synthesis and secretion of Apolipoprotein B (APOB), along with complementary expression of intact PDIA1 vs a catalytically inactivated PDIA1 mutant. RESULTS Hepatocyte-specific deletion of Pdia1/P4hb inhibited hepatic MTTP expression and dramatically reduced VLDL production, leading to severe hepatic steatosis and hypolipidemia. Pdia1-deletion did not affect mRNA expression or protein stability of MTTP but rather prevented Mttp mRNA translation. We demonstrate an essential role for PDIA1 in MTTP synthesis and function and show that PDIA1 interacts with APOB in an MTTP-independent manner via its molecular chaperone function to support APOB folding and secretion. CONCLUSIONS PDIA1 plays indispensable roles in APOB folding, MTTP synthesis and activity to support VLDL assembly. Thus, like APOB and MTTP, PDIA1 is an obligatory component of hepatic VLDL production.
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Affiliation(s)
- Zhouji Chen
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA.
| | - Shiyu Wang
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Anita Pottekat
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Alec Duffey
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Insook Jang
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA
| | - Benny H Chang
- Section of Nephrology, Division of Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jaehyung Cho
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Brian N Finck
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicholas O Davidson
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Genetics and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, 10901 N. Torrey Pines Rd, La Jolla CA 92037, USA.
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Robinson CM, Duggan A, Forrester A. ER exit in physiology and disease. Front Mol Biosci 2024; 11:1352970. [PMID: 38314136 PMCID: PMC10835805 DOI: 10.3389/fmolb.2024.1352970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/05/2024] [Indexed: 02/06/2024] Open
Abstract
The biosynthetic secretory pathway is comprised of multiple steps, modifications and interactions that form a highly precise pathway of protein trafficking and secretion, that is essential for eukaryotic life. The general outline of this pathway is understood, however the specific mechanisms are still unclear. In the last 15 years there have been vast advancements in technology that enable us to advance our understanding of this complex and subtle pathway. Therefore, based on the strong foundation of work performed over the last 40 years, we can now build another level of understanding, using the new technologies available. The biosynthetic secretory pathway is a high precision process, that involves a number of tightly regulated steps: Protein folding and quality control, cargo selection for Endoplasmic Reticulum (ER) exit, Golgi trafficking, sorting and secretion. When deregulated it causes severe diseases that here we categorise into three main groups of aberrant secretion: decreased, excess and altered secretion. Each of these categories disrupts organ homeostasis differently, effecting extracellular matrix composition, changing signalling events, or damaging the secretory cells due to aberrant intracellular accumulation of secretory proteins. Diseases of aberrant secretion are very common, but despite this, there are few effective therapies. Here we describe ER exit sites (ERES) as key hubs for regulation of the secretory pathway, protein quality control and an integratory hub for signalling within the cell. This review also describes the challenges that will be faced in developing effective therapies, due to the specificity required of potential drug candidates and the crucial need to respect the fine equilibrium of the pathway. The development of novel tools is moving forward, and we can also use these tools to build our understanding of the acute regulation of ERES and protein trafficking. Here we review ERES regulation in context as a therapeutic strategy.
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Affiliation(s)
- Claire M Robinson
- School of Medicine, Health Sciences Centre, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Aislinn Duggan
- School of Medicine, Health Sciences Centre, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Alison Forrester
- Research Unit of Cell Biology (URBC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium
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Chen G, Wei T, Ju F, Li H. Protein quality control and aggregation in the endoplasmic reticulum: From basic to bedside. Front Cell Dev Biol 2023; 11:1156152. [PMID: 37152279 PMCID: PMC10154544 DOI: 10.3389/fcell.2023.1156152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
Endoplasmic reticulum (ER) is the largest membrane-bound compartment in all cells and functions as a key regulator in protein biosynthesis, lipid metabolism, and calcium balance. Mammalian endoplasmic reticulum has evolved with an orchestrated protein quality control system to handle defective proteins and ensure endoplasmic reticulum homeostasis. Nevertheless, the accumulation and aggregation of misfolded proteins in the endoplasmic reticulum may occur during pathological conditions. The inability of endoplasmic reticulum quality control system to clear faulty proteins and aggregates from the endoplasmic reticulum results in the development of many human disorders. The efforts to comprehensively understand endoplasmic reticulum quality control network and protein aggregation will benefit the diagnostics and therapeutics of endoplasmic reticulum storage diseases. Herein, we overview recent advances in mammalian endoplasmic reticulum protein quality control system, describe protein phase transition model, and summarize the approaches to monitor protein aggregation. Moreover, we discuss the therapeutic applications of enhancing endoplasmic reticulum protein quality control pathways in endoplasmic reticulum storage diseases.
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Affiliation(s)
- Guofang Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Tingyi Wei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Furong Ju
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Sha Tin, Hong kong SAR, China
| | - Haisen Li
- School of Life Sciences, Fudan University, Shanghai, China
- AoBio Medical, Shanghai, China
- *Correspondence: Haisen Li,
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7
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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: 0] [Impact Index Per Article: 0] [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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8
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Karamali N, Ebrahimnezhad S, Khaleghi Moghadam R, Daneshfar N, Rezaiemanesh A. HRD1 in human malignant neoplasms: Molecular mechanisms and novel therapeutic strategy for cancer. Life Sci 2022; 301:120620. [PMID: 35533759 DOI: 10.1016/j.lfs.2022.120620] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/01/2022] [Accepted: 05/04/2022] [Indexed: 10/18/2022]
Abstract
In tumor cells, the endoplasmic reticulum (ER) plays an essential role in maintaining cellular proteostasis by stimulating unfolded protein response (UPR) underlying stress conditions. ER-associated degradation (ERAD) is a critical pathway of the UPR to protect cells from ER stress-induced apoptosis and the elimination of unfolded or misfolded proteins by the ubiquitin-proteasome system (UPS). 3-Hydroxy-3-methylglutaryl reductase degradation (HRD1) as an E3 ubiquitin ligase plays an essential role in the ubiquitination and dislocation of misfolded protein in ERAD. In addition, HRD1 can target other normal folded proteins. In various types of cancer, the expression of HRD1 is dysregulated, and it targets different molecules to develop cancer hallmarks or suppress the progression of the disease. Recent investigations have defined the role of HRD1 in drug resistance in types of cancer. This review focuses on the molecular mechanisms of HRD1 and its roles in cancer pathogenesis and discusses the worthiness of targeting HRD1 as a novel therapeutic strategy in cancer.
