101
|
Onda Y, Kawagoe Y. Oxidative protein folding: selective pressure for prolamin evolution in rice. PLANT SIGNALING & BEHAVIOR 2011; 6:1966-72. [PMID: 22112460 PMCID: PMC3337189 DOI: 10.4161/psb.6.12.17967] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
During seed development, endosperm cells of highly productive cereals, including rice, synthesize disulfide-rich proteins in large amounts and deposit them into storage organelles. Disulfide bond formation involves electron transfer and generates H(2)O(2) as a by-product. To ensure proper development and maturation of seeds, the endosperm cells must supply large amounts of oxidizing equivalents to dithiols in nascent proteins in a controlled manner. This review compares multiple oxidative protein folding systems in yeast, cultured human cells, and rice endosperm. We discuss possible roles of ERO1, other sulfhydryl oxidases, and the protein disulfide isomerase family in the formation of disulfide bonds in storage proteins and the development of protein bodies. Rice prolamins, encoded by a multigene family, are divided into Cys-rich and Cys-depleted subgroups. We discuss the potential importance of disulfide bond formation in the evolution of the prolamin family in japonica rice.
Collapse
Affiliation(s)
- Yayoi Onda
- Department of Food and Applied Life Sciences; Yamagata University; Tsuruoka, Japan
| | - Yasushi Kawagoe
- Division of Plant Sciences; National Institute of Agrobiological Sciences; Tsukuba, Japan
| |
Collapse
|
102
|
Human herpesvirus 8 viral interleukin-6 interacts with splice variant 2 of vitamin K epoxide reductase complex subunit 1. J Virol 2011; 86:1577-88. [PMID: 22130532 DOI: 10.1128/jvi.05782-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral interleukin-6 (vIL-6) specified by human herpesvirus 8 is, unlike its cellular counterpart, secreted very inefficiently and can signal via vIL-6(2):gp130(2) signaling complexes from the endoplasmic reticulum (ER) compartment. Intracellular, autocrine activities of vIL-6 are important for proproliferative and prosurvival activities of the viral cytokine in latently infected primary effusion lymphoma (PEL) cells. However, the molecular determinants of vIL-6 ER localization and function are unclear. Using yeast two-hybrid analysis, we identified the database-documented but uncharacterized splice variant of vitamin K epoxide reductase complex subunit 1 (VKORC1), termed VKORC1 variant 2 (VKORC1v2), as a potential interaction partner of vIL-6. In transfected cells, epitope-tagged VKORC1v2 was found to localize to the ER, to adopt a single-transmembrane (TM) topology placing the C tail in the ER lumen, and to bind vIL-6 via these sequences. Deletion mutagenesis and coprecipitation assays mapped the vIL-6-binding domain (vBD) of VKORC1v2 to TM-proximal residues 31 to 39. However, while sufficient to confer vIL-6 binding to a heterologous protein, vBD was unable to induce vIL-6 secretion when fused to (secreted) hIL-6, suggesting a VKORC1v2-independent mechanism of vIL-6 ER retention. In functional assays, overexpression of ER-directed vBD led to suppression of PEL cell proliferation and viability, effects also mediated by VKORC1v2 depletion and, as reported previously, by vIL-6 suppression. The growth-inhibitory and proapoptotic effects of VKORC1v2 depletion could be rescued by transduced wild-type VKORC1v2 but not by a vIL-6-refractory vBD-altered variant, indicating the functional relevance of the vIL-6-VKORC1v2 interaction. Notably, gp130 signaling was unaffected by VKORC1v2 or vBD overexpression or by VKORC1v2 depletion, suggesting an alternative pathway of vIL-6 activity via VKORC1v2. Combined, our data identify a novel and functionally significant interaction partner of vIL-6 that could potentially be targeted for therapeutic benefit.
Collapse
|
103
|
Rajpal G, Schuiki I, Liu M, Volchuk A, Arvan P. Action of protein disulfide isomerase on proinsulin exit from endoplasmic reticulum of pancreatic β-cells. J Biol Chem 2011; 287:43-47. [PMID: 22105075 DOI: 10.1074/jbc.c111.279927] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For insulin synthesis, the proinsulin precursor is translated at the endoplasmic reticulum (ER), folds to include its three native disulfide bonds, and is exported to secretory granules for processing and secretion. Protein disulfide isomerase (PDI) has long been assumed to assist proinsulin in this process. Herein we have examined the effect of PDI knockdown (PDI-KD) in β-cells. The data establish that upon PDI-KD, oxidation of proinsulin to form native disulfide bonds is unimpaired and in fact enhanced. This is accompanied by improved proinsulin exit from the ER and increased total insulin secretion, with no evidence of ER stress. We provide evidence for direct physical interaction between PDI and proinsulin in the ER of pancreatic β-cells, in a manner requiring the catalytic activity of PDI. In β-cells after PDI-KD, enhanced export is selective for proinsulin over other secretory proteins, but the same effect is observed for recombinant proinsulin trafficking upon PDI-KD in heterologous cells. We hypothesize that PDI exhibits unfoldase activity for proinsulin, increasing retention of proinsulin within the ER of pancreatic β-cells.
