551
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Grillo C, D'Ambrosio C, Scaloni A, Maceroni M, Merluzzi S, Turano C, Altieri F. Cooperative activity of Ref-1/APE and ERp57 in reductive activation of transcription factors. Free Radic Biol Med 2006; 41:1113-23. [PMID: 16962936 DOI: 10.1016/j.freeradbiomed.2006.06.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 06/01/2006] [Accepted: 06/24/2006] [Indexed: 11/27/2022]
Abstract
ERp57, a protein disulfide isomerase localized mainly in the endoplasmic reticulum, has also been found in lesser amounts in the cytosol and nucleus, where its function is still not characterized. We report here that ERp57 displays affinity for Ref-1, a protein involved in DNA repair as well as in the reduction and activation of transcription factors. Immunoprecipitation experiments showed that Ref-1 and ERp57 also interact in vivo in at least three types of cultured human cells, namely HepG2, M14, and Raji. Oxidative stress increased the amount of nuclear Ref-1 associated with ERp57. Moreover, ERp57 reduced by the thioredoxin-reductase/thioredoxin system stimulated the binding of AP-1 to its consensus sequence on DNA, and HeLa cells stably transfected and overexpressing ERp57 were protected against hydrogen peroxide-induced cell killing. Accordingly, ERp57 appears to cooperate with Ref-1 in the regulation of gene expression mediated by redox-sensitive transcription factors and in the adaptive response of the cell to oxidative insult.
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Affiliation(s)
- Caterina Grillo
- Department of Biochemical Sciences A. Rossi Fanelli, University La Sapienza, P.le A. Moro 5, 00185 Rome, Italy
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552
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Camerer E, Trejo J. Cryptic messages: is noncoagulant tissue factor reserved for cell signaling? Proc Natl Acad Sci U S A 2006; 103:14259-60. [PMID: 16985001 PMCID: PMC1599949 DOI: 10.1073/pnas.0606888103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Eric Camerer
- *Cardiovascular Research Institute, University of California, San Francisco, CA 94143-2240; and
- To whom correspondence may be addressed. E-mail:
or
| | - JoAnn Trejo
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599-7365
- To whom correspondence may be addressed. E-mail:
or
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553
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Görlach A, Klappa P, Kietzmann T. The endoplasmic reticulum: folding, calcium homeostasis, signaling, and redox control. Antioxid Redox Signal 2006; 8:1391-418. [PMID: 16986999 DOI: 10.1089/ars.2006.8.1391] [Citation(s) in RCA: 500] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The endoplasmic reticulum (ER) plays a major role in regulating synthesis, folding, and orderly transport of proteins. It is also essentially involved in various cellular signaling processes, primarily by its function as a dynamic Ca(2+) store. Compared to the cytosol, oxidizing conditions are found in the ER that allow oxidation of cysteine residues in nascent polypeptide chains to form intramolecular disulfide bonds. However, compounds and enzymes such as PDI that catalyze disulfide bonds become reduced and have to be reoxidized for further catalytic cycles. A number of enzymes, among them products of the ERO1 gene, appear to provide oxidizing equivalents, and oxygen appears to be the final oxidant in aerobic living organisms. Thus, protein oxidation in the ER is connected with generation of reactive oxygen species (ROS). Changes in the redox state and the presence of ROS also affect the Ca(2+) homeostasis by modulating the functionality of ER-based channels and buffering chaperones. In addition, a close relationship exists between oxidative stress and ER stress, which both may activate signaling events leading to a rebalance of folding capacity and folding demand or to cell death. Thus, redox homeostasis appears to be a prerequisite for proper functioning of the ER.
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Affiliation(s)
- Agnes Görlach
- Experimental Pediatric Cardiology, Department of Pediatric Cardiology and Congenital Heart Disease, German Heart Center Munich at the Technical University Munich, Munich, Germany
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554
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Kim SJ, Choi YS, Kim HG, Park EH, Lim CJ. Cloning, characterization and regulation of a protein disulfide isomerase from the fission yeast Schizosaccharomyces pombe. Mol Biol Rep 2006; 33:187-96. [PMID: 16850188 DOI: 10.1007/s11033-006-0012-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 03/08/2006] [Indexed: 10/24/2022]
Abstract
To elucidate the physiological roles and regulation of a protein disulfide isomerase (PDI) from the fission yeast Schizosaccharomyces pombe, the full-length PDI gene was ligated into the shuttle vector pRS316, resulting in pPDI10. The determined DNA sequence carries 1,636 bp and encodes the putative 359 amino acid sequence of PDI with a molecular mass of 39,490 Da. In the amino acid sequence, the S. pombe PDI appears to be very homologous to A. thaliana PDI. The S. pombe cells harboring pPDI10 showed increased PDI activity and accelerated growth, suggesting that the cloned PDI gene is functioning and involved in the yeast growth. The 460 bp upstream region of the PDI gene was fused into promoterless beta-galactosidase gene of the shuttle vector YEp367R to generate pYUPDI10. The synthesis of beta-galactosidase from the PDI-lacZ fusion gene was enhanced by oxidative stress, such as superoxide anion and hydrogen peroxide. It was also induced by some non-fermentable and fermentable carbon sources. Nitrogen starvation was able to enhance the synthesis of beta-galactosidase from the PDI-lacZ fusion gene. The enhancement by oxidative stress and fermentable carbon sources did not depend on the presence of Pap1. The PDI mRNA levels were increased in both Pap1-positive and Pap1-negative cells treated with glycerol. Taken together, the S. pombe PDI gene is involved in cellular growth and response to nutritional and oxidative stress.
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Affiliation(s)
- Su-Jung Kim
- Division of Life Sciences, College of Natural Sciences, Kangwon National University, 192-1 Hyoja-2-dong, Chuncheon 200-701, Korea
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555
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Abstract
Disulfide bonds are required for the stability and function of a large number of proteins. Recently, the results from genome analysis have suggested an important role for disulfide bonds concerning the structural stabilization of intracellular proteins from hyperthermophilic Archaea and Bacteria, contrary to the conventional view that structural disulfide bonds are rare in proteins from Archaea. A specific protein, known as protein disulfide oxidoreductase (PDO) is recognized as a potential key player in intracellular disulfide-shuffling in hyperthermophiles. The structure of this protein shows a combination of two thioredoxin-related units with low sequence identity which together, in tandem-like manner, form a closed protein domain. Each of these units contains a distinct CXXC active site motif. Due to their estimated conformational energies, both sites are likely to have different redox properties. The observed structural and functional characteristics suggest a relation to eukaryotic protein disulfide isomerase. Functional studies have revealed that both the archaeal and bacterial forms of this protein show oxidative and reductive activity and are able to isomerize protein disulfides. The physiological substrates and reduction systems, however, are to date unknown. The variety of active site disulfides found in PDOs from hyperthermophiles is puzzling. Nevertheless, the catalytic function of any PDO is expected to be correlated with the redox properties of its active site disulfides CXXC and with the distinct nature of its redox environment. The residues around the two active sites form two grooves on the protein surface. In analogy to a similar groove in thioredoxin, both grooves are suggested to constitute the substrate binding sites of PDO. The direct neighbourhood of the grooves and the different redox properties of both sites may favour sequential reactions in protein disulfide shuffling, like reduction followed by oxidation. A model for peptide binding by PDO is proposed to be derived from the analysis of crystal packing contacts mimicking substrate binding interactions. It is assumed, that PDO enzymes in hyperthermophilic Archaea and Bacteria may be part of a complex system involved in the maintenance of protein disulfide bonds. The regulation of disulfide bond formation may be dependent on a distinct interplay of thermodynamic and kinetic effects, including functional asymmetry and substrate-mediated protection of the active sites, in analogy to the situation in protein disulfide isomerase. Numerous questions related to the function of PDO enzymes in hyperthermophiles remain unanswered to date, but can probably successfully be studied by a number of approaches, such as first-line genetic and in vivo studies.