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Affiliation(s)
- Negin Karamali
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Samaneh Ebrahimnezhad
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Reihaneh Khaleghi Moghadam
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Niloofar Daneshfar
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran; Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
| | - Alireza Rezaiemanesh
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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Reggiori F, Molinari M. ER-phagy: mechanisms, regulation and diseases connected to the lysosomal clearance of the endoplasmic reticulum. Physiol Rev 2022; 102:1393-1448. [PMID: 35188422 PMCID: PMC9126229 DOI: 10.1152/physrev.00038.2021] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
ER-phagy (reticulo-phagy) defines the degradation of portions of the endoplasmic reticulum (ER) within lysosomes or vacuoles. It is part of the self-digestion (i.e., auto-phagic) programs recycling cytoplasmic material and organelles, which rapidly mobilize metabolites in cells confronted with nutrient shortage. Moreover, selective clearance of ER subdomains participates to the control of ER size and activity during ER stress, the re-establishment of ER homeostasis after ER stress resolution and the removal of ER parts, in which aberrant and potentially cytotoxic material has been segregated. ER-phagy relies on the individual and/or concerted activation of the ER-phagy receptors, ER peripheral or integral membrane proteins that share the presence of LC3/Atg8-binding motifs in their cytosolic domains. ER-phagy involves the physical separation of portions of the ER from the bulk ER network, and their delivery to the endolysosomal/vacuolar catabolic district. This last step is accomplished by a variety of mechanisms including macro-ER-phagy (in which ER fragments are sequestered by double-membrane autophagosomes that eventually fuse with lysosomes/vacuoles), micro-ER-phagy (in which ER fragments are directly engulfed by endosomes/lysosomes/vacuoles), or direct fusion of ER-derived vesicles with lysosomes/vacuoles. ER-phagy is dysfunctional in specific human diseases and its regulators are subverted by pathogens, highlighting its crucial role for cell and organism life.
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Affiliation(s)
- Fulvio Reggiori
- Department of Biomedical Sciences of Cells & Systems, grid.4830.fUniversity of Groningen, Netherlands
| | - Maurizio Molinari
- Protein Folding and Quality Control, grid.7722.0Institute for Research in Biomedicine, Bellinzona, Switzerland
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10
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Li H, Sun S. Protein Aggregation in the ER: Calm behind the Storm. Cells 2021; 10:cells10123337. [PMID: 34943844 PMCID: PMC8699410 DOI: 10.3390/cells10123337] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 02/06/2023] Open
Abstract
As one of the largest organelles in eukaryotic cells, the endoplasmic reticulum (ER) plays a vital role in the synthesis, folding, and assembly of secretory and membrane proteins. To maintain its homeostasis, the ER is equipped with an elaborate network of protein folding chaperones and multiple quality control pathways whose cooperative actions safeguard the fidelity of protein biogenesis. However, due to genetic abnormalities, the error-prone nature of protein folding and assembly, and/or defects or limited capacities of the protein quality control systems, nascent proteins may become misfolded and fail to exit the ER. If not cleared efficiently, the progressive accumulation of misfolded proteins within the ER may result in the formation of toxic protein aggregates, leading to the so-called “ER storage diseases”. In this review, we first summarize our current understanding of the protein folding and quality control networks in the ER, including chaperones, unfolded protein response (UPR), ER-associated protein degradation (ERAD), and ER-selective autophagy (ER-phagy). We then survey recent research progress on a few ER storage diseases, with a focus on the role of ER quality control in the disease etiology, followed by a discussion on outstanding questions and emerging concepts in the field.
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Affiliation(s)
- Haisen Li
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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11
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Molinari M. ER-phagy responses in yeast, plants, and mammalian cells and their crosstalk with UPR and ERAD. Dev Cell 2021; 56:949-966. [PMID: 33765438 DOI: 10.1016/j.devcel.2021.03.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/23/2021] [Accepted: 02/27/2021] [Indexed: 12/24/2022]
Abstract
ER-phagy, literally endoplasmic reticulum (ER)-eating, defines the constitutive or regulated clearance of ER portions within metazoan endolysosomes or yeast and plant vacuoles. The advent of electron microscopy led to the first observations of ER-phagy over 60 years ago, but only recently, with the discovery of a set of regulatory proteins named ER-phagy receptors, has it been dissected mechanistically. ER-phagy receptors are activated by a variety of pleiotropic and ER-centric stimuli. They promote ER fragmentation and engage luminal, membrane-bound, and cytosolic factors, eventually driving lysosomal clearance of select ER domains along with their content. After short historical notes, this review introduces the concept of ER-phagy responses (ERPRs). ERPRs ensure lysosomal clearance of ER portions expendable during nutrient shortage, nonfunctional, present in excess, or containing misfolded proteins. They cooperate with unfolded protein responses (UPRs) and with ER-associated degradation (ERAD) in determining ER size, function, and homeostasis.