Collapse
Affiliation(s)
- Gautam Rajpal
- Division of Metabolism, Endocrinology and Diabetes and the Cellular and Molecular Biology Program, University of Michigan Medical Center, Ann Arbor, Michigan 48105-51714
| | - Irmgard Schuiki
- Division of Cellular and Molecular Biology, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada
| | - Ming Liu
- Division of Metabolism, Endocrinology and Diabetes and the Cellular and Molecular Biology Program, University of Michigan Medical Center, Ann Arbor, Michigan 48105-51714
| | - Allen Volchuk
- Division of Cellular and Molecular Biology, Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 2M9, Canada
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes and the Cellular and Molecular Biology Program, University of Michigan Medical Center, Ann Arbor, Michigan 48105-51714.
| |
Collapse
|
104
|
Warfarin and acetaminophen interaction: a summary of the evidence and biologic plausibility. Blood 2011; 118:6269-73. [PMID: 21911832 DOI: 10.1182/blood-2011-08-335612] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ms TS is a 66-year-old woman who receives warfarin for prevention of systemic embolization in the setting of hypertension, diabetes, and atrial fibrillation. She had a transient ischemic attack about 4 years ago when she was receiving aspirin. Her INR control was excellent; however, over the past few months it has become erratic, and her average dose required to maintain an INR of 2.0 to 3.0 appears to have decreased. She has had back pain over this same period and has been taking acetaminophen at doses at large as 650 mg four times daily, with her dose varying based on her symptoms. You recall a potential interaction and wonder if (1) her acetaminophen use is contributing to her loss of INR control, and (2) does this interaction place her at increased risk of warfarin-related complications?
Collapse
|
105
|
Biochemical characterization of spontaneous mutants of rat VKORC1 involved in the resistance to antivitamin K anticoagulants. Arch Biochem Biophys 2011; 515:14-20. [PMID: 21907178 DOI: 10.1016/j.abb.2011.08.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 08/24/2011] [Accepted: 08/25/2011] [Indexed: 11/23/2022]
Abstract
Antivitamin K anticoagulants have been commonly used to control rodent pest all over the world for more than 50 years. These compounds target blood coagulation by inhibiting the vitamin K epoxide reductase (VKORC1), which catalyzes the reduction of vitamin K 2,3-epoxide to vitamin K. Resistance to anticoagulants has been reported in wild rat populations from different countries. From these populations, several mutations of the rVkorc1 gene have been reported. In this study, rat VKORC1 and its most frequent mutants L120Q-, L128Q-, Y139C-, Y139S- and Y139F-VKORC1 were expressed as membrane-bound proteins in Pichia pastoris and characterized by the determination of kinetic and inhibition parameters. The recombinant rVKORC1 showed similar properties than those of the native proteins expressed in the rat liver microsomes, validating the expression system as a good model to study the consequences of VKORC1 mutations. The determination of the inhibition parameters towards various antivitamin K anticoagulants demonstrated that mutations at Leu-120, Leu-128 and Tyr-139 confer the resistance to the first generation AVKs observed in wild rat populations.
Collapse
|
106
|
Bulleid NJ, Ellgaard L. Multiple ways to make disulfides. Trends Biochem Sci 2011; 36:485-92. [PMID: 21778060 DOI: 10.1016/j.tibs.2011.05.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/13/2011] [Accepted: 05/24/2011] [Indexed: 12/16/2022]
Abstract
Our concept of how disulfides form in proteins entering the secretory pathway has changed dramatically in recent years. The discovery of endoplasmic reticulum (ER) oxidoreductin 1 (ERO1) was followed by the demonstration that this enzyme couples oxygen reduction to de novo formation of disulfides. However, mammals deficient in ERO1 survive and form disulfides, which suggests the presence of alternative pathways. It has recently been shown that peroxiredoxin 4 is involved in peroxide removal and disulfide formation. Other less well-characterized pathways involving quiescin sulfhydryl oxidase, ER-localized protein disulfide isomerase peroxidases and vitamin K epoxide reductase might all contribute to disulfide formation. Here we discuss these various pathways for disulfide formation in the mammalian ER and highlight the central role played by glutathione in regulating this process.