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Affiliation(s)
- Rudolf Ladenstein
- Karolinska Institutet NOVUM, Center of Structural Biochemistry, Huddinge, Sweden.
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556
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Su HP, Lin DYW, Garboczi DN. The structure of G4, the poxvirus disulfide oxidoreductase essential for virus maturation and infectivity. J Virol 2006; 80:7706-13. [PMID: 16840349 PMCID: PMC1563705 DOI: 10.1128/jvi.00521-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The possibility of the release of smallpox virus into a predominantly nonimmunized population highlights the importance of understanding poxvirus biology. Poxviruses encode a conserved pathway that is required to oxidize disulfide bonds in nascent viral proteins that fold in the reducing environment of the eukaryotic host cytoplasm. We present the structure of the last enzyme of the vaccinia virus pathway, G4, which is almost identical in smallpox virus. G4 catalyzes the formation of disulfide bonds in proteins that are critical for virus maturation and host cell infection. G4 contains a thioredoxin fold and a Cys-X-X-Cys active site. In solution, G4 monomers and dimers are observed. In the crystal, G4 is found as a dimer that buries 4,500 A(2) in the interface and occludes the active site, which could protect the reactive disulfide from reduction in the cytoplasm. The structure serves as a model for drug design targeting viral disulfide bond formation.
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Affiliation(s)
- Hua-Poo Su
- Structural Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD 20852, USA
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557
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Kozlov G, Maattanen P, Schrag JD, Pollock S, Cygler M, Nagar B, Thomas DY, Gehring K. Crystal Structure of the bb′ Domains of the Protein Disulfide Isomerase ERp57. Structure 2006; 14:1331-9. [PMID: 16905107 DOI: 10.1016/j.str.2006.06.019] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 06/10/2006] [Accepted: 06/13/2006] [Indexed: 11/23/2022]
Abstract
The synthesis of proteins in the endoplasmic reticulum (ER) is limited by the rate of correct disulfide bond formation. This process is carried out by protein disulfide isomerases, a family of ER proteins which includes general enzymes such as PDI that recognize unfolded proteins and others that are selective for specific proteins or classes. Using small-angle X-ray scattering and X-ray crystallography, we report the structure of a selective isomerase, ERp57, and its interactions with the lectin chaperone calnexin. Using isothermal titration calorimetry and NMR spectroscopy, we show that the b' domain of ERp57 binds calnexin with micromolar affinity through a conserved patch of basic residues. Disruption of this binding site by mutagenesis abrogates folding of RNase B in an in vitro assay. The relative positions of the ERp57 catalytic sites and calnexin binding site suggest that activation by calnexin is due to substrate recruitment rather than a direct stimulation of ERp57 oxidoreductase activity.
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Affiliation(s)
- Guennadi Kozlov
- Biochemistry Department, McGill University, 3655 Promenade Sir William Osler, Montréal, Québec H3G 1Y6, Canada
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558
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559
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Gruber CW, Cemazar M, Heras B, Martin JL, Craik DJ. Protein disulfide isomerase: the structure of oxidative folding. Trends Biochem Sci 2006; 31:455-64. [PMID: 16815710 DOI: 10.1016/j.tibs.2006.06.001] [Citation(s) in RCA: 248] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 05/11/2006] [Accepted: 06/12/2006] [Indexed: 01/09/2023]
Abstract
Cellular functions hinge on the ability of proteins to adopt their correct folds, and misfolded proteins can lead to disease. Here, we focus on the proteins that catalyze disulfide bond formation, a step in the oxidative folding pathway that takes place in specialized cellular compartments. In the endoplasmic reticulum of eukaryotes, disulfide formation is catalyzed by protein disulfide isomerase (PDI); by contrast, prokaryotes produce a family of disulfide bond (Dsb) proteins, which together achieve an equivalent outcome in the bacterial periplasm. The recent crystal structure of yeast PDI has increased our understanding of the function and mechanism of PDI. Comparison of the structure of yeast PDI with those of bacterial DsbC and DsbG reveals some similarities but also striking differences that suggest directions for future research aimed at unraveling the catalytic mechanism of disulfide bond formation in the cell.
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Affiliation(s)
- Christian W Gruber
- Institute for Molecular Bioscience and Australian Research Council Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, QLD 4072, Australia
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560
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Benhar M, Forrester MT, Stamler JS. Nitrosative stress in the ER: a new role for S-nitrosylation in neurodegenerative diseases. ACS Chem Biol 2006; 1:355-8. [PMID: 17163772 DOI: 10.1021/cb600244c] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
S-Nitrosylation, the covalent addition of a nitrogen monoxide group to a cysteine thiol, has been shown to modify the function of a broad spectrum of mammalian, plant, and microbial proteins and thereby to convey the ubiquitous influence of nitric oxide on cellular signal transduction and host defense. Accumulating evidence indicates that dysregulated, diminished, or excessive S-nitrosylation may be implicated in a wide range of pathophysiological conditions. A recent study establishes a functional relationship between inhibitory S-nitrosylation of the redox enzyme protein disulfide isomerase (PDI), defects in regulation of protein folding within the endoplasmic reticulum (ER), and neurodegeneration. Further, an examination of human brains afflicted with Parkinson's or Alzheimer's disease supports a causal role for the S-nitrosylation of PDI and consequent ER stress in these prevalent neurodegenerative disorders.
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Affiliation(s)
- Moran Benhar
- Department of Biochemistry, Duke University Medical Center, Box 2612, Durham, North Carolina, USA
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561
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Chambery A, Farina A, Di Maro A, Rossi M, Abbondanza C, Moncharmont B, Malorni L, Cacace G, Pocsfalvi G, Malorni A, Parente A. Proteomic analysis of MCF-7 cell lines expressing the zinc-finger or the proline-rich domain of retinoblastoma-interacting-zinc-finger protein. J Proteome Res 2006; 5:1176-85. [PMID: 16674107 DOI: 10.1021/pr0504743] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To identify a growth-promoting activity related to retinoblastoma-interacting-zinc-finger (RIZ) protein, differential protein expression of MCF-7 cell lines expressing the zinc-finger or the proline-rich domain of RIZ protein was analyzed by a robust bottom-up mass-spectrometry proteomic approach. Spots corresponding to qualitative and quantitative differences in protein expression have been selected and identified. Some of these proteins have been previously reported as being associated with different types of carcinomas or involved in cell proliferation and differentiation. Knowledge of specific differentially expressed proteins by MCF-7-derived cell lines expressing RIZ different domains will provide the basis for identifying a growth-promoting activity related to RIZ gene products.