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Affiliation(s)
- Maurizio Molinari
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Institute for Research in Biomedicine, CH-6500 Bellinzona, Switzerland; School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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12
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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: 33] [Impact Index Per Article: 11.0] [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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13
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Ninagawa S, George G, Mori K. Mechanisms of productive folding and endoplasmic reticulum-associated degradation of glycoproteins and non-glycoproteins. Biochim Biophys Acta Gen Subj 2020; 1865:129812. [PMID: 33316349 DOI: 10.1016/j.bbagen.2020.129812] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The quality of proteins destined for the secretory pathway is ensured by two distinct mechanisms in the endoplasmic reticulum (ER): productive folding of newly synthesized proteins, which is assisted by ER-localized molecular chaperones and in most cases also by disulfide bond formation and transfer of an oligosaccharide unit; and ER-associated degradation (ERAD), in which proteins unfolded or misfolded in the ER are recognized and processed for delivery to the ER membrane complex, retrotranslocated through the complex with simultaneous ubiquitination, extracted by AAA-ATPase to the cytosol, and finally degraded by the proteasome. SCOPE OF REVIEW We describe the mechanisms of productive folding and ERAD, with particular attention to glycoproteins versus non-glycoproteins, and to yeast versus mammalian systems. MAJOR CONCLUSION Molecular mechanisms of the productive folding of glycoproteins and non-glycoproteins mediated by molecular chaperones and protein disulfide isomerases are well conserved from yeast to mammals. Additionally, mammals have gained an oligosaccharide structure-dependent folding cycle for glycoproteins. The molecular mechanisms of ERAD are also well conserved from yeast to mammals, but redundant expression of yeast orthologues in mammals has been encountered, particularly for components involved in recognition and processing of glycoproteins and components of the ER membrane complex involved in retrotranslocation and simultaneous ubiquitination of glycoproteins and non-glycoproteins. This may reflect an evolutionary consequence of increasing quantity or quality needs toward mammals. GENERAL SIGNIFICANCE The introduction of innovative genome editing technology into analysis of the mechanisms of mammalian ERAD, as exemplified here, will provide new insights into the pathogenesis of various diseases.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Ginto George
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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14
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Ninagawa S, Tada S, Okumura M, Inoguchi K, Kinoshita M, Kanemura S, Imami K, Umezawa H, Ishikawa T, Mackin RB, Torii S, Ishihama Y, Inaba K, Anazawa T, Nagamine T, Mori K. Antipsychotic olanzapine-induced misfolding of proinsulin in the endoplasmic reticulum accounts for atypical development of diabetes. eLife 2020; 9:60970. [PMID: 33198886 PMCID: PMC7671685 DOI: 10.7554/elife.60970] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022] Open
Abstract
Second-generation antipsychotics are widely used to medicate patients with schizophrenia, but may cause metabolic side effects such as diabetes, which has been considered to result from obesity-associated insulin resistance. Olanzapine is particularly well known for this effect. However, clinical studies have suggested that olanzapine-induced hyperglycemia in certain patients cannot be explained by such a generalized mechanism. Here, we focused on the effects of olanzapine on insulin biosynthesis and secretion by mouse insulinoma MIN6 cells. Olanzapine reduced maturation of proinsulin, and thereby inhibited secretion of insulin; and specifically shifted the primary localization of proinsulin from insulin granules to the endoplasmic reticulum. This was due to olanzapine's impairment of proper disulfide bond formation in proinsulin, although direct targets of olanzapine remain undetermined. Olanzapine-induced proinsulin misfolding and subsequent decrease also occurred at the mouse level. This mechanism of olanzapine-induced β-cell dysfunction should be considered, together with weight gain, when patients are administered olanzapine.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Seiichiro Tada
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masaki Okumura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Kenta Inoguchi
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Misaki Kinoshita
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Shingo Kanemura
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan.,School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Koshi Imami
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hajime Umezawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Tokiro Ishikawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Robert B Mackin
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, United States
| | - Seiji Torii
- Laboratory of Secretion Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Yasushi Ishihama
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Takayuki Anazawa
- Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
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15
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Li N, Luo X, Yu Q, Yang P, Chen Z, Wang X, Jiang J, Xu J, Gong Q, Eizirik DL, Zhou Z, Zhao J, Xiong F, Zhang S, Wang CY. SUMOylation of Pdia3 exacerbates proinsulin misfolding and ER stress in pancreatic beta cells. J Mol Med (Berl) 2020; 98:1795-1807. [PMID: 33159537 DOI: 10.1007/s00109-020-02006-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/16/2020] [Accepted: 10/30/2020] [Indexed: 12/18/2022]
Abstract
SUMOylation has long been recognized to regulate multiple biological processes in pancreatic beta cells, but its impact on proinsulin disulfide maturation and endoplasmic reticulum (ER) stress remains elusive. Herein, we conducted comparative proteomic analyses of SUMOylated proteins in primary mouse/human islets following proinflammatory cytokine stimulation. Cytokine challenge rendered beta cells to undergo a SUMOylation turnover manifested by the changes of SUMOylation substrates and SUMOylation levels for multiple substrates. Our data support that SUMOylation may play a crucial role to regulate proinsulin misfolding and ER stress at least by targeting Protein Disulfide Isomerase a3 (Pdia3). SUMOylation regulates Pdia3 enzymatic activity, subcellular localization, and protein binding ability. Furthermore, SUMOylation of Pdia3 exacerbated proinsulin misfolding and ER stress, and repressed Stat3 activation. In contrast, disruption of Pdia3 SUMOylation markedly rescued the outcomes. Collectively, our study expands the understanding how SUMOylation regulates ER stress in beta cells, which shed light on developing potential strategies against beta cell dysfunction.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Xi Luo
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Qilin Yu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Ping Yang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Zhishui Chen
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Xinqiang Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jipin Jiang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jing Xu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Quan Gong
- Clinical Molecular Immunology Center, Department of Immunology, School of Medicine, Yangtze University, Jingzhou, 434023, China
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 808 Route de Lennik, B-1070, Brussels, Belgium.,Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, USA
| | - Zhiguang Zhou
- Diabetes Center, the Second Xiangya Hospital, Institute of Metabolism and Endocrinology, Central South University, Changsha, China
| | - Jiajun Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Fei Xiong
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Shu Zhang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
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16
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Patel C, Saad H, Shenkman M, Lederkremer GZ. Oxidoreductases in Glycoprotein Glycosylation, Folding, and ERAD. Cells 2020; 9:cells9092138. [PMID: 32971745 PMCID: PMC7563561 DOI: 10.3390/cells9092138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/17/2022] Open
Abstract
N-linked glycosylation and sugar chain processing, as well as disulfide bond formation, are among the most common post-translational protein modifications taking place in the endoplasmic reticulum (ER). They are essential modifications that are required for membrane and secretory proteins to achieve their correct folding and native structure. Several oxidoreductases responsible for disulfide bond formation, isomerization, and reduction have been shown to form stable, functional complexes with enzymes and chaperones that are involved in the initial addition of an N-glycan and in folding and quality control of the glycoproteins. Some of these oxidoreductases are selenoproteins. Recent studies also implicate glycan machinery–oxidoreductase complexes in the recognition and processing of misfolded glycoproteins and their reduction and targeting to ER-associated degradation. This review focuses on the intriguing cooperation between the glycoprotein-specific cell machineries and ER oxidoreductases, and highlights open questions regarding the functions of many members of this large family.