Collapse
Affiliation(s)
- Neil J Bulleid
- Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | | |
Collapse
|
107
|
van Lith M, Tiwari S, Pediani J, Milligan G, Bulleid NJ. Real-time monitoring of redox changes in the mammalian endoplasmic reticulum. J Cell Sci 2011; 124:2349-56. [PMID: 21693587 DOI: 10.1242/jcs.085530] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Redox-sensitive GFPs with engineered disulphide bonds have been used previously to monitor redox status in the cytosol and mitochondria of living cells. The usefulness of these redox probes depends on the reduction potential of the disulphide, with low values suiting the cytosol and mitochondrion, and higher values suiting the more oxidising environment of the endoplasmic reticulum (ER). Here, we targeted a modified redox-sensitive GFP (roGFP1-iL), with a relatively high reduction potential, to the ER of mammalian cells. We showed that the disulphide is partially oxidised, allowing roGFP1-iL to monitor changes in ER redox status. When cells were treated with puromycin, the redox balance became more reducing, suggesting that the release of nascent chains from ribosomes alters the ER redox balance. In addition, downregulating Ero1α prevented normal rapid recovery from dithiothreitol (DTT), whereas downregulating peroxiredoxin IV had no such effect. This result illustrates the contribution of the Ero1α oxidative pathway to ER redox balance. This first report of the use of roGFP to study the ER of mammalian cells demonstrates that roGFP1-iL can be used to monitor real-time changes to the redox status in individual living cells.
Collapse
Affiliation(s)
- Marcel van Lith
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | | | | | | | | |
Collapse
|
108
|
Appenzeller-Herzog C. Glutathione- and non-glutathione-based oxidant control in the endoplasmic reticulum. J Cell Sci 2011; 124:847-55. [PMID: 21378306 DOI: 10.1242/jcs.080895] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The redox-active tripeptide glutathione is an endogenous reducing agent that is found in abundance and throughout the cell. In the endoplasmic reticulum (ER), the ratio of glutathione to glutathione disulfide is lower compared with non-secretory organelles. This relatively oxidizing thiol-disulfide milieu is essential for the oxidative folding of nascent proteins in the ER and, at least in part, maintained by the activity of ER-resident endoplasmic oxidoreductin 1 (Ero1) enzymes that oxidize cysteine side chains at the expense of molecular oxygen. Glutathione disulfide and hydrogen peroxide formed as a consequence of Ero1 activity are widely considered as being inoperative and potentially dangerous by-products of oxidative protein folding in the ER. In contrast to this common view, this Commentary highlights the importance of glutathione- and non glutathione-based homeostatic redox control mechanisms in the ER. Stability in the thiol-disulfide system that prominently includes the protein disulfide isomerases is ensured by the contribution of tightly regulated Ero1 activity, ER-resident peroxidases and the glutathione-glutathione-disulfide redox pair that acts as a potent housekeeper of redox balance. Accordingly, the widely held concept that Ero1-mediated over-oxidation in the ER constitutes a common cause of cellular demise is critically re-evaluated.
Collapse
Affiliation(s)
- Christian Appenzeller-Herzog
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstr. 50, CH-4056 Basel, Switzerland.
| |
Collapse
|
109
|
Wu S, Liu S, Davis CH, Stafford DW, Kulman JD, Pedersen LG. A hetero-dimer model for concerted action of vitamin K carboxylase and vitamin K reductase in vitamin K cycle. J Theor Biol 2011; 279:143-9. [PMID: 21453708 DOI: 10.1016/j.jtbi.2011.03.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/23/2011] [Accepted: 03/23/2011] [Indexed: 10/18/2022]
Abstract
Vitamin K carboxylase (VKC) is believed to convert vitamin K, in the vitamin K cycle, to an alkoxide-epoxide form which then reacts with CO(2) and glutamate to generate γ-carboxyglutamic acid (Gla). Subsequently, vitamin K epoxide reductase (VKOR) is thought to convert the alkoxide-epoxide to a hydroquinone form. By recycling vitamin K, the two integral-membrane proteins, VKC and VKOR, maintain vitamin K levels and sustain the blood coagulation cascade. Unfortunately, NMR or X-ray crystal structures of the two proteins have not been characterized. Thus, our understanding of the vitamin K cycle is only partial at the molecular level. In this study, based on prior biochemical experiments on VKC and VKOR, we propose a hetero-dimeric form of VKC and VKOR that may explain the efficient oxidation and reduction of vitamin K during the vitamin K cycle.