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Affiliation(s)
- Angela Chambery
- Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, I-81100 Caserta, Italy
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562
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Chakravarthi S, Jessop CE, Bulleid NJ. The role of glutathione in disulphide bond formation and endoplasmic-reticulum-generated oxidative stress. EMBO Rep 2006; 7:271-5. [PMID: 16607396 PMCID: PMC1456887 DOI: 10.1038/sj.embor.7400645] [Citation(s) in RCA: 312] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 01/13/2006] [Indexed: 11/08/2022] Open
Abstract
Glutathione is a ubiquitous molecule found in all parts of the cell where it fulfils a range of functions from detoxification to protection from oxidative damage. It provides the main redox buffer for cells and as such has been implicated in the formation of native disulphide bonds. However, the discovery of the enzyme Ero1 has called into question the exact role of glutathione in this process. In this review, we discuss the arguments for and against a role for glutathione in facilitating disulphide-bond formation and consider its role in protecting the cell from endoplasmic-reticulum-generated oxidative stress.
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Affiliation(s)
- Seema Chakravarthi
- The Faculty of Life Sciences, University of Manchester, The Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
- These authors contributed equally to this work
| | - Catherine E Jessop
- The Faculty of Life Sciences, University of Manchester, The Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
- These authors contributed equally to this work
| | - Neil J Bulleid
- The Faculty of Life Sciences, University of Manchester, The Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
- Tel: +44 161 275 5103; Fax: +44 161 275 5082; E-mail:
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563
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Chromy LR, Oltman A, Estes PA, Garcea RL. Chaperone-mediated in vitro disassembly of polyoma- and papillomaviruses. J Virol 2006; 80:5086-91. [PMID: 16641302 PMCID: PMC1472060 DOI: 10.1128/jvi.80.10.5086-5091.2006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hsp70 chaperones play a role in polyoma- and papillomavirus assembly, as evidenced by their interaction in vivo with polyomavirus capsid proteins at late times after virus infection and by their ability to assemble viral capsomeres into capsids in vitro. We studied whether Hsp70 chaperones might also participate in the uncoating reaction. In vivo, Hsp70 co-immunoprecipitated with polyomavirus virion VP1 at 3 h after infection of mouse cells. In vitro, prokaryotic and eukaryotic Hsp70 chaperones efficiently disassembled polyoma- and papillomavirus-like particles and virions in energy-dependent reactions. These observations support a role for cell chaperones in the disassembly of these viruses.
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Affiliation(s)
- Laura R Chromy
- University of Colorado Health Sciences Center, Aurora, CO 80045, USA
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564
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Abstract
The ClC family of chloride channels and transporters includes several members in which mutations have been associated with human disease. An understanding of the structure-function relationships of these proteins is essential for defining the molecular mechanisms underlying pathogenesis. To date, the X-ray crystal structures of prokaryotic ClC transporter proteins have been used to model the membrane domains of eukaryotic ClC channel-forming proteins. Clearly, the fidelity of these models must be evaluated empirically. In the present study, biochemical tools were used to define the membrane domain boundaries of the eukaryotic protein, ClC-2, a chloride channel mutated in cases of idiopathic epilepsy. The membrane domain boundaries of purified ClC-2 and accessible cysteine residues were determined after its functional reconstitution into proteoliposomes, labelling using a thiol reagent and proteolytic digestion. Subsequently, the lipid-embedded and soluble fragments generated by trypsin-mediated proteolysis were studied by MS and coverage of approx. 71% of the full-length protein was determined. Analysis of these results revealed that the membrane-delimited boundaries of the N- and C-termini of ClC-2 and the position of several extramembrane loops determined by these methods are largely similar to those predicted on the basis of the prokaryotic protein [ecClC (Escherichia coli ClC)] structures. These studies provide direct biochemical evidence supporting the relevance of the prokaryotic ClC protein structures towards understanding the structure of mammalian ClC channel-forming proteins.
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Affiliation(s)
- Mohabir Ramjeesingh
- Programme of Structural Biology and Biochemistry, Research Institute of the Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8
| | - Canhui Li
- Programme of Structural Biology and Biochemistry, Research Institute of the Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8
| | - Yi-Min She
- Programme of Structural Biology and Biochemistry, Research Institute of the Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8
| | - Christine E. Bear
- Programme of Structural Biology and Biochemistry, Research Institute of the Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8
- To whom correspondence should be addressed (email )
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565
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Arolas JL, Bronsoms S, Ventura S, Aviles FX, Calvete JJ. Characterizing the tick carboxypeptidase inhibitor: molecular basis for its two-domain nature. J Biol Chem 2006; 281:22906-16. [PMID: 16760476 DOI: 10.1074/jbc.m602301200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tick carboxypeptidase inhibitor (TCI) is a small, disulfide-rich protein that selectively inhibits metallocarboxypeptidases and strongly accelerates the fibrinolysis of blood clots. TCI consists of two domains that are structurally very similar, each containing three disulfide bonds arranged in an almost identical fashion. The oxidative folding and reductive unfolding pathways of TCI and its separated domains have been characterized by kinetic and structural analysis of the acid-trapped folding intermediates. TCI folding proceeds through a sequential formation of 1-, 2-, 3-, 4-, 5-, and 6-disulfide species to reach the native form. Folding intermediates of TCI comprise two predominant 3-disulfide species (named IIIa and IIIb) and a major 6-disulfide scrambled isomer (Xa) that consecutively accumulate along the reaction and are strongly prevented by the presence of protein disulfide isomerase. This study demonstrates that IIIa and IIIb are 3-disulfide species containing the native disulfide pairings of the N- and C-terminal domains of TCI, respectively, and explains why the two domains of TCI fold sequentially and independently. Also, we show that the reductive unfolding of TCI undergoes two main independent unfolding events through the formation of IIIa and IIIb intermediates. Together, the comparison of the folding, stability, and inhibitory activity of TCI with those of the isolated domains reveals the reasons behind the two-domain nature of this protein: both domains contribute to the specificity and high affinity of its double-headed binding to carboxypeptidases. The results obtained herein provide valuable information for the design of more potent and selective TCI molecules.
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Affiliation(s)
- Joan L Arolas
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona
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566
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Ellerman DA, Myles DG, Primakoff P. A Role for Sperm Surface Protein Disulfide Isomerase Activity in Gamete Fusion: Evidence for the Participation of ERp57. Dev Cell 2006; 10:831-7. [PMID: 16740484 DOI: 10.1016/j.devcel.2006.03.011] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 03/02/2006] [Accepted: 03/28/2006] [Indexed: 11/16/2022]
Abstract
In mammals, sperm-egg interaction is based on molecular events either unique to gametes or also present in somatic cells. In gamete fusion, it is unknown which features are gamete specific and which are shared with other systems. Conformational changes mediated by thiol-disulfide exchange are involved in the activation of some virus membrane fusion proteins. Here we asked whether that mechanism is also operative in sperm-egg fusion. Different inhibitors of protein disulfide isomerase (PDI) activity were able to inhibit sperm-egg fusion in vitro. While pretreatment of oocytes had no effect, pretreatment of sperm reduced their fusion ability. Some members of the PDI family were detected on the sperm head, and use of specific antibodies and substrates suggested that the oxidoreductase ERp57 has a role in gamete fusion. The results support the idea that thiol-disulfide exchange is a mechanism that may act in gamete fusion to produce conformational changes in fusion-active proteins.