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Affiliation(s)
- Chaitanya Patel
- The Shmunis School of Biomedicine and Cancer Research, Cell Biology Division, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; (C.P.); (H.S.); (M.S.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Haddas Saad
- The Shmunis School of Biomedicine and Cancer Research, Cell Biology Division, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; (C.P.); (H.S.); (M.S.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Marina Shenkman
- The Shmunis School of Biomedicine and Cancer Research, Cell Biology Division, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; (C.P.); (H.S.); (M.S.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gerardo Z. Lederkremer
- The Shmunis School of Biomedicine and Cancer Research, Cell Biology Division, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; (C.P.); (H.S.); (M.S.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Correspondence:
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17
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Shrestha N, Reinert RB, Qi L. Endoplasmic Reticulum Protein Quality Control in β Cells. Semin Cell Dev Biol 2020; 103:59-67. [PMID: 32402517 PMCID: PMC7321887 DOI: 10.1016/j.semcdb.2020.04.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/17/2020] [Accepted: 04/10/2020] [Indexed: 12/12/2022]
Abstract
Type 1 and type 2 diabetes are associated with loss of β cell function. Optimal β cell function is linked to protein homeostasis in the endoplasmic reticulum (ER). Here, we review the roles of ER protein quality-control mechanisms, including the unfolded protein response (UPR), autophagy (specifically ER-phagy) and ER-associated degradation (ERAD), in β cells. We propose that different quality control mechanisms may control different aspects of β cell biology (i.e. function, survival, and identity), thereby contributing to disease pathogenesis.
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Affiliation(s)
- Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Rachel B Reinert
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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18
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Moilanen A, Ruddock LW. Non-native proteins inhibit the ER oxidoreductin 1 (Ero1)-protein disulfide-isomerase relay when protein folding capacity is exceeded. J Biol Chem 2020; 295:8647-8655. [PMID: 32102847 PMCID: PMC7324491 DOI: 10.1074/jbc.ra119.011766] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Protein maturation in the endoplasmic reticulum (ER) depends on a fine balance between oxidative protein folding and quality control mechanisms, which together ensure high-capacity export of properly folded proteins from the ER. Oxidative protein folding needs to be regulated to avoid hyperoxidation. The folding capacity of the ER is regulated by the unfolded protein response (UPR) and ER-associated degradation (ERAD). The UPR is triggered by unfolded protein stress and leads to up-regulation of cellular components such as chaperones and folding catalysts. These components relieve stress by increasing folding capacity and up-regulating ERAD components that remove non-native proteins. Although oxidative protein folding and the UPR/ERAD pathways each are well-understood, very little is known about any direct cross-talk between them. In this study, we carried out comprehensive in vitro activity and binding assays, indicating that the oxidative protein folding relay formed by ER oxidoreductin 1 (Ero1), and protein disulfide-isomerase can be inactivated by a feedback inhibition mechanism involving unfolded proteins and folding intermediates when their levels exceed the folding capacity of the system. This mechanism allows client proteins to remain mainly in the reduced state and thereby minimizes potential futile oxidation–reduction cycles and may also enhance ERAD, which requires reduced protein substrates. Relief from excess levels of non-native proteins by increasing the levels of folding factors removed the feedback inhibition. These results reveal regulatory cross-talk between the oxidative protein folding and UPR and ERAD pathways.
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Affiliation(s)
- Antti Moilanen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220 Oulu, Finland
| | - Lloyd W Ruddock
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220 Oulu, Finland.
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19
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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: 0.8] [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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20
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Imai J, Otani M, Sakai T. Distinct Subcellular Compartments of Dendritic Cells Used for Cross-Presentation. Int J Mol Sci 2019; 20:ijms20225606. [PMID: 31717517 PMCID: PMC6888166 DOI: 10.3390/ijms20225606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/29/2019] [Accepted: 11/06/2019] [Indexed: 02/06/2023] Open
Abstract
Dendritic cells (DCs) present exogenous protein-derived peptides on major histocompatibility complex class I molecules to prime naïve CD8+ T cells. This DC specific ability, called cross-presentation (CP), is important for the activation of cell-mediated immunity and the induction of self-tolerance. Recent research revealed that endoplasmic reticulum-associated degradation (ERAD), which was first identified as a part of the unfolded protein response—a quality control system in the ER—plays a pivotal role in the processing of exogenous proteins in CP. Moreover, DCs express a variety of immuno-modulatory molecules and cytokines to regulate T cell activation in response to the environment. Although both CP and immuno-modulation are indispensable, contrasting ER conditions are required for their correct activity. Since ERAD substrates are unfolded proteins, their accumulation may result in ER stress, impaired cell homeostasis, and eventually apoptosis. In contrast, activation of the unfolded protein response should be inhibited for DCs to express immuno-modulatory molecules and cytokines. Here, we review recent advances on antigen CP, focusing on intracellular transport routes for exogenous antigens and distinctive subcellular compartments involved in ERAD.