Collapse
Affiliation(s)
- Sangwook Wu
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
| | | | | | | | | | | |
Collapse
|
110
|
Westhofen P, Watzka M, Marinova M, Hass M, Kirfel G, Müller J, Bevans CG, Müller CR, Oldenburg J. Human vitamin K 2,3-epoxide reductase complex subunit 1-like 1 (VKORC1L1) mediates vitamin K-dependent intracellular antioxidant function. J Biol Chem 2011; 286:15085-94. [PMID: 21367861 DOI: 10.1074/jbc.m110.210971] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Human vitamin K 2,3-epoxide reductase complex subunit 1-like 1 (VKORC1L1), expressed in HEK 293T cells and localized exclusively to membranes of the endoplasmic reticulum, was found to support both vitamin K 2,3-epoxide reductase (VKOR) and vitamin K reductase enzymatic activities. Michaelis-Menten kinetic parameters for dithiothreitol-driven VKOR activity were: K(m) (μM) = 4.15 (vitamin K(1) epoxide) and 11.24 (vitamin K(2) epoxide); V(max) (nmol·mg(-1)·hr(-1)) = 2.57 (vitamin K(1) epoxide) and 13.46 (vitamin K(2) epoxide). Oxidative stress induced by H(2)O(2) applied to cultured cells up-regulated VKORC1L1 expression and VKOR activity. Cell viability under conditions of no induced oxidative stress was increased by the presence of vitamins K(1) and K(2) but not ubinquinone-10 and was specifically dependent on VKORC1L1 expression. Intracellular reactive oxygen species levels in cells treated with 2,3-dimethoxy-1,4-naphthoquinone were mitigated in a VKORC1L1 expression-dependent manner. Intracellular oxidative damage to membrane intrinsic proteins was inversely dependent on VKORC1L1 expression and the presence of vitamin K(1). Taken together, our results suggest that VKORC1L1 is responsible for driving vitamin K-mediated intracellular antioxidation pathways critical to cell survival.
Collapse
Affiliation(s)
- Philipp Westhofen
- Institute of Experimental Hematology and Transfusion Medicine, Sigmund-Freud-Strasse 25, University Clinic Bonn, 53127 Bonn, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
111
|
Chen X, Tukachinsky H, Huang CH, Jao C, Chu YR, Tang HY, Mueller B, Schulman S, Rapoport TA, Salic A. Processing and turnover of the Hedgehog protein in the endoplasmic reticulum. ACTA ACUST UNITED AC 2011; 192:825-38. [PMID: 21357747 PMCID: PMC3051819 DOI: 10.1083/jcb.201008090] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Autocatalytic processing of the Hedgehog ligand from its precursor protein relies on protein disulfide isomerase and ER-associated degradation. The Hedgehog (Hh) signaling pathway has important functions during metazoan development. The Hh ligand is generated from a precursor by self-cleavage, which requires a free cysteine in the C-terminal part of the protein and results in the production of the cholesterol-modified ligand and a C-terminal fragment. In this paper, we demonstrate that these reactions occur in the endoplasmic reticulum (ER). The catalytic cysteine needs to form a disulfide bridge with a conserved cysteine, which is subsequently reduced by protein disulfide isomerase. Generation of the C-terminal fragment is followed by its ER-associated degradation (ERAD), providing the first example of an endogenous luminal ERAD substrate that is constitutively degraded. This process requires the ubiquitin ligase Hrd1, its partner Sel1, the cytosolic adenosine triphosphatase p97, and degradation by the proteasome. Processing-defective mutants of Hh are degraded by the same ERAD components. Thus, processing of the Hh precursor competes with its rapid degradation, explaining the impaired Hh signaling of processing-defective mutants, such as those causing human holoprosencephaly.
Collapse
Affiliation(s)
- Xin Chen
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
112
|
Chemical stress on protein disulfide isomerases and inhibition of their functions. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 290:121-66. [PMID: 21875564 DOI: 10.1016/b978-0-12-386037-8.00003-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein disulfide isomerase (PDI) is a folding assistant in the endoplasmic reticulum (ER) of eukaryotic cells. PDI has multiple roles, acting as a chaperone, a binding partner of other proteins, and a hormone reservoir as well as a disulfide isomerase in the formation of disulfide bonds. PDI only interacts covalently with the cysteines of its substrates, but also binds a variety of peptides/proteins and small chemical ligands such as thyroid hormone. Oxidative stress and nitrosative stress can cause damage to chaperones, protein misfolding, and neurodegenerative disease, by affecting the functional integrity of PDI. There are 20 putative PDI-family members in the ER of human cells, but their functional differentiation is far from complete. This review discusses recent advances in our understanding of the mammalian PDI family of enzymes and focuses on their functional properties and interaction with substrates and small chemical ligands.