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Affiliation(s)
- Diego A Ellerman
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Davis, California 95616, USA.
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567
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Walker MJ, Rylett CM, Keen JN, Audsley N, Sajid M, Shirras AD, Isaac RE. Proteomic identification of Drosophila melanogaster male accessory gland proteins, including a pro-cathepsin and a soluble gamma-glutamyl transpeptidase. Proteome Sci 2006; 4:9. [PMID: 16670001 PMCID: PMC1462989 DOI: 10.1186/1477-5956-4-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 05/02/2006] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND In Drosophila melanogaster, the male seminal fluid contains proteins that are important for reproductive success. Many of these proteins are synthesised by the male accessory glands and are secreted into the accessory gland lumen, where they are stored until required. Previous studies on the identification of Drosophila accessory gland products have largely focused on characterisation of male-specific accessory gland cDNAs from D. melanogaster and, more recently, Drosophila simulans. In the present study, we have used a proteomics approach without any sex bias to identify proteins in D. melanogaster accessory gland secretions. RESULTS Thirteen secreted accessory gland proteins, including seven new accessory gland proteins, were identified by 2D-gel electrophoresis combined with mass spectrometry of tryptic fragments. They included protein-folding and stress-response proteins, a hormone, a lipase, a serpin, a cysteine-rich protein and two peptidases, a pro-enzyme form of a cathepsin K-like cysteine peptidase and a gamma-glutamyl transpeptidase. Enzymatic studies established that accessory gland secretions contain a cysteine peptidase zymogen that can be activated at low pH. This peptidase may have a role in the processing of female and other male-derived proteins, but is unlikely to be involved in the processing of the sex peptide. gamma-Glutamyl transpeptidases are type II integral membrane proteins; however, the identified AG gamma-glutamyl transpeptidase (GGT-1) is unusual in that it is predicted to be a soluble secreted protein, a prediction that is supported by biochemical evidence. GGT-1 is possibly involved in maintaining a protective redox environment for sperm. The strong gamma-glutamyl transpeptidase activity found in the secretions provides an explanation for the observation that glutamic acid is the most abundant free amino acid in accessory gland secretions of D. melanogaster. CONCLUSION We have applied biochemical approaches, not used previously, to characterise prominent D. melanogaster accessory gland products. Of the thirteen accessory gland secreted proteins reported in this study, six were represented in a D. simulans male accessory gland EST library that was biased for male-specific genes. Therefore, the present study has identified seven new secreted accessory gland proteins, including GGT-1, which was not recognised previously as a secreted accessory gland product.
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Affiliation(s)
- Michael J Walker
- Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Caroline M Rylett
- Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jeff N Keen
- Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Neil Audsley
- Environmental Biology Group, Central Science Laboratory, Sand Hutton, York YO41 1LZ, UK
| | - Mohammed Sajid
- Sandler Center for Basic Research in Parasitic Diseases, Department of Pathology, University of California San Francisco, HSW501 San Francisco, CA 94143, USA
| | - Alan D Shirras
- Department of Biological Sciences, University of Lancaster, LA1 4YQ, UK
| | - R Elwyn Isaac
- Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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568
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Zhang Y, Baig E, Williams DB. Functions of ERp57 in the Folding and Assembly of Major Histocompatibility Complex Class I Molecules. J Biol Chem 2006; 281:14622-31. [PMID: 16567808 DOI: 10.1074/jbc.m512073200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ERp57 is a thiol oxidoreductase of the endoplasmic reticulum that appears to be recruited to substrates indirectly through its association with the molecular chaperones calnexin and calreticulin. However, its functions in living cells have been difficult to demonstrate. During the biogenesis of class I histocompatibility molecules, ERp57 has been detected in association with free class I heavy chains and, at a later stage, with a large complex termed the peptide loading complex. This implicates ERp57 in heavy chain disulfide formation, isomerization, or reduction as well as in the loading of peptides onto class I molecules. In this study, we show that ERp57 does indeed participate in oxidative folding of the heavy chain. Depletion of ERp57 by RNA interference delayed heavy chain disulfide bond formation, slowed folding of the heavy chain alpha(3) domain, and caused slight delays in the transport of class I molecules from the endoplasmic reticulum to the Golgi apparatus. In contrast, heavy chain-beta(2)-microglobulin association kinetics were normal, suggesting that the interaction between heavy chain and beta(2) -microglobulin does not depend on an oxidized alpha(3) domain. Likewise, the peptide loading complex assembled properly, and peptide loading appeared normal upon depletion of ERp57. These studies demonstrate that ERp57 is involved in disulfide formation in vivo but do not support a role for ERp57 in peptide loading of class I molecules. Interestingly, depletion of another thiol oxidoreductase, ERp72, had no detectable effect on class I biogenesis, consistent with a specialized role for ERp57 in this process.
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Affiliation(s)
- Yinan Zhang
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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569
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Abstract
Two pathways for the formation of biosynthetic protein disulfide bonds have been characterized in the endoplasmic reticulum (ER) of eukaryotes. In the major pathway, the membrane-associated flavoprotein Ero1 generates disulfide bonds for transfer to protein disulfide isomerase (PDI), which is responsible for directly introducing disulfide bonds into secretory proteins. In a minor fungal-specific protein oxidation pathway, the membrane-associated flavoprotein Erv2 can catalyze disulfide bond formation via the transfer of oxidizing equivalents to PDI. Genomic sequencing has revealed an abundance of enzymes sharing homology with Ero1, Erv2, or PDI. Herein the authors discuss the functional, mechanistic, and potential structural similarities between these homologs and the core enzymes of the characterized ER oxidation pathways. In addition they speculate about the possible differences between these enzymes that may explain why the cell contains multiple proteins dedicated to a single process. Finally, the eukaryotic ER protein oxidation and reduction pathways are compared to the corresponding prokaryotic periplasmic pathways, to highlight the functional, mechanistic, and structural similarities that exist between the pathways in these two kingdoms despite very low primary sequence homology between the protein and small molecule components.
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Affiliation(s)
- Carolyn S Sevier
- Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139, USA
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570
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Drew JE, Padidar S, Horgan G, Duthie GG, Russell WR, Reid M, Duncan G, Rucklidge GJ. Salicylate modulates oxidative stress in the rat colon: a proteomic approach. Biochem Pharmacol 2006; 72:204-16. [PMID: 16730665 DOI: 10.1016/j.bcp.2006.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 04/06/2006] [Indexed: 02/08/2023]
Abstract
The dietary phenolic compound, salicylic acid, decreases oxidative stress and pro-inflammatory and potentially neo-plastic prostaglandins with a concomitant increase in glutathione peroxidase activity. Salicylic acid, a dietary plant-based phenolic compound and also the main metabolite of aspirin, may contribute to the colon protective effects of plant-based diets. Oxidative stress is a characteristic of pre-cancerous and cancerous colon and inflammatory bowel diseases (IBD) that increase colon cancer risk. The mechanism(s) whereby salicylic acid modulates potentially pro-cancerous activity associated with oxidative stress is further investigated here using a proteomic approach. A rat model of oxidative stress was supplemented with salicylic acid (1 mg/kg diet, mean plasma levels 310+/-32 micromol/l). Soluble colon protein extracts were subjected to 2D PAGE. Salicylic acid modulated proteins, identified using MALDI-TOF and LC/MS/MS, are involved in protein folding, transport, redox, energy metabolism and cytoskeletal regulation. A partial least squares (PLS) analysis approach was used to assist biological interpretation of the altered protein profiles via their associations between previously published biochemical measurements of oxidative stress, prostaglandin levels and increased glutathione peroxidase activity. Early detection of altered homeostasis in colon may assist in identifying pre-pathological features preceding colon tumorigenesis and contribute to an understanding of epidemiological evidence supporting a protective effect of plant-based diets.