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Affiliation(s)
- Jun Imai
- Correspondence: ; Tel.: +81-27-352-1180
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21
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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: 9] [Impact Index Per Article: 1.8] [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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22
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Jang I, Pottekat A, Poothong J, Yong J, Lagunas-Acosta J, Charbono A, Chen Z, Scheuner DL, Liu M, Itkin-Ansari P, Arvan P, Kaufman RJ. PDIA1/P4HB is required for efficient proinsulin maturation and ß cell health in response to diet induced obesity. eLife 2019; 8:e44528. [PMID: 31184304 PMCID: PMC6559792 DOI: 10.7554/elife.44528] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/15/2019] [Indexed: 02/06/2023] Open
Abstract
Regulated proinsulin biosynthesis, disulfide bond formation and ER redox homeostasis are essential to prevent Type two diabetes. In ß cells, protein disulfide isomerase A1 (PDIA1/P4HB), the most abundant ER oxidoreductase of over 17 members, can interact with proinsulin to influence disulfide maturation. Here we find Pdia1 is required for optimal insulin production under metabolic stress in vivo. ß cell-specific Pdia1 deletion in young high-fat diet fed mice or aged mice exacerbated glucose intolerance with inadequate insulinemia and increased the proinsulin/insulin ratio in both serum and islets compared to wildtype mice. Ultrastructural abnormalities in Pdia1-null ß cells include diminished insulin granule content, ER vesiculation and distention, mitochondrial swelling and nuclear condensation. Furthermore, Pdia1 deletion increased accumulation of disulfide-linked high molecular weight proinsulin complexes and islet vulnerability to oxidative stress. These findings demonstrate that PDIA1 contributes to oxidative maturation of proinsulin in the ER to support insulin production and ß cell health.
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Affiliation(s)
- Insook Jang
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | - Anita Pottekat
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | - Juthakorn Poothong
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | - Jing Yong
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | | | - Adriana Charbono
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | - Zhouji Chen
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
| | | | - Ming Liu
- Division of Metabolism Endocrinology and DiabetesUniversity of Michigan Medical SchoolAnn ArborUnited States
| | - Pamela Itkin-Ansari
- Department of PediatricsUniversity of California, San DiegoSan DiegoUnited States
| | - Peter Arvan
- Division of Metabolism Endocrinology and DiabetesUniversity of Michigan Medical SchoolAnn ArborUnited States
| | - Randal J Kaufman
- Degenerative Diseases ProgramSBP Medical Discovery InstituteLa JollaUnited States
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23
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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: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [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.
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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.
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24
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Fregno I, Molinari M. Proteasomal and lysosomal clearance of faulty secretory proteins: ER-associated degradation (ERAD) and ER-to-lysosome-associated degradation (ERLAD) pathways. Crit Rev Biochem Mol Biol 2019; 54:153-163. [PMID: 31084437 DOI: 10.1080/10409238.2019.1610351] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
About 40% of the eukaryotic cell's proteins are inserted co- or post-translationally in the endoplasmic reticulum (ER), where they attain the native structure under the assistance of resident molecular chaperones and folding enzymes. Subsequently, these proteins are secreted from cells or are transported to their sites of function at the plasma membrane or in organelles of the secretory and endocytic compartments. Polypeptides that are not delivered within the ER (mis-localized proteins, MLPs) are rapidly destroyed by cytosolic proteasomes, with intervention of the membrane protease ZMPSTE24 if they remained trapped in the SEC61 translocation machinery. Proteins that enter the ER, but fail to attain the native structure are rapidly degraded to prevent toxic accumulation of aberrant gene products. The ER does not contain degradative devices and the majority of misfolded proteins generated in this biosynthetic compartment are dislocated across the membrane for degradation by cytosolic 26S proteasomes by mechanisms and pathways collectively defined as ER-associated degradation (ERAD). Proteins that do not engage ERAD factors, that enter aggregates or polymers, are too large, display chimico/physical features that prevent dislocation across the ER membrane (ERAD-resistant misfolded proteins) are delivered to endo-lysosome for clearance, by mechanisms and pathways collectively defined as ER-to-lysosomes-associated degradation (ERLAD). Emerging evidences lead us to propose ERLAD as an umbrella term that includes the autophagic and non-autophagic pathways activated and engaged by ERAD-resistant misfolded proteins generated in the ER for delivery to degradative endo-lysosomes.
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Affiliation(s)
- Ilaria Fregno
- a Institute for Research in Biomedicine, Faculty of Biomedical Sciences , Università della Svizzera italiana (USI) , Bellinzona , Switzerland
| | - Maurizio Molinari
- a Institute for Research in Biomedicine, Faculty of Biomedical Sciences , Università della Svizzera italiana (USI) , Bellinzona , Switzerland.,b School of Life Sciences , École Polytechnique Fédérale de Lausanne , Lausanne , Switzerland
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25
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Huang H, Yang K, Wang R, Han WH, Kuny S, Zelmanovitz PH, Sauvé Y, Chan CB. β-Cell compensation concomitant with adaptive endoplasmic reticulum stress and β-cell neogenesis in a diet-induced type 2 diabetes model. Appl Physiol Nutr Metab 2019; 44:1355-1366. [PMID: 31082326 DOI: 10.1139/apnm-2019-0144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Insulin-secreting pancreatic β-cells adapt to obesity-related insulin resistance via increases in insulin secretion and β-cell mass. Failed β-cell compensation predicts the onset of type 2 diabetes (T2D). However, the mechanisms of β-cell compensation are not fully understood. Our previous study reported changes in β-cell mass during the progression of T2D in the Nile rat (NR; Arvicanthis niloticus) fed standard chow. In the present study, we measured other β-cell adaptive responses, including glucose metabolism and β-cell insulin secretion in NRs at different ages, thus characterizing NR at 2 months as a model of β-cell compensation followed by decompensation at 6 months. We observed increased proinsulin secretion in the transition from compensation to decompensation, which is indicative of impaired insulin processing. Subsequently, we compared adaptive unfolded protein response in β-cells and demonstrated a positive role of endoplasmic reticulum (ER) chaperones in insulin secretion. In addition, the incidence of insulin-positive neogenic but not proliferative cells increased during the compensation phase, suggesting nonproliferative β-cell growth as a mechanism of β-cell mass adaptation. In contrast, decreased neogenesis and β-cell dedifferentiation were observed in β-cell dysfunction. Furthermore, the progression of T2D and pathophysiological changes of β-cells were prevented by increasing fibre content of the diet. Novelty Our study characterized a novel model for β-cell compensation with adaptive responses in cell function and mass. The temporal association of adaptive ER chaperones with blood insulin and glucose suggests upregulated chaperone capacity as an adaptive mechanism. β-Cell neogenesis but not proliferation contributes to β-cell mass adaptation.