Collapse
|
113
|
Watzka M, Geisen C, Bevans CG, Sittinger K, Spohn G, Rost S, Seifried E, Müller CR, Oldenburg J. Thirteen novel VKORC1 mutations associated with oral anticoagulant resistance: insights into improved patient diagnosis and treatment. J Thromb Haemost 2011; 9:109-18. [PMID: 20946155 DOI: 10.1111/j.1538-7836.2010.04095.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) is the molecular target of oral anticoagulants. Mutations in VKORC1 cause partial or total coumarin resistance. OBJECTIVES To identify new VKORC1 oral anticoagulant (OAC) resistance (OACR) mutations and compare the severity of patient phenotypes across different mutations and prescribed OAC drugs. PATIENTS/METHODS Six hundred and twenty-six individuals exhibiting partial or complete coumarin resistance were analyzed by VKORC1 gene sequencing and CYP2C9 haplotyping. RESULTS We identified 13 patients, each with a different, novel human VKORC1 heterozygous mutation associated with an OACR phenotype. These mutations result in amino acid substitutions: Ala26→Thr, His28→Gln, Asp36→Gly, Ser52→Trp, Ser56→Phe, Trp59→Leu, Trp59→Cys, Val66→Gly, Gly71→Ala, Asn77→Ser, Asn77→Tyr, Ile123→Asn, and Tyr139→His. Ten additional patients each had one of three previously reported VKORC1 mutations (Val29→Leu, Asp36→Tyr, and Val66→Met). Genotyping of frequent VKORC1 and CYP2C9 polymorphisms in these patients revealed a predominant association with combined non-VKORC1*2 and wild-type CYP2C9 haplotypes. Additionally, data for OAC dosage and the associated measured International Normalized Ratio (INR) demonstrate that OAC therapy is often discontinued by physicians, although stable therapeutic INR levels may be reached at higher OAC dosages. Bioinformatic analysis of VKORC1 homologous protein sequences indicated that most mutations cluster into protein sequence segments predicted to be localized in the lumenal loop or at the endoplasmic reticulum membrane-lumen interface. CONCLUSIONS OACR mutations of VKORC1 predispose afflicted patients to high OAC dosage requirements, for which stable, therapeutic INRs can sometimes be attained.
Collapse
Affiliation(s)
- M Watzka
- Institute of Experimental Hematology and Transfusion Medicine, University Clinic Bonn, Bonn, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
114
|
Hunting for Alternative Disulfide Bond Formation Pathways: Endoplasmic Reticulum Janitor Turns Professor and Teaches a Lesson. Mol Cell 2010; 40:685-6. [DOI: 10.1016/j.molcel.2010.11.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
115
|
Recycling of peroxiredoxin IV provides a novel pathway for disulphide formation in the endoplasmic reticulum. EMBO J 2010; 29:4185-97. [PMID: 21057456 PMCID: PMC3018787 DOI: 10.1038/emboj.2010.273] [Citation(s) in RCA: 191] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 10/15/2010] [Indexed: 12/16/2022] Open
Abstract
Disulphide formation in the endoplasmic reticulum (ER) is catalysed by members of the protein disulphide isomerase (PDI) family. These enzymes can be oxidized by the flavoprotein ER oxidoreductin 1 (Ero1), which couples disulphide formation with reduction of oxygen to form hydrogen peroxide (H(2)O(2)). The H(2)O(2) produced can be metabolized by ER-localized peroxiredoxin IV (PrxIV). Continuous catalytic activity of PrxIV depends on reduction of a disulphide within the active site to form a free thiol, which can then react with H(2)O(2). Here, we demonstrate that several members of the PDI family are able to directly reduce this PrxIV disulphide and in the process become oxidized. Furthermore, we show that altering cellular expression of these proteins within the ER influences the efficiency with which PrxIV can be recycled. The oxidation of PDI family members by PrxIV is a highly efficient process and demonstrates how oxidation by H(2)O(2) can be coupled to disulphide formation. Oxidation of PDI by PrxIV may therefore increase efficiency of disulphide formation by Ero1 and also allows disulphide formation via alternative sources of H(2)O(2).
Collapse
|