1
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In silico screening and exploration into phenotypic alterations of deleterious oncogenic single nucleotide polymorphisms in HSPB1 gene. Genomics 2021; 113:2812-2825. [PMID: 34129932 DOI: 10.1016/j.ygeno.2021.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 05/26/2021] [Accepted: 06/09/2021] [Indexed: 11/20/2022]
Abstract
A small heat shock protein, HSP27, encoded by HSPB1 gene strongly favors survival, proliferation and metastasis of cancer cells and its expression is dependent on post-translational modifications like phosphorylation. This study performed an extensive in silico screening of 20 deleterious non-synonymous SNPs in the coding region of HSPB1 gene, among which four were identified to be cancer associated. The SNP variant I181S introduced a new phosphorylation site in position 181, which might elevate the protein's activation potential. Emergence of other post-translational modifications was also observed in SNP variants: L144P and E130K.Significant conformational changes were observed in I181S, L144P and E130K SNP variants with respect to wild-type HSP27. These SNPs appear in one among 105 individuals, making them more susceptible towards cancer. This study would therefore, instigate development of novel biomarkers for cancer risk detection and would provide a detailed understanding towards varied cancer susceptibility of human population.
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2
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Morelli FF, Mediani L, Heldens L, Bertacchini J, Bigi I, Carrà AD, Vinet J, Carra S. An interaction study in mammalian cells demonstrates weak binding of HSPB2 to BAG3, which is regulated by HSPB3 and abrogated by HSPB8. Cell Stress Chaperones 2017; 22:531-540. [PMID: 28181153 PMCID: PMC5465030 DOI: 10.1007/s12192-017-0769-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/12/2022] Open
Abstract
The ten mammalian small heat shock proteins (sHSPs/HSPBs) show a different expression profile, although the majority of them are abundant in skeletal and cardiac muscles. HSPBs form hetero-oligomers and homo-oligomers by interacting together and complexes containing, e.g., HSPB2/HSPB3 or HSPB1/HSPB5 have been documented in mammalian cells and muscles. Moreover, HSPB8 associates with the Hsc70/Hsp70 co-chaperone BAG3, in mammalian, skeletal, and cardiac muscle cells. Interaction of HSPB8 with BAG3 regulates its stability and function. Weak association of HSPB5 and HSPB6 with BAG3 has been also reported upon overexpression in cells, supporting the idea that BAG3 might indirectly modulate the function of several HSPBs. However, it is yet unknown whether other HSPBs highly expressed in muscles such as HSPB2 and HSPB3 also bind to BAG3. Here, we report that in mammalian cells, upon overexpression, HSPB2 binds to BAG3 with an affinity weaker than HSPB8. HSPB2 competes with HSPB8 for binding to BAG3. In contrast, HSPB3 negatively regulates HSPB2 association with BAG3. In human myoblasts that express HSPB2, HSPB3, HSPB8, and BAG3, the latter interacts selectively with HSPB8. Combining these data, it supports the interpretation that HSPB8-BAG3 is the preferred interaction.
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Affiliation(s)
- Federica F Morelli
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Laura Mediani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Lonneke Heldens
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Jessika Bertacchini
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Ilaria Bigi
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Arianna Dorotea Carrà
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Jonathan Vinet
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy
| | - Serena Carra
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.
- Department of Cell Biology, University Medical Center Groningen; University of Groningen, Groningen, The Netherlands.
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3
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Sehgal SA, Mannan S, Ali S. Pharmacoinformatic and molecular docking studies reveal potential novel antidepressants against neurodegenerative disorders by targeting HSPB8. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:1605-18. [PMID: 27226709 PMCID: PMC4866741 DOI: 10.2147/dddt.s101929] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Charcot-Marie-Tooth (CMT) disease is an inherited peripheral neuromuscular disorder characterized by length-dependent and progressive degeneration of peripheral nerves, leading to muscular weakness. Research has shown that mutated HSPB8 may be responsible for depression, neurodegenerative disorders, and improper functioning of peripheral nerves, resulting in neuromuscular disorders like CMT. In the current work, a hybrid approach of virtual screening and molecular docking studies was followed by homology modeling and pharmacophore identification. Detailed screening analyses were carried out by 2-D similarity search against prescribed antidepressant drugs with physicochemical properties. LigandScout was employed to ascertain novel molecules and pharmacophore properties. In this study, we report three novel compounds that showed maximum binding affinity with HSPB8. Docking analysis elucidated that Met37, Ser57, Ser58, Trp60, Thr63, Thr114, Lys115, Asp116, Gly117, Val152, Val154, Leu186, Asp189, Ser190, Gln191, and Glu192 are critical residues for ligand-receptor interactions. Our analyses suggested paroxetine as a potent compound for targeting HSPB8. Selected compounds have more effective energy scores than the selected drug analogs. Additionally, site-directed mutagenesis could be significant for further analysis of the binding pocket. The novel findings based on an in silico approach may be momentous for potent drug design against depression and CMT.