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Affiliation(s)
- Hui Huang
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Kaiyuan Yang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Rennian Wang
- Children's Health Research Institute, London, ON N6C 2V5, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Woo Hyun Han
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, AB T5H 3V9, Canada
| | - Sharee Kuny
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, AB T5H 3V9, Canada
| | | | - Yves Sauvé
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada.,Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, AB T5H 3V9, Canada
| | - Catherine B Chan
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada.,Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
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26
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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: 118] [Impact Index Per Article: 19.7] [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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27
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The reductase TMX1 contributes to ERAD by preferentially acting on membrane-associated folding-defective polypeptides. Biochem Biophys Res Commun 2018; 503:938-943. [DOI: 10.1016/j.bbrc.2018.06.099] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/19/2018] [Indexed: 11/22/2022]
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28
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Xu B, Allard C, Alvarez-Mercado AI, Fuselier T, Kim JH, Coons LA, Hewitt SC, Urano F, Korach KS, Levin ER, Arvan P, Floyd ZE, Mauvais-Jarvis F. Estrogens Promote Misfolded Proinsulin Degradation to Protect Insulin Production and Delay Diabetes. Cell Rep 2018; 24:181-196. [PMID: 29972779 PMCID: PMC6092934 DOI: 10.1016/j.celrep.2018.06.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/11/2018] [Accepted: 06/01/2018] [Indexed: 02/06/2023] Open
Abstract
Conjugated estrogens (CE) delay the onset of type 2 diabetes (T2D) in postmenopausal women, but the mechanism is unclear. In T2D, the endoplasmic reticulum (ER) fails to promote proinsulin folding and, in failing to do so, promotes ER stress and β cell dysfunction. We show that CE prevent insulin-deficient diabetes in male and in female Akita mice using a model of misfolded proinsulin. CE stabilize the ER-associated protein degradation (ERAD) system and promote misfolded proinsulin proteasomal degradation. This involves activation of nuclear and membrane estrogen receptor-α (ERα), promoting transcriptional repression and proteasomal degradation of the ubiquitin-conjugating enzyme and ERAD degrader, UBC6e. The selective ERα modulator bazedoxifene mimics CE protection of β cells in females but not in males.
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Affiliation(s)
- Beibei Xu
- Diabetes Discovery Research and Gender Medicine Laboratory, Department of Medicine, Section of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Camille Allard
- Diabetes Discovery Research and Gender Medicine Laboratory, Department of Medicine, Section of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Ana I Alvarez-Mercado
- Diabetes Discovery Research and Gender Medicine Laboratory, Department of Medicine, Section of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Taylor Fuselier
- Diabetes Discovery Research and Gender Medicine Laboratory, Department of Medicine, Section of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System Medical Center, New Orleans, LA 70112, USA
| | - Jun Ho Kim
- Department of Food Science and Biotechnology, Andong National University, Andong, Gyeongsangbuk-do 36729, South Korea
| | - Laurel A Coons
- Receptor Biology Section, Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, Durham, NC 27709, USA; Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sylvia C Hewitt
- Receptor Biology Section, Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, Durham, NC 27709, USA
| | - Fumihiko Urano
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kenneth S Korach
- Receptor Biology Section, Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, Durham, NC 27709, USA
| | - Ellis R Levin
- Division of Endocrinology, Veterans Affairs Medical Center, Long Beach, CA 90822, USA; Departments of Medicine and Biochemistry, University of California, Irvine, Irvine, CA 92717, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Z Elizabeth Floyd
- Ubiquitin Lab, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70803, USA
| | - Franck Mauvais-Jarvis
- Diabetes Discovery Research and Gender Medicine Laboratory, Department of Medicine, Section of Endocrinology and Metabolism, School of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System Medical Center, New Orleans, LA 70112, USA.
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29
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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] [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.
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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
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30
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Ellgaard L, Sevier CS, Bulleid NJ. How Are Proteins Reduced in the Endoplasmic Reticulum? Trends Biochem Sci 2018; 43:32-43. [PMID: 29153511 PMCID: PMC5751730 DOI: 10.1016/j.tibs.2017.10.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 12/16/2022]
Abstract
The reversal of thiol oxidation in proteins within the endoplasmic reticulum (ER) is crucial for protein folding, degradation, chaperone function, and the ER stress response. Our understanding of this process is generally poor but progress has been made. Enzymes performing the initial reduction of client proteins, as well as the ultimate electron donor in the pathway, have been identified. Most recently, a role for the cytosol in ER protein reduction has been revealed. Nevertheless, how reducing equivalents are transferred from the cytosol to the ER lumen remains an open question. We review here why proteins are reduced in the ER, discuss recent data on catalysis of steps in the pathway, and consider the implications for redox homeostasis within the early secretory pathway.