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Affiliation(s)
- Janice E Drew
- Gut Health Division, Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen, AB21 9SB Scotland, UK.
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571
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Rodríguez I, Redrejo-Rodríguez M, Rodríguez JM, Alejo A, Salas J, Salas ML. African swine fever virus pB119L protein is a flavin adenine dinucleotide-linked sulfhydryl oxidase. J Virol 2006; 80:3157-66. [PMID: 16537584 PMCID: PMC1440384 DOI: 10.1128/jvi.80.7.3157-3166.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Protein pB119L of African swine fever virus belongs to the Erv1p/Alrp family of sulfhydryl oxidases and has been described as a late nonstructural protein required for correct virus assembly. To further our knowledge of the function of protein pB119L during the virus life cycle, we have investigated whether this protein possesses sulfhydryl oxidase activity, using a purified recombinant protein. We show that the purified protein contains bound flavin adenine dinucleotide and is capable of catalyzing the formation of disulfide bonds both in a protein substrate and in the small molecule dithiothreitol, the catalytic activity being comparable to that of the Erv1p protein. Furthermore, protein pB119L contains the cysteines of its active-site motif CXXC, predominantly in an oxidized state, and forms noncovalently bound dimers in infected cells. We also show in coimmunoprecipitation experiments that protein pB119L interacts with the viral protein pA151R, which contains a CXXC motif similar to that present in thioredoxins. Protein pA151R, in turn, was found to interact with the viral structural protein pE248R, which contains disulfide bridges and belongs to a class of myristoylated proteins related to vaccinia virus L1R, one of the substrates of the redox pathway encoded by this virus. These results suggest the existence in African swine fever virus of a system for the formation of disulfide bonds constituted at least by proteins pB119L and pA151R and identify protein pE248R as a possible final substrate of this pathway.
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Affiliation(s)
- Irene Rodríguez
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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572
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Arolas JL, Aviles FX, Chang JY, Ventura S. Folding of small disulfide-rich proteins: clarifying the puzzle. Trends Biochem Sci 2006; 31:292-301. [PMID: 16600598 DOI: 10.1016/j.tibs.2006.03.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 02/20/2006] [Accepted: 03/22/2006] [Indexed: 11/21/2022]
Abstract
The process by which small proteins fold to their native conformations has been intensively studied over the past few decades. The particular chemistry of disulfide-bond formation has facilitated the characterization of the oxidative folding of numerous small, disulfide-rich proteins with results that illustrate a high level of diversity in folding mechanisms, differing in the heterogeneity and native disulfide-bond content of their intermediates. Information from folding studies of these proteins, together with the recent structural determinations of predominant intermediates, has provided new molecular insights into oxidative folding and clarifies the major rules that govern it.
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Affiliation(s)
- Joan L Arolas
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona; 08193 Bellaterra, Barcelona, Spain
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573
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Tian G, Xiang S, Noiva R, Lennarz WJ, Schindelin H. The crystal structure of yeast protein disulfide isomerase suggests cooperativity between its active sites. Cell 2006; 124:61-73. [PMID: 16413482 DOI: 10.1016/j.cell.2005.10.044] [Citation(s) in RCA: 292] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 08/24/2005] [Accepted: 10/11/2005] [Indexed: 01/01/2023]
Abstract
Protein disulfide isomerase plays a key role in catalyzing the folding of secretory proteins. It features two catalytically inactive thioredoxin domains inserted between two catalytically active thioredoxin domains and an acidic C-terminal tail. The crystal structure of yeast PDI reveals that the four thioredoxin domains are arranged in the shape of a twisted "U" with the active sites facing each other across the long sides of the "U." The inside surface of the "U" is enriched in hydrophobic residues, thereby facilitating interactions with misfolded proteins. The domain arrangement, active site location, and surface features strikingly resemble the Escherichia coli DsbC and DsbG protein disulfide isomerases. Biochemical studies demonstrate that all domains of PDI, including the C-terminal tail, are required for full catalytic activity. The structure defines a framework for rationalizing the differences between the two active sites and their respective roles in catalyzing the formation and rearrangement of disulfide bonds.
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Affiliation(s)
- Geng Tian
- Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, NY 11794, USA
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574
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Otsu M, Bertoli G, Fagioli C, Guerini-Rocco E, Nerini-Molteni S, Ruffato E, Sitia R. Dynamic retention of Ero1alpha and Ero1beta in the endoplasmic reticulum by interactions with PDI and ERp44. Antioxid Redox Signal 2006; 8:274-82. [PMID: 16677073 DOI: 10.1089/ars.2006.8.274] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Disulfide bonds are formed in the endoplasmic reticulum (ER) by sequential interchange reactions: Ero1alpha and Ero1beta transfer oxidative equivalents to protein disulfide isomerase (PDI), which in turn oxidizes cargo proteins. Neither Ero1alpha nor Ero1beta contains known ER localization motif(s), raising the question of how they are retained in this organelle. Here the authors show that, unlike endogenous molecules, overexpressed Ero1alpha and Ero1beta are secreted by HeLa transfectants, suggesting saturation of their normal retention mechanism(s). Co-expression of either PDI or ERp44 prevents Ero1 secretion in a KDEL/RDEL dependent way. Covalent interactions between ERp44 and Ero1 are essential for retention. In contrast, a mutant PDI lacking the four cysteines in the two active sites still inhibits secretion, albeit less efficiently. PDI and ERp44 compete for Ero1 binding. PDI also prevents Ero1 aggregation and dimerization, thus chaperoning its own oxidase. This dynamic retention mechanism of Ero1 may be important for fine-tuning the regulation of ER redox homeostasis and quality control.