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Affiliation(s)
- Sheikh Arslan Sehgal
- Department of Bioscience, COMSATS Institute of Information Technology, Sahiwal, Pakistan; State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China; University of Chinese Academy of Sciences, Beijing, People's Republic of China; Department of Bioinformatics and Biotechnology, International Islamic University, Islamabad, Pakistan
| | - Shazia Mannan
- Department of Bioscience, COMSATS Institute of Information Technology, Sahiwal, Pakistan
| | - Sannia Ali
- Department of Bioscience, COMSATS Institute of Information Technology, Sahiwal, Pakistan
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4
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López-González I, Carmona M, Arregui L, Kovacs GG, Ferrer I. αB-crystallin and HSP27 in glial cells in tauopathies. Neuropathology 2014; 34:517-26. [PMID: 24985029 DOI: 10.1111/neup.12134] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 03/16/2014] [Accepted: 05/07/2014] [Indexed: 12/11/2022]
Abstract
Tauopathies are neurodegenerative diseases characterized by hyper-phosphorylated tau deposition in neurons and glial cells. Chaperones, such as small heat shock proteins αB-crystallin and HSP27 highly expressed in normal glial cells, have been postulated as putative molecules preventing abnormal deposition and folding in glial cells in tauopathies. The objective of this work was to assess the expression of αB-crystallin, phosphorylated αB-crystallin at Ser59 and HSP27 in glial cells with and without tau deposits in progressive supranuclear palsy, corticobasal degeneration (CBD), argyrophilic grain disease (AGD), Pick's disease (PiD), Alzheimer's disease, frontotemporal lobar degeneration associated with mutations in the tau gene (FTLD-tau), globular glial tauopathy (GGT) and tauopathy in the elderly. Immunohistochemistry, and double-labeling immunofluorescence and confocal microscopy have been used for this purpose. Increased expression of αB-crystallin and phosphorylated αB-crystallin at Ser59 occurs in a subpopulation of glial cells with and without hyper-phosphorylated tau deposition in all the analyzed tauopathies, but their expression in neurons is restricted to ballooned neurons in CBD, AGD and PiD. HSP27 barely co-localizes with tau and with phosphorylated αB-crystallin at Ser59, thus making the formation of active dimers operating as chaperones unlikely. Results suggest a limited function of αB-crystallin and HSP27 in preventing abnormal tau protein deposition in glial cells and neurons; in addition, the expression of αB-crystallin phosphorylated at Ser59 may act as a protective factor in glial cells.
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Affiliation(s)
- Irene López-González
- Institut de Neuropatologia, IDIBELL-Hospital Universitari de Bellvitge, Hospitalet de Llobregat, CIBERNED (Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas), Universitat de Barcelona, Barcelona, Spain
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5
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Simon S, Dimitrova V, Gibert B, Virot S, Mounier N, Nivon M, Kretz-Remy C, Corset V, Mehlen P, Arrigo AP. Analysis of the dominant effects mediated by wild type or R120G mutant of αB-crystallin (HspB5) towards Hsp27 (HspB1). PLoS One 2013; 8:e70545. [PMID: 23950959 PMCID: PMC3741289 DOI: 10.1371/journal.pone.0070545] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 06/19/2013] [Indexed: 12/21/2022] Open
Abstract
Several human small heat shock proteins (sHsps) are phosphorylated oligomeric chaperones that enhance stress resistance. They are characterized by their ability to interact and form polydispersed hetero-oligomeric complexes. We have analyzed the cellular consequences of the stable expression of either wild type HspB5 or its cataracts and myopathies inducing R120G mutant in growing and oxidative stress treated HeLa cells that originally express only HspB1. Here, we describe that wild type and mutant HspB5 induce drastic and opposite effects on cell morphology and oxidative stress resistance. The cellular distribution and phosphorylation of these polypeptides as well as the oligomerization profile of the resulting hetero-oligomeric complexes formed by HspB1 with the two types of exogenous polypeptides revealed the dominant effects induced by HspB5 polypeptides towards HspB1. The R120G mutation enhanced the native size and salt resistance of HspB1-HspB5 complex. However, in oxidative conditions the interaction between HspB1 and mutant HspB5 was drastically modified resulting in the aggregation of both partners. The mutation also induced the redistribution of HspB1 phosphorylated at serine 15, originally observed at the level of the small oligomers that do not interact with wild type HspB5, to the large oligomeric complex formed with mutant HspB5. This phosphorylation stabilized the interaction of HspB1 with mutant HspB5. A dominant negative effect towards HspB1 appears therefore as an important event in the cellular sensitivity to oxidative stress mediated by mutated HspB5 expression. These observations provide novel data that describe how a mutated sHsp can alter the protective activity of another member of this family of chaperones.
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Affiliation(s)
- Stéphanie Simon
- Hôpital Henri Mondor University, Créteil, France
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Valeriya Dimitrova
- Department of Clinical Research, Division of Pediatric Hematology/Oncology, Insel Spital, Institute of Pathology, Bern University, Bern, Switzerland
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Benjamin Gibert
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
- Apoptosis Cancer and Development Laboratory, Lyon Cancer Research Center, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Claude Bernard University Lyon 1, Lyon, France
| | - Sophie Virot
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Nicole Mounier
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Mathieu Nivon
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Carole Kretz-Remy
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
| | - Véronique Corset
- Apoptosis Cancer and Development Laboratory, Lyon Cancer Research Center, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Claude Bernard University Lyon 1, Lyon, France
| | - Patrick Mehlen
- Apoptosis Cancer and Development Laboratory, Lyon Cancer Research Center, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Claude Bernard University Lyon 1, Lyon, France
| | - André-Patrick Arrigo
- CGphiMC, CNRS UMR 5534, Claude Bernard University Lyon 1, Villeurbanne, France
- Apoptosis Cancer and Development Laboratory, Lyon Cancer Research Center, INSERM U1052-CNRS UMR5286, Centre Léon Bérard, Claude Bernard University Lyon 1, Lyon, France
- * E-mail:
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6
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Ghayour-Mobarhan M, Saber H, Ferns GAA. The potential role of heat shock protein 27 in cardiovascular disease. Clin Chim Acta 2011; 413:15-24. [PMID: 21514288 DOI: 10.1016/j.cca.2011.04.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 04/03/2011] [Accepted: 04/05/2011] [Indexed: 12/13/2022]
Abstract
Heat shock proteins (Hsps) comprise several families of proteins expressed by a number of cell types following exposure to stressful environmental conditions that include heat, free radicals, toxins and ischemia, and are particularly involved in the recognition and renaturation of mis-folded proteins. Heat shock protein-27 (Hsp27) is a member of the small Hsp (sHsp) family with a molecular weight of approximately 27 KDa. In addition to its chaperoning functions, Hsp27 also appears to be involved in a diverse range of cellular functions, promoting cell survival through effects on the apoptotic pathway and plays important roles in cytoskeleton dynamics, cell differentiation and embryogenesis. Over the past two decades there has been an increasing interest in the relationship between Hsp27 and cardiovascular disease. Hsp27 is thought to exert an important role in the atherosclerotic process. Serum Hsp27 concentrations appear to be a biomarker of myocardial ischemia. In this review, we will focus on the possible protective and immuno-modulatory roles of Hsp27 in atherogenesis with special emphasis on their changes following acute coronary events and their potential as diagnostic and therapeutic targets.
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Affiliation(s)
- Majid Ghayour-Mobarhan
- Biochemistry and Nutrition Research Center and Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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7
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Stetler RA, Gao Y, Signore AP, Cao G, Chen J. HSP27: mechanisms of cellular protection against neuronal injury. Curr Mol Med 2010; 9:863-72. [PMID: 19860665 DOI: 10.2174/156652409789105561] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The heat shock protein (HSP) family has long been associated with a generalized cellular stress response, particularly in terms of recognizing and chaperoning misfolded proteins. While HSPs in general appear to be protective, HSP27 has recently emerged as a particularly potent neuroprotectant in a number of diverse neurological disorders, ranging from ALS to stroke. Although its robust protective effect on a number of insults has been recognized, the mechanisms and regulation of HSP27's protective actions are still undergoing intense investigation. On the basis of recent studies, HSP27 appears to have a dynamic and diverse range of function in cellular survival. This review provides a forum to compare and contrast recent literature exploring the protective mechanism and regulation of HSP27, focusing on neurological disorders in particular, as they represent a range from protein aggregate-associated diseases to acute stress.
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Affiliation(s)
- R A Stetler
- Department of Neurology, University of Pittsburgh, 507 South Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15261, USA
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8
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Santhoshkumar P, Murugesan R, Sharma KK. Deletion of (54)FLRAPSWF(61) residues decreases the oligomeric size and enhances the chaperone function of alphaB-crystallin. Biochemistry 2009; 48:5066-73. [PMID: 19388699 DOI: 10.1021/bi900085v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AlphaB-crystallin is a member of the small heat shock protein family and is known to have chaperone activity. Using a peptide scan approach, we previously determined that regions 42-57, 60-71, and 88-123 in alphaB-crystallin interact with alphaA-crystallin during heterooligomer formation. To further characterize the significance of the N-terminal domain of alphaB-crystallin, we prepared a deletion mutant that lacks residues (54)FLRAPSWF(61) (alphaBDelta54-61) and found that the absence of residues 54-61 in alphaB-crystallin significantly decreased the homooligomeric mass of alphaB-crystallin. The average oligomeric mass of wild-type alphaB-crystallin and of alphaBDelta54-61, calculated using multiangle light scattering, was 624 and 382 kDa, respectively. The mutant subunits aggregate to form smaller, less-compact oligomers with a 4-fold increase in subunit exchange rate. Deletion of the 54-61 region resulted in a 50% decrease in intrinsic tryptophan fluorescence. The alphaBDelta54-61 mutant showed a 2-fold increase in 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid (bis-ANS) binding as compared to the wild-type protein, suggesting increased hydrophobicity of the mutant protein. Accompanying the evidence of increased hydrophobicity in the deletion mutant was a 10-fold increase in antiaggregation activity. Homooligomers of 6HalphaA (750 kDa) readily exchanged subunits with alphaBDelta54-61 homooligomers at 37 degrees C, forming heterooligomers with an intermediate mass of 625 kDa. Our data suggest that residues (54)FLRAPSWF(61) contribute to the higher order assembly of alphaB-crystallin oligomers. Residues (54)FLRAPSWF(61) in alphaB-crystallin are not essential for target protein binding during chaperone action, but this region apparently has a role in the chaperone activity of native alphaB-crystallin.
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Affiliation(s)
- Puttur Santhoshkumar
- Department of Ophthalmology, University of Missouri, Columbia, Missouri 65212, USA
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9
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Support for a trimeric collar of myosin binding protein C in cardiac and fast skeletal muscle, but not in slow skeletal muscle. FEBS Lett 2008; 582:434-8. [PMID: 18201573 DOI: 10.1016/j.febslet.2008.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 12/19/2007] [Accepted: 01/02/2008] [Indexed: 11/20/2022]
Abstract
Myosin-binding protein C (MyBPC) is proposed to take on a trimeric collar arrangement around the thick filament backbone in cardiac muscle, based on interactions between cardiac MyBPC domains C5 and C8. We have now determined, using yeast two-hybrid and in vitro binding assays, that the C5:C8 interaction is not dependent on the 28-residue cardiac-specific insert in C5. Furthermore, an interaction of similar affinity occurs between domains C5 and C8 of fast skeletal muscle MyBPC, but not between these domains of the slow skeletal muscle protein. These data have implications for the role and quaternary structure of MyBPC in skeletal muscle.
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10
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MacIntyre DA, Tyson EK, Read M, Smith R, Yeo G, Kwek K, Chan EC. Contraction in human myometrium is associated with changes in small heat shock proteins. Endocrinology 2008; 149:245-52. [PMID: 17916631 DOI: 10.1210/en.2007-0662] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The myometrium undergoes substantial remodeling at the time of labor including rearrangement of the cellular contractile machinery. The regulation of this process in human myometrium at the time of labor is poorly defined, but evidence in other muscle types suggests modulation by small heat shock proteins (sHSP). The aim of this study was to investigate whether similar changes in sHSP occur in the myometrium at labor. Using a quantitative proteomic approach (two-dimensional difference gel electrophoresis), we found a 69% decrease in the sHSP alphaB-crystallin in the myometrium at labor plus multiple isoforms of HSP27. Immunoblotting using phosphospecific HSP27 antibodies (HSP27-serine15, -78, and -82) detected marked changes in HSP27 phosphorylation at labor. Although total HSP27 levels were unchanged, HSP27-Ser15 was 3-fold higher at labor. Coimmunoprecipitation studies showed that HSP27 coprecipitates with alphaB-crystallin and also smooth muscle alpha-actin. Coimmunofluorescence studies demonstrated a relocation of HSP27 from the perinuclear region to the actin cytoskeleton at labor. The functional significance of these changes was demonstrated in vitro where myometrial strips stimulated to contract with oxytocin exhibited increased HSP27-Ser15 phosphorylation. Our findings provide data consistent with a novel pathway regulating human myometrial contraction at labor and identify HSP27 and alphaB-crystallin as potential targets for future tocolytic design.