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Affiliation(s)
- Lars Ellgaard
- Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Carolyn S Sevier
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-2703, USA.
| | - Neil J Bulleid
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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31
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Delaunay-Moisan A, Ponsero A, Toledano MB. Reexamining the Function of Glutathione in Oxidative Protein Folding and Secretion. Antioxid Redox Signal 2017; 27:1178-1199. [PMID: 28791880 DOI: 10.1089/ars.2017.7148] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
SIGNIFICANCE Disturbance of glutathione (GSH) metabolism is a hallmark of numerous diseases, yet GSH functions are poorly understood. One key to this question is to consider its functional compartmentation. GSH is present in the endoplasmic reticulum (ER), where it competes with substrates for oxidation by the oxidative folding machinery, composed in eukaryotes of the thiol oxidase Ero1 and proteins from the disulfide isomerase family (protein disulfide isomerase). Yet, whether GSH is required for proper ER oxidative protein folding is a highly debated question. Recent Advances: Oxidative protein folding has been thoroughly dissected over the past decades, and its actors and their mode of action elucidated. Genetically encoded GSH probes have recently provided an access to subcellular redox metabolism, including the ER. CRITICAL ISSUES Of the few often-contradictory models of the role of GSH in the ER, the most popular suggest it serves as reducing power. Yet, as a reductant, GSH also activates Ero1, which questions how GSH can nevertheless support protein reduction. Hence, whether GSH operates in the ER as a reductant, an oxidant, or just as a "blank" compound mirroring ER/periplasm redox activity is a highly debated question, which is further stimulated by the puzzling occurrence of GSH in the Escherichia coli periplasmic "secretory" compartment, aside from the Dsb thiol-reducing and oxidase pathways. FUTURE DIRECTIONS Addressing the mechanisms controlling GSH traffic in and out of the ER/periplasm and its recycling will help address GSH function in secretion. In addition, as thioredoxin reductase was recently implicated in ER oxidative protein folding, the relative contribution of each of these two reducing pathways should now be addressed. Antioxid. Redox Signal. 27, 1178-1199.
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Affiliation(s)
- Agnès Delaunay-Moisan
- Institute for Integrative Biology of the Cell (I2BC), LSOC, SBIGEM, CEA, CNRS, Université Paris-Sud , Université Paris-Saclay, Gif-sur-Yvette, France
| | - Alise Ponsero
- Institute for Integrative Biology of the Cell (I2BC), LSOC, SBIGEM, CEA, CNRS, Université Paris-Sud , Université Paris-Saclay, Gif-sur-Yvette, France
| | - Michel B Toledano
- Institute for Integrative Biology of the Cell (I2BC), LSOC, SBIGEM, CEA, CNRS, Université Paris-Sud , Université Paris-Saclay, Gif-sur-Yvette, France
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32
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Shi G, Somlo DRM, Kim GH, Prescianotto-Baschong C, Sun S, Beuret N, Long Q, Rutishauser J, Arvan P, Spiess M, Qi L. ER-associated degradation is required for vasopressin prohormone processing and systemic water homeostasis. J Clin Invest 2017; 127:3897-3912. [PMID: 28920920 DOI: 10.1172/jci94771] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/26/2017] [Indexed: 12/11/2022] Open
Abstract
Peptide hormones are crucial regulators of many aspects of human physiology. Mutations that alter these signaling peptides are associated with physiological imbalances that underlie diseases. However, the conformational maturation of peptide hormone precursors (prohormones) in the ER remains largely unexplored. Here, we report that conformational maturation of proAVP, the precursor for the antidiuretic hormone arginine-vasopressin, within the ER requires the ER-associated degradation (ERAD) activity of the Sel1L-Hrd1 protein complex. Serum hyperosmolality induces expression of both ERAD components and proAVP in AVP-producing neurons. Mice with global or AVP neuron-specific ablation of Se1L-Hrd1 ERAD progressively developed polyuria and polydipsia, characteristics of diabetes insipidus. Mechanistically, we found that ERAD deficiency causes marked ER retention and aggregation of a large proportion of all proAVP protein. Further, we show that proAVP is an endogenous substrate of Sel1L-Hrd1 ERAD. The inability to clear misfolded proAVP with highly reactive cysteine thiols in the absence of Sel1L-Hrd1 ERAD causes proAVP to accumulate and participate in inappropriate intermolecular disulfide-bonded aggregates, promoted by the enzymatic activity of protein disulfide isomerase (PDI). This study highlights a pathway linking ERAD to prohormone conformational maturation in neuroendocrine cells, expanding the role of ERAD in providing a conducive ER environment for nascent proteins to reach proper conformation.
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Affiliation(s)
- Guojun Shi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Diane RM Somlo
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | - Geun Hyang Kim
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Shengyi Sun
- Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA
| | | | - Qiaoming Long
- Cam-Su Mouse Genomic Resources Center, Suzhou University, Suzhou, Jiangsu, China
| | | | - Peter Arvan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
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33
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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] [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.
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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
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Qi L, Tsai B, Arvan P. New Insights into the Physiological Role of Endoplasmic Reticulum-Associated Degradation. Trends Cell Biol 2017; 27:430-440. [PMID: 28131647 DOI: 10.1016/j.tcb.2016.12.002] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/04/2016] [Accepted: 12/23/2016] [Indexed: 12/13/2022]
Abstract
Many human diseases are associated with mutations causing protein misfolding and aggregation in the endoplasmic reticulum (ER). ER-associated degradation (ERAD) is a principal quality-control mechanism responsible for targeting misfolded ER proteins for cytosolic degradation. However, despite years of effort, the physiological role of ERAD in vivo remains largely unknown. Several recent studies have reported intriguing phenotypes of mice deficient for ERAD function in specific cell types. These studies highlight that mammalian ERAD has been designed to perform a wide-range of cell-type-specific functions in vivo in a substrate-dependent manner.