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Affiliation(s)
- Mieko Otsu
- DiBiT San Raffaele Scientific Institute, and Università Vita-Salute San Raffaele, Milano, Italy
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575
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Alanen HI, Salo KEH, Pirneskoski A, Ruddock LW. pH dependence of the peptide thiol-disulfide oxidase activity of six members of the human protein disulfide isomerase family. Antioxid Redox Signal 2006; 8:283-91. [PMID: 16677074 DOI: 10.1089/ars.2006.8.283] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Protein folding in the endoplasmic reticulum is often associated with the formation of native disulfide bonds, a process which in vivo is one of the rate limiting steps of protein folding and which is facilitated by the enzyme protein disulfide isomerase (PDI). Higher eukaryotes have multiple members of the PDI family, for example, seventeen human PDIs have been reported to date. With multiple members of the same family being present, even within the same cell, the question arises as to what differential functions are they performing? To date there has been no systematic evaluation of the enzymological properties of the different members of the PDI-family. To address the question of whether different PDI family members have differing thioldisulfide chemistry, we have recombinantly expressed and purified six members of the family, PDI, PDIp, ERp57, ERp72, P5, and PDIr from a single organism, human. An examination of the pH-dependence and nature of the rate limiting step for the peptide thiol-disulfide oxidase activity of these enzymes reveals that, with the exception of PDIr, they are all remarkably similar. In the light of this data potential differential functions for these enzymes are discussed.
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Affiliation(s)
- H I Alanen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Oulu, Finland
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576
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Soldà T, Garbi N, Hämmerling GJ, Molinari M. Consequences of ERp57 Deletion on Oxidative Folding of Obligate and Facultative Clients of the Calnexin Cycle. J Biol Chem 2006; 281:6219-26. [PMID: 16407314 DOI: 10.1074/jbc.m513595200] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Members of the protein-disulfide isomerase superfamily catalyze the formation of intra- and intermolecular disulfide bonds, a rate-limiting step of protein folding in the endoplasmic reticulum (ER). Here we compared maturation of one obligate and two facultative calnexin substrates in cells with and without ERp57, the calnexin-associated, glycoprotein-specific oxidoreductase. ERp57 deletion did not prevent the formation of disulfide bonds during co-translational translocation of nascent glycopolypeptides in the ER. It affected, however, the post-translational phases of oxidative influenza virus hemagglutinin (HA) folding, resulting in significant loss of folding efficiency for this obligate calnexin substrate. Without ERp57, HA also showed reduced capacity to recover from an artificially induced aberrant conformation, thus revealing a crucial role of ERp57 during post-translational reshuffling to the native set of HA disulfides. ERp57 deletion did not affect maturation of the model facultative calnexin substrates E1 and p62 (and of most cellular proteins, as shown by lack of induction of ER stress). ERp72 was identified as one of the ER-resident oxidoreductases associating with the orphan ERp57 substrates to maintain their folding competence.
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Affiliation(s)
- Tatiana Soldà
- Institute for Research in Biomedicine, CH-6500 Bellinzona, Switzerland
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577
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Wang X, Thomas B, Sachdeva R, Arterburn L, Frye L, Hatcher PG, Cornwell DG, Ma J. Mechanism of arylating quinone toxicity involving Michael adduct formation and induction of endoplasmic reticulum stress. Proc Natl Acad Sci U S A 2006; 103:3604-9. [PMID: 16505371 PMCID: PMC1450130 DOI: 10.1073/pnas.0510962103] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quinones permeate our biotic environment, contributing to both homeostasis and cytotoxicity. All quinones generate reactive oxygen species through redox cycling, while partially substituted quinones also undergo arylation (Michael adduct formation) yielding covalent bonds with nucleophiles such as cysteinyl thiols. In contrast to reactive oxygen species, the role of arylation in quinone cytotoxicity is not well understood. We found that the arylating quinones, including unsubstituted 1,4-benzoquinone (1,4-BzQ) and partially substituted vitamin E congener gamma-tocopherol quinone (gamma-TQ), were cytotoxic, with gamma-TQ > 1,4-BzQ, whereas the fully substituted nonarylating vitamin E congener alpha-tocopherol quinone was not. In vitro, both arylating quinones formed Michael adducts with the thiol nucleophile N-acetylcysteine (NAC) at rates where 1,4-BzQ > gamma-TQ. In cultured cells, concurrent addition of NAC eliminated 1,4-BzQ caused toxicity, but preincubation was required for the same NAC detoxification effect on gamma-TQ. These data clearly established the role of arylation in quinone toxicity and revealed that arylating quinone structure affects cytotoxicity by governing detoxification through the rate of adduct formation. Furthermore, arylating quinones induced endoplasmic reticulum (ER) stress by activating the pancreatic ER kinase (PERK) signaling pathway including elF2alpha, ATF4, and C/EBP homologous protein (CHOP). Detoxification by NAC greatly attenuates CHOP induction in arylating quinone-treated cells, suggesting that ER stress is a cellular mechanism for arylating quinone cytotoxicity.
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Affiliation(s)
- Xinhe Wang
- Departments of *Molecular and Cellular Biochemistry and
| | - Beena Thomas
- Chemistry, Ohio State University, Columbus, OH 43210
| | | | | | - Lucy Frye
- Departments of *Molecular and Cellular Biochemistry and
| | | | - David G. Cornwell
- Departments of *Molecular and Cellular Biochemistry and
- To whom correspondence may be addressed at:
Department of Molecular and Cellular Biochemistry, Ohio State University, 1645 Neil Avenue, Columbus, OH 43210. E-mail:
or
| | - Jiyan Ma
- Departments of *Molecular and Cellular Biochemistry and
- To whom correspondence may be addressed at:
Department of Molecular and Cellular Biochemistry, Ohio State University, 1645 Neil Avenue, Columbus, OH 43210. E-mail:
or
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578
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Ferguson AD, Labunskyy VM, Fomenko DE, Araç D, Chelliah Y, Amezcua CA, Rizo J, Gladyshev VN, Deisenhofer J. NMR Structures of the Selenoproteins Sep15 and SelM Reveal Redox Activity of a New Thioredoxin-like Family. J Biol Chem 2006; 281:3536-43. [PMID: 16319061 DOI: 10.1074/jbc.m511386200] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Selenium has significant health benefits, including potent cancer prevention activity and roles in immune function and the male reproductive system. Selenium-containing proteins, which incorporate this essential micronutrient as selenocysteine, are proposed to mediate the positive effects of dietary selenium. Presented here are the solution NMR structures of the selenoprotein SelM and an ortholog of the selenoprotein Sep15. These data reveal that Sep15 and SelM are structural homologs that establish a new thioredoxin-like protein family. The location of the active-site redox motifs within the fold together with the observed localized conformational changes after thiol-disulfide exchange and measured redox potential indicate that they have redox activity. In mammals, Sep15 expression is regulated by dietary selenium, and either decreased or increased expression of this selenoprotein alters redox homeostasis. A physiological role for Sep15 and SelM as thiol-disulfide oxidoreductases and their contribution to the quality control pathways of the endoplasmic reticulum are discussed.