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Affiliation(s)
- David A MacIntyre
- Mothers and Babies Research Centre, The University of Newcastle, John Hunter Hospital, 1 Lookout Road, New Lambton Heights, Newcastle 2305, Australia
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11
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Liu BF, Liang JJN. Protein-protein interactions among human lens acidic and basic beta-crystallins. FEBS Lett 2007; 581:3936-42. [PMID: 17662718 PMCID: PMC2045703 DOI: 10.1016/j.febslet.2007.07.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 07/05/2007] [Indexed: 11/18/2022]
Abstract
Human lens beta-crystallin contains four acidic (betaA1-->betaA4) and three basic (betaB1-->betaB3) subunits. They oligomerize in the lens, but it is uncertain which subunits are involved in the oligomerization. We used a two-hybrid system to detect protein-protein interactions systematically. Proteins were also expressed for some physicochemical studies. The results indicate that all acidic-basic pairs (betaA-betaB) except betaA4-betaBs pairs show strong hetero-molecular interactions. For acidic or basic pairs, only two pairs (betaA1-betaA1 and betaA3-betaA3) show strong self-association. betaA2 and betaA4 show very weak self-association, which arises from their low solubility. Confocal fluorescence microscopy shows enormous protein aggregates in betaA2- or betaA4-crystallin transfected cells. However, coexpression with betaB2-crystallin decreased both the number and size of aggregates. Circular dichroism indicates subtle differences in conformation among beta-crystallins that may have contributed to the differences in interactions.
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Affiliation(s)
| | - Jack J.-N. Liang
- Corresponding author. Fax: +1 617 278 0556. E-mail address: (J.J.-N. Liang)
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12
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Fontaine JM, Sun X, Hoppe AD, Simon S, Vicart P, Welsh MJ, Benndorf R. Abnormal small heat shock protein interactions involving neuropathy‐associated HSP22 (HSPB8) mutants. FASEB J 2006; 20:2168-70. [PMID: 16935933 DOI: 10.1096/fj.06-5911fje] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Two mutations (K141E, K141N) in the small heat shock protein (sHSP) HSP22 (HSPB8) are associated with the inherited peripheral motor neuron disorders distal hereditary motor neuropathy type II and axonal Charcot-Marie-Tooth disease type 2L. HSP22 is known to form homodimers, heterodimers with other sHSPs, and larger oligomers. In an effort to elucidate the cellular basis for these diseases, we have determined the ability of mutant HSP22 to interact with itself, with wild-type HSP22, and with other sHSPs that are abundant in neurons. Using the yeast two-hybrid method, quantitative fluorescence resonance energy transfer in live cells, and cross-linking, we found aberrantly increased interactions of mutant HSP22 forms with themselves, with wild-type HSP22, and with the other sHSPs, alphaB-crystallin, and HSP27. Interaction with HSP20 was not affected by the mutations. The data suggest that each mutant form of HSP22 has a characteristic pattern of abnormal interaction properties. A mutation (S135F) in HSP27 that is also associated with these disorders showed increased interaction with wild-type HSP22 also, suggesting linkage of these two etiologic factors, HSP22 and HSP27, into one common pathway. Increased interactions involving mutant sHSPs may be the molecular basis for their increased tendency to form cytoplasmic protein aggregates, and for the occurrence of the associated neuropathies.
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Affiliation(s)
- Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Pl., Ann Arbor, MI 48109-2200, USA
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13
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Liang JJ, Liu BF. Fluorescence resonance energy transfer study of subunit exchange in human lens crystallins and congenital cataract crystallin mutants. Protein Sci 2006; 15:1619-27. [PMID: 16751613 PMCID: PMC2242568 DOI: 10.1110/ps.062216006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Lens alpha-crystallin is an oligomeric protein with a molecular mass of 500-1000 kDa and a polydispersed assembly. It consists of two types of subunits, alphaA and alphaB, each with a molecular mass of 20 kDa. The subunits also form homo-oligomers in some other tissues and in vitro. Their quaternary structures, which are dynamic and characterized by subunit exchange, have been studied by many techniques, including fluorescence resonance energy transfer (FRET) and mass spectrometry analysis. The proposed mechanism of subunit exchange has been either by dissociation/association of monomeric subunits or by rapid equilibrium between oligomers and suboligomers. To explore the nature of subunit exchange further, we performed additional FRET measurements and analyses using a fluorescent dye-labeled W9F alphaA-crystallin as the acceptor probe and Trp in other crystallins (wild-type and R116C alphaA, wild-type and R120G alphaB, wild-type and Q155* betaB2) as the donor probe and calculated the transfer efficiency, Förster distance, and average distance between two probes. The results indicate only slight decreased efficiency and increased distance between two probes for the R116C alphaA and R120G alphaB mutations despite conformational changes.
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Affiliation(s)
- Jack J Liang
- Ophthalmic Research/Surgery, Brigham and Women's Hospital, Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA.
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14
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Oya-Ito T, Liu BF, Nagaraj RH. Effect of methylglyoxal modification and phosphorylation on the chaperone and anti-apoptotic properties of heat shock protein 27. J Cell Biochem 2006; 99:279-91. [PMID: 16615138 DOI: 10.1002/jcb.20781] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Heat shock protein 27 (Hsp27) is a stress-inducible protein in cells that functions as a molecular chaperone and also as an anti-apoptotic protein. Methylglyoxal (MGO) is a reactive dicarbonyl compound produced from cellular glycolytic intermediates that reacts non-enzymatically with proteins to form products such as argpyrimidine. We found considerable amount of Hsp27 in phosphorylated form (pHsp27) in human cataractous lenses. pHsp27 was the major argpyrimidine-modified protein in brunescent cataractous lenses. Modification by MGO enhanced the chaperone function of both pHsp27 and native Hsp27, but the effect on Hsp27 was at least three-times greater than on pHsp27. Phosphorylation of Hsp27 abolished its chaperone function. Transfer of Hsp27 using a cationic lipid inhibited staurosporine (SP)-induced apoptotic cell death by 53% in a human lens epithelial cell line (HLE B-3). MGO-modified Hsp27 had an even greater effect (62% inhibition). SP-induced reactive oxygen species in HLE-B3 cells was significantly lower in cells transferred with MGO-modified Hsp27 when compared to native Hsp27. In vitro incubation experiments showed that MGO-modified Hsp27 reduced the activity of caspase-9, and MGO-modified pHsp27 reduced activities of both caspase-9 and caspase-3. Based on these results, we propose that Hsp27 becomes a better anti-apoptotic protein after modification by MGO, which may be due to multiple mechanisms that include enhancement of chaperone function, reduction in oxidative stress, and inhibition of activity of caspases. Our results suggest that MGO modification and phosphorylation of Hsp27 may have important consequences for lens transparency and cataract development.
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Affiliation(s)
- Tomoko Oya-Ito
- Department of Ophthalmology, Case Western Reserve University, Cleveland, Ohio
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15
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Fontaine JM, Sun X, Benndorf R, Welsh MJ. Interactions of HSP22 (HSPB8) with HSP20, αB-crystallin, and HSPB3. Biochem Biophys Res Commun 2005; 337:1006-11. [PMID: 16225851 DOI: 10.1016/j.bbrc.2005.09.148] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
Seven of the 10 mammalian small heat shock proteins (sHSP) are expressed in muscle where they constitute 3% or more of total protein. sHSPs interact with one another, and these interactions are believed to be important for their functions. In cell types expressing multiple sHSPs, it is of interest to know which sHSPs interact with one another. We have previously shown that HSP22 interacts with itself as well as with HSP27, MKBP, and cvHSP. Using yeast two-hybrid assays and Förster resonance energy transfer microscopy, we now show that HSP22 also can interact with two additional members of the sHSP family, alphaB-crystallin and HSP20. We also show that HSP22 is found in HPLC fractions of primate cardiac muscle containing high molecular weight complexes that include alphaB-crystallin and HSP20. Our results suggest that a variety of oligomers composed of different proportions of different sHSPs may form in cell types expressing multiple sHSPs.
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Affiliation(s)
- Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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16
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Mao L, Bryantsev AL, Chechenova MB, Shelden EA. Cloning, characterization, and heat stress-induced redistribution of a protein homologous to human hsp27 in the zebrafish Danio rerio. Exp Cell Res 2005; 306:230-41. [PMID: 15878347 DOI: 10.1016/j.yexcr.2005.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 02/10/2005] [Accepted: 02/10/2005] [Indexed: 10/25/2022]
Abstract
Hsp27 is a small heat shock protein (shsp) regulating stress tolerance and increasingly thought to play roles in tissue homeostasis and differentiation. The zebrafish Danio rerio is an important model for the study of developmental processes, but little is known regarding shsps in this animal. Here, we report the sequence, expression, regulation, and function of a zebrafish protein (zfHsp27) homologous to human Hsp27. zfHsp27 contains three conserved phosphorylatable serines and a cysteine important for regulation of apoptosis, but it lacks much of a C-terminal tail domain and shows low homology in two putative actin interacting domains that are features of mammalian Hsp27. zfHsp27 mRNA is most abundant in adult skeletal muscle and heart and is upregulated during early embryogenesis. zfHsp27 expressed in mammalian fibroblasts was phosphorylated in response to heat stress and anisomycin, and this phosphorylation was prevented by treatment with SB202190, an inhibitor of p38 MAPK. Expression of zfHsp27 and human Hsp27 in mammalian fibroblasts promoted a similar degree of tolerance to heat stress. zfHsp27 fusion proteins entered the nucleus and associated with the cytoskeleton of heat stressed cells in vitro and in zebrafish embryos. These results reveal conservation in regulation and function of mammalian and teleost Hsp27 proteins and define zebrafish as a new model for the study of Hsp27 function.
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Affiliation(s)
- Li Mao
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, WA 99164-4234, USA
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17
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Sun X, Fontaine JM, Rest JS, Shelden EA, Welsh MJ, Benndorf R. Interaction of Human HSP22 (HSPB8) with Other Small Heat Shock Proteins. J Biol Chem 2004; 279:2394-402. [PMID: 14594798 DOI: 10.1074/jbc.m311324200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian small heat shock proteins (sHSP) are abundant in muscles and are implicated in both muscle function and myopathies. Recently a new sHSP, HSP22 (HSPB8, H11), was identified in the human heart by its interaction with HSP27 (HSPB1). Using phylogenetic analysis we show that HSP22 is a true member of the sHSP superfamily. sHSPs interact with each other and form homo- and hetero-oligomeric complexes. The function of these complexes is poorly understood. Using gel filtration HPLC, the yeast two-hybrid method, immunoprecipitation, cross-linking, and fluorescence resonance energy transfer microscopy, we report that (i). HSP22 forms high molecular mass complexes in the heart, (ii). HSP22 interacts with itself, cvHSP (HSPB7), MKBP (HSPB2) and HSP27, and (iii). HSP22 has two binding domains (N- and C-terminal) that are specific for different binding partners. HSP22 homo-dimers are formed through N-N and N-C interactions, and HSP22-cvHSP hetero-dimers through C-C interaction. HSP22-MKBP and HSP22-HSP27 hetero-dimers involve the N and C termini of HSP22 and HSP27, respectively, but appear to require full-length protein as a binding partner.
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Affiliation(s)
- Xiankui Sun
- Departments of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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18
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Fu L, Liang JJN. Enhanced stability of alpha B-crystallin in the presence of small heat shock protein Hsp27. Biochem Biophys Res Commun 2003; 302:710-4. [PMID: 12646227 DOI: 10.1016/s0006-291x(03)00257-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lens alpha-crystallin, alpha A- and alpha B-crystallin, and Hsp27 are members of the small heat shock protein family. Both alpha A- and alpha B-crystallin are expressed in the lens and serve as structural proteins and as chaperones, but alpha B-crystallin is also expressed in nonlenticular organs where Hsp27, rather than alpha A-crystallin, is expressed along with alpha B-crystallin. It is not known what additional function Hsp27 has besides as a heat shock protein, but it may serve, as alpha A-crystallin does in the lens, to stabilize alpha B-crystallin. In this study, we investigate aspects on conformation and thermal stability for the mixture of Hsp27 and alpha B-crystallin. Size exclusion chromatography, circular dichroism (CD), and light scattering measurements indicated that Hsp27 prevented alpha B-crystallin from heat-induced structural changes and high molecular weight (HMW) aggregation. The results indicate that Hsp27 indeed promotes stability of alpha B-crystallin.
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Affiliation(s)
- Ling Fu
- Center for Ophthalmic Research, Brigham and Women's Hospital, and Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
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19
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Plesofsky N, Brambl R. Analysis of interactions between domains of a small heat shock protein, Hsp30 of Neurospora crassa. Cell Stress Chaperones 2002; 7:374-86. [PMID: 12653482 PMCID: PMC514837 DOI: 10.1379/1466-1268(2002)007<0374:aoibdo>2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The alpha-crystallin-related, small heat shock proteins (sHsps), despite their overall variability in sequence, have discrete regions of conserved sequence that are involved in structural organization, as well as nonconserved regions that may perform similar roles in each protein. Recent X-ray diffraction analyses of an archeal and a plant sHsp have revealed both similarities and differences in how they are organized, suggesting that there is variability, particularly in the oligomeric organization of sHsps. As an adjunct to crystallographic analysis of sHsp structure, we employed the yeast 2-hybrid system to detect interactions between peptide regions of the sHsp of Neurospora crassa, Hsp30. We found that the conserved alpha-crystallin domain can be divided into N-terminal and C-terminal subdomains that interact strongly with one another. This interaction likely represents the tertiary contacts of the monomer that were visualized in the crystallographic structures of MjHsp16.5 and wheat Hsp16.9. The conserved sHsp monomeric fold is apparently determined by these regions of conserved sequence. We found that the C-terminal portion of the alpha-crystallin domain also interacts with itself in 2-hybrid assays; however, this interaction requires peptide extension into the semiconserved carboxyl tail. This C-terminal association may represent a principal contact site between dimers that contributes to higher-order assembly, as seen for the crystallized sHsps.
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Affiliation(s)
- Nora Plesofsky
- Department of Plant Biology, 1445 Gortner Avenue, The University of Minnesota, Saint Paul, MN 55108, USA.
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20
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Kuczynska-Wisnik D, Kçdzierska S, Matuszewska E, Lund P, Taylor A, Lipinska B, Laskowska E. The Escherichia coli small heat-shock proteins IbpA and IbpB prevent the aggregation of endogenous proteins denatured in vivo during extreme heat shock. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1757-1765. [PMID: 12055295 DOI: 10.1099/00221287-148-6-1757] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The roles of the Escherichia coli IbpA and IbpB chaperones in protection of heat-denatured proteins against irreversible aggregation in vivo were investigated. Overproduction of IbpA and IbpB resulted in stabilization of the denatured and reversibly aggregated proteins (the S fraction), which could be isolated from E. coli cells by sucrose gradient centrifugation. This finding is in agreement with the present model of the small heat-shock proteins' function, based mainly on in vitro studies. Deletion of the ibpAB operon resulted in almost twofold increase in protein aggregation and in inactivation of an enzyme (fructose-1,6-biphosphate aldolase) in cells incubated at 50 degrees C for 4 h, decreased efficiency of the removal of protein aggregates formed during prolonged incubation at 50 degrees C and affected cell viability at this temperature. IbpA/B proteins were not needed for removal of protein aggregates or for the enzyme protection/renaturation in cells heat shocked at 50 degrees C for 15 min. These results show that the IbpA/B proteins are required upon an extreme, long-term heat shock. Overproduction of IbpA but not IbpB caused an increase of the level of beta-lactamase precursor, which was localized in the S fraction, together with the IbpA protein, which suggests that the unfolded precursor binds to IbpA but not to IbpB. Although in the wild-type cells both E. coli small heat-shock proteins are known to localize in the S fraction, only 2% of total IbpB co-localized with the aggregated proteins in the absence of IbpA, while in the absence of IbpB, the majority of IbpA was present in the aggregates fraction.
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Affiliation(s)
| | - Sabina Kçdzierska
- Department of Biochemistry, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1
| | - Ewelina Matuszewska
- Department of Biochemistry, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1
| | - Peter Lund
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK2
| | - Alina Taylor
- Department of Molecular Biology, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland3
| | - Barbara Lipinska
- Department of Biochemistry, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1
| | - Ewa Laskowska
- Department of Biochemistry, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland1
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21
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Nédellec P, Edling Y, Perret E, Fardeau M, Vicart P. Glucocorticoid treatment induces expression of small heat shock proteins in human satellite cell populations: consequences for a desmin-related myopathy involving the R120G alpha B-crystallin mutation. Neuromuscul Disord 2002; 12:457-65. [PMID: 12031619 DOI: 10.1016/s0960-8966(01)00306-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
A missense mutation (R120G) of the molecular chaperone alpha B-crystallin has recently been linked to a familial form of desmin-related myopathy characterized by intrasarcoplasmic aggregates of desmin. It was previously demonstrated that the mutant R120G had a defective chaperone-like function. However, the cellular and physiopathological consequences of R120G mutant expression in human muscle cells are as yet unclear. Thus, we developed a cellular model for the study of this R120G alpha B-crystallin-related desmin-related myopathy. We demonstrate that dexamethasone enhances alpha B-crystallin and HSP27 expression in normal and desmin-related myopathy-derived muscle cells. In the undifferentiated desmin-related myopathy