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Affiliation(s)
- Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Peter Arvan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
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35
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Poet GJ, Oka OB, van Lith M, Cao Z, Robinson PJ, Pringle MA, Arnér ES, Bulleid NJ. Cytosolic thioredoxin reductase 1 is required for correct disulfide formation in the ER. EMBO J 2017; 36:693-702. [PMID: 28093500 PMCID: PMC5331760 DOI: 10.15252/embj.201695336] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 11/09/2022] Open
Abstract
Folding of proteins entering the secretory pathway in mammalian cells frequently requires the insertion of disulfide bonds. Disulfide insertion can result in covalent linkages found in the native structure as well as those that are not, so-called non-native disulfides. The pathways for disulfide formation are well characterized, but our understanding of how non-native disulfides are reduced so that the correct or native disulfides can form is poor. Here, we use a novel assay to demonstrate that the reduction in non-native disulfides requires NADPH as the ultimate electron donor, and a robust cytosolic thioredoxin system, driven by thioredoxin reductase 1 (TrxR1 or TXNRD1). Inhibition of this reductive pathway prevents the correct folding and secretion of proteins that are known to form non-native disulfides during their folding. Hence, we have shown for the first time that mammalian cells have a pathway for transferring reducing equivalents from the cytosol to the ER, which is required to ensure correct disulfide formation in proteins entering the secretory pathway.
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Affiliation(s)
- Greg J Poet
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Ojore Bv Oka
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Marcel van Lith
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Zhenbo Cao
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Philip J Robinson
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Marie Anne Pringle
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
| | - Elias Sj Arnér
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, Stockholm, Sweden
| | - Neil J Bulleid
- The Institute of Molecular, Cell and Systems Biology, CMVLS, University of Glasgow, Glasgow, UK
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36
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Soares Moretti AI, Martins Laurindo FR. Protein disulfide isomerases: Redox connections in and out of the endoplasmic reticulum. Arch Biochem Biophys 2016; 617:106-119. [PMID: 27889386 DOI: 10.1016/j.abb.2016.11.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/08/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Protein disulfide isomerases are thiol oxidoreductase chaperones from thioredoxin superfamily. As redox folding catalysts from the endoplasmic reticulum (ER), their roles in ER-related redox homeostasis and signaling are well-studied. PDIA1 exerts thiol oxidation/reduction and isomerization, plus chaperone effects. Also, substantial evidence indicates that PDIs regulate thiol-disulfide switches in other cell locations such as cell surface and possibly cytosol. Subcellular PDI translocation routes remain unclear and seem Golgi-independent. The list of signaling and structural proteins reportedly regulated by PDIs keeps growing, via thiol switches involving oxidation, reduction and isomerization, S-(de)nytrosylation, (de)glutathyonylation and protein oligomerization. PDIA1 is required for agonist-triggered Nox NADPH oxidase activation and cell migration in vascular cells and macrophages, while PDIA1-dependent cytoskeletal regulation appears a converging pathway. Extracellularly, PDIs crucially regulate thiol redox signaling of thrombosis/platelet activation, e.g., integrins, and PDIA1 supports expansive caliber remodeling during injury repair via matrix/cytoskeletal organization. Some proteins display regulatory PDI-like motifs. PDI effects are orchestrated by expression levels or post-translational modifications. PDI is redox-sensitive, although probably not a mass-effect redox sensor due to kinetic constraints. Rather, the "all-in-one" organization of its peculiar redox/chaperone properties likely provide PDIs with precision and versatility in redox signaling, making them promising therapeutic targets.
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Affiliation(s)
- Ana Iochabel Soares Moretti
- Vascular Biology Laboratory, Heart Institute (InCor), University of São Paulo, School of Medicine, São Paulo, Brazil
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37
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Gorasia DG, Dudek NL, Safavi-Hemami H, Perez RA, Schittenhelm RB, Saunders PM, Wee S, Mangum JE, Hubbard MJ, Purcell AW. A prominent role of PDIA6 in processing of misfolded proinsulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:715-723. [PMID: 26947243 DOI: 10.1016/j.bbapap.2016.03.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 02/22/2016] [Accepted: 03/02/2016] [Indexed: 11/17/2022]
Abstract
Despite its critical role in maintaining glucose homeostasis, surprisingly little is known about proinsulin folding in the endoplasmic reticulum. In this study we aimed to understand the chaperones involved in the maturation and degradation of proinsulin. We generated pancreatic beta cell lines expressing FLAG-tagged proinsulin. Several chaperones (including BiP, PDIA6, calnexin, calreticulin, GRP170, Erdj3 and ribophorin II) co-immunoprecipitated with proinsulin suggesting a role for these proteins in folding. To investigate the chaperones responsible for targeting misfolded proinsulin for degradation, we also created a beta cell line expressing FLAG-tagged proinsulin carrying the Akita mutation (Cys96Tyr). All chaperones found to be associated with wild type proinsulin also co-immunoprecipitated with Akita proinsulin. However, one additional protein, namely P58(IPK), specifically precipitated with Akita proinsulin and approximately ten fold more PDIA6, but not other PDI family members, was bound to Akita proinsulin. The latter suggests that PDIA6 may act as a key reductase and target misfolded proinsulin to the ER-degradation pathway. The preferential association of PDIA6 to Akita proinsulin was also confirmed in another beta cell line (βTC-6). Furthermore, for the first time, a physiologically relevant substrate for PDIA6 has been evidenced. Thus, this study has identified several chaperones/foldases that associated with wild type proinsulin and has also provided a comprehensive interactome for Akita misfolded proinsulin.
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Affiliation(s)
- Dhana G Gorasia
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Nadine L Dudek
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia; Infection and Immunity Program, Biomolecular Discovery Institute and Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Helena Safavi-Hemami
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Rochelle Ayala Perez
- Infection and Immunity Program, Biomolecular Discovery Institute and Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Ralf B Schittenhelm
- Infection and Immunity Program, Biomolecular Discovery Institute and Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Philippa M Saunders
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sheena Wee
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Jon E Mangum
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Michael J Hubbard
- Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anthony W Purcell
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia; Infection and Immunity Program, Biomolecular Discovery Institute and Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia.
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