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Affiliation(s)
- Andrew D Ferguson
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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579
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Kulp MS, Frickel EM, Ellgaard L, Weissman JS. Domain Architecture of Protein-disulfide Isomerase Facilitates Its Dual Role as an Oxidase and an Isomerase in Ero1p-mediated Disulfide Formation. J Biol Chem 2006; 281:876-84. [PMID: 16368681 DOI: 10.1074/jbc.m511764200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Native disulfide bond formation in eukaryotes is dependent on protein-disulfide isomerase (PDI) and its homologs, which contain varying combinations of catalytically active and inactive thioredoxin domains. However, the specific contribution of PDI to the formation of new disulfides versus reduction/rearrangement of non-native disulfides is poorly understood. We analyzed the role of individual PDI domains in disulfide bond formation in a reaction driven by their natural oxidant, Ero1p. We found that Ero1p oxidizes the isolated PDI catalytic thioredoxin domains, A and A' at the same rate. In contrast, we found that in the context of full-length PDI, there is an asymmetry in the rate of oxidation of the two active sites. This asymmetry is the result of a dual effect: an enhanced rate of oxidation of the second catalytic (A') domain and the substrate-mediated inhibition of oxidation of the first catalytic (A) domain. The specific order of thioredoxin domains in PDI is important in establishing the asymmetry in the rate of oxidation of the two active sites thus allowing A and A', two thioredoxin domains that are similar in sequence and structure, to serve opposing functional roles as a disulfide isomerase and disulfide oxidase, respectively. These findings reveal how native disulfide folding is accomplished in the endoplasmic reticulum and provide a context for understanding the proliferation of PDI homologs with combinatorial arrangements of thioredoxin domains.
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Affiliation(s)
- Mohini S Kulp
- Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, 94158, USA
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580
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Li SJ, Hong XG, Shi YY, Li H, Wang CC. Annular arrangement and collaborative actions of four domains of protein-disulfide isomerase: a small angle X-ray scattering study in solution. J Biol Chem 2005; 281:6581-8. [PMID: 16407203 DOI: 10.1074/jbc.m508422200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We presented for the first time a small angle x-ray scattering study of intact protein-disulfide isomerase (PDI) in solution. The restored model revealed that PDI is a short and roughly elliptical cylinder with a molecular mass of 69 kDa and dimensions of 105 x 65 x 40 A, and the four thioredoxin-fold domains in the order a-b-b'-a' are arranged in an annular fashion. Atomic force microscope imaging also supported the finding that PDI appears as an approximately flat elliptical cylinder. A PDI species with apparent molecular mass of 116 kDa measured by using size-exclusion chromatography, previously assumed to be a dimer, was determined to exist mainly as a monomer by using analytical ultracentrifugation. The C-terminal fragment 441-491 contributed to the anomalous molecular mass determination of PDI by size-exclusion chromatography. The annular model of PDI accounted for the cooperative properties of the four domains in both the isomerase and chaperone functions of PDI.
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Affiliation(s)
- Sheng-jian Li
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences, Beijing, China
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581
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Hewett JW, Zeng J, Niland BP, Bragg DC, Breakefield XO. Dystonia-causing mutant torsinA inhibits cell adhesion and neurite extension through interference with cytoskeletal dynamics. Neurobiol Dis 2005; 22:98-111. [PMID: 16361107 DOI: 10.1016/j.nbd.2005.10.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 10/05/2005] [Accepted: 10/16/2005] [Indexed: 01/05/2023] Open
Abstract
Early onset torsion dystonia is a movement disorder inherited as an autosomal dominant syndrome with reduced penetrance. Symptoms appear to result from altered neuronal circuitry within the brain with no evidence of neuronal loss. Most cases are caused by loss of a glutamic acid residue in the AAA+ chaperone protein, torsinA, encoded in the DYT1 gene. In this study, torsinA was found to move in conjunction with vimentin in three cell culture paradigms-recovery from microtubule depolymerization, expression of a dominant-negative form of kinesin light chain and respreading after trypsinization. Co-immune precipitation studies revealed association between vimentin and torsinA in a complex including other cytoskeletal elements, actin and tubulin, as well as two proteins previously shown to interact with torsinA-the motor protein, kinesin light chain 1, and the nuclear envelope protein, LAP1. Morphologic and functional differences related to vimentin were noted in primary fibroblasts from patients carrying this DYT1 mutation as compared with controls, including an increased perinuclear concentration of vimentin and a delayed rate of adhesion to the substratum. Overexpression of mutant torsinA inhibited neurite extension in human neuroblastoma cells, with torsinA and vimentin immunoreactivity enriched in the perinuclear region and in cytoplasmic inclusions. Collectively, these studies suggest that mutant torsinA interferes with cytoskeletal events involving vimentin, possibly by restricting movement of these particles/filaments, and hence may affect development of neuronal pathways in the brain.
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Affiliation(s)
- Jeffrey W Hewett
- Molecular Neurogenetics Unit, Departments of Neurology and Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA 02114, USA
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582
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Kersteen EA, Barrows SR, Raines RT. Catalysis of protein disulfide bond isomerization in a homogeneous substrate. Biochemistry 2005; 44:12168-78. [PMID: 16142915 PMCID: PMC2526094 DOI: 10.1021/bi0507985] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein disulfide isomerase (PDI) catalyzes the rearrangement of nonnative disulfide bonds in the endoplasmic reticulum of eukaryotic cells, a process that often limits the rate at which polypeptide chains fold into a native protein conformation. The mechanism of the reaction catalyzed by PDI is unclear. In assays involving protein substrates, the reaction appears to involve the complete reduction of some or all of its nonnative disulfide bonds followed by oxidation of the resulting dithiols. The substrates in these assays are, however, heterogeneous, which complicates mechanistic analyses. Here, we report the first analysis of disulfide bond isomerization in a homogeneous substrate. Our substrate is based on tachyplesin I, a 17-mer peptide that folds into a beta hairpin stabilized by two disulfide bonds. We describe the chemical synthesis of a variant of tachyplesin I in which its two disulfide bonds are in a nonnative state and side chains near its N and C terminus contain a fluorescence donor (tryptophan) and acceptor (N(epsilon)-dansyllysine). Fluorescence resonance energy transfer from 280 to 465 nm increases by 28-fold upon isomerization of the disulfide bonds into their native state (which has a lower E(o') = -0.313 V than does PDI). We use this continuous assay to analyze catalysis by wild-type human PDI and a variant in which the C-terminal cysteine residue within each Cys-Gly-His-Cys active site is replaced with alanine. We find that wild-type PDI catalyzes the isomerization of the substrate with kcat/K(M) = 1.7 x 10(5) M(-1) s(-1), which is the largest value yet reported for catalysis of disulfide bond isomerization. The variant, which is a poor catalyst of disulfide bond reduction and dithiol oxidation, retains virtually all of the activity of wild-type PDI in catalysis of disulfide bond isomerization. Thus, the C-terminal cysteine residues play an insignificant role in the isomerization of the disulfide bonds in nonnative tachyplesin I. We conclude that catalysis of disulfide bond isomerization by PDI does not necessarily involve a cycle of substrate reduction/oxidation.
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Affiliation(s)
- Elizabeth A Kersteen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1544, USA
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583
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Bergeron A, Jorquera R, Orejuela D, Tanguay RM. Involvement of endoplasmic reticulum stress in hereditary tyrosinemia type I. J Biol Chem 2005; 281:5329-34. [PMID: 16317004 DOI: 10.1074/jbc.m506804200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hereditary tyrosinemia type I (HTI) is the most severe disease of the tyrosine degradation pathway. HTI is caused by a deficiency of fumarylacetoacetate hydrolase (FAH), the enzyme responsible for the hydrolysis of fumarylacetoacetate (FAA). As a result, there is an accumulation of metabolites such as maleylacetoacetate, succinylacetone, and FAA. The latter was shown to display mutagenic, cytostatic, and apoptogenic activities and to cause chromosomal instability. Herein, we demonstrate that FAA also causes a cellular insult leading to the endoplasmic reticulum (ER) stress signaling. Treatment of V79 Chinese hamster lung cells with an apoptogenic dose of FAA (100 mum) causes an early induction of the ER resident chaperone GRP78/BiP and a simultaneous phosphorylation of the eIF2alpha. FAA treatment also causes a subsequent induction of the proapoptotic CHOP (CEBP homologous protein) transcription factor as well as a late activation of caspase-12. Data obtained from fah(-/-) mice taken off the therapeutic 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3 cyclohexanedione drug are similar. However, in this mouse model, there is also an increase in proteasome activity indicative of ER-associated degradation. This difference observed between the two models may be due to the fact that the murine model measures the effects of all metabolites accumulating in hereditary tyrosinemia type I as opposed to the cellular model that only measures the effects of exogenous FAA.
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Affiliation(s)
- Anne Bergeron
- Laboratory of Cell and Developmental Genetics, Department of Medicine, Centre de Recherche sur la Fonction, la Structure, et l'Ingénierie des Protéines, Pavillon Marchand, Université Laval, Ste-Foy, Québec G1K 7P4, Canada
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584
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van Anken E, Braakman I. Versatility of the endoplasmic reticulum protein folding factory. Crit Rev Biochem Mol Biol 2005; 40:191-228. [PMID: 16126486 DOI: 10.1080/10409230591008161] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The endoplasmic reticulum (ER) is dedicated to import, folding and assembly of all proteins that travel along or reside in the secretory pathway of eukaryotic cells. Folding in the ER is special. For instance, newly synthesized proteins are N-glycosylated and by default form disulfide bonds in the ER, but not elsewhere in the cell. In this review, we discuss which features distinguish the ER as an efficient folding factory, how the ER monitors its output and how it disposes of folding failures.
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Affiliation(s)
- Eelco van Anken
- Department of Cellular Protein Chemistry, Bijvoet Center, Utrecht University, The Netherlands
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585
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Silvennoinen L, Koivunen P, Myllyharju J, Kilpeläinen I, Permi P. NMR assignment of the N-terminal domain a of the glycoprotein chaperone ERp57. JOURNAL OF BIOMOLECULAR NMR 2005; 33:136. [PMID: 16258833 DOI: 10.1007/s10858-005-2720-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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586
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Haugstetter J, Blicher T, Ellgaard L. Identification and Characterization of a Novel Thioredoxin-related Transmembrane Protein of the Endoplasmic Reticulum. J Biol Chem 2005; 280:8371-80. [PMID: 15623505 DOI: 10.1074/jbc.m413924200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The endoplasmic reticulum (ER) contains a number of thiol-disulfide oxidoreductases of the protein-disulfide isomerase (PDI) family that catalyze the formation of disulfide bonds in newly synthesized proteins. Here we describe the identification and characterization of a novel member of the human PDI family, TMX3 (thioredoxin-related transmembrane protein 3). The TMX3 gene encodes a protein of 454 amino acid residues that contains a predicted N-terminal signal sequence, a single domain with sequence similarity to thioredoxin and a CGHC active site sequence, a potential transmembrane domain, and a C-terminal KKKD tetrapeptide sequence that matches the classical KKXX-type consensus sequence for ER retrieval of type I transmembrane proteins. Endogenous TMX3 contains endoglycosidase H-sensitive glycans, localizes to the ER by immunofluorescence microscopy, and is present in the membrane fraction after alkaline extraction of the ER luminal content. The TMX3 transcript is found in a variety of tissues and is not up-regulated by the unfolded protein response. Circular dichroism spectroscopy of the recombinantly expressed luminal domain of TMX3 showed features typical of a properly folded protein of the alpha/beta type. The redox potential of recombinant luminal TMX3 was determined to -0.157 V, similar to the values previously found for PDI and ERp57. Interestingly, TMX3 showed oxidase activity, and in human tissue-culture cells the protein was found partially in the oxidized form, potentially suggesting a function of the protein as a dithiol oxidase.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Blotting, Northern
- Blotting, Western
- Catalysis
- Cell Line
- Cell Membrane/metabolism
- Cells, Cultured
- Chlorocebus aethiops
- Circular Dichroism
- Dose-Response Relationship, Drug
- Endoplasmic Reticulum/metabolism
- Exons
- Genetic Vectors
- Glutathione/chemistry
- Glycoside Hydrolases/chemistry
- Glycoside Hydrolases/metabolism
- HeLa Cells
- Humans
- Introns
- Kinetics
- Microscopy, Fluorescence
- Molecular Sequence Data
- Oxidation-Reduction
- Oxidoreductases/chemistry
- Oxidoreductases/metabolism
- Oxygen/metabolism
- Peptides/chemistry
- Plasmids/metabolism
- Protein Denaturation
- Protein Disulfide-Isomerases/biosynthesis
- Protein Disulfide-Isomerases/chemistry
- Protein Folding
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Recombinant Proteins/chemistry
- Sequence Homology, Amino Acid
- Spectrometry, Fluorescence
- Spectrophotometry
- Subcellular Fractions
- Thioredoxins/chemistry
- Time Factors
- Tissue Distribution
- Transcription, Genetic
- Ultraviolet Rays
- Up-Regulation
- Vero Cells
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587
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Koivunen P, Salo KEH, Myllyharju J, Ruddock LW. Three Binding Sites in Protein-disulfide Isomerase Cooperate in Collagen Prolyl 4-Hydroxylase Tetramer Assembly. J Biol Chem 2005; 280:5227-35. [PMID: 15590633 DOI: 10.1074/jbc.m412480200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-disulfide isomerase (PDI) is a modular polypeptide consisting of four domains, a, b, b', and a'. It is a ubiquitous protein folding catalyst that in addition functions as the beta-subunit in vertebrate collagen prolyl 4-hydroxylase (C-P4H) alpha(2)beta(2) tetramers. We report here that point mutations in the primary peptide substrate binding site in the b' domain of PDI did not inhibit C-P4H assembly. Based on sequence conservation, additional putative binding sites were identified in the a and a' domains. Mutations in these sites significantly reduced C-P4H tetramer assembly, with the a domain mutations generally having the greater effect. When the a or a' domain mutations were combined with the b' domain mutation I272W tetramer assembly was further reduced, and more than 95% of the assembly was abolished when mutations in the three domains were combined. The data indicate that binding sites in three PDI domains, a, b', and a', contribute to efficient C-P4H tetramer assembly. The relative contributions of these sites were found to differ between Caenorhabditis elegans C-P4H alphabeta dimer and human alpha(2)beta(2) tetramer formation.
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Affiliation(s)
- Peppi Koivunen
- Collagen Research Unit, Biocenter Oulu, and Department of Medical Biochemistry and Molecular Biology, University of Oulu, Oulu FIN-90014, Finland
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588
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Soldà T, Olivari S, Molinari M. Analyzing folding and degradation of metabolically labelled polypeptides by conventional and diagonal sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Biol Proced Online 2005; 7:136-43. [DOI: 10.1251/bpo111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 07/14/2005] [Accepted: 09/20/2005] [Indexed: 01/30/2023] Open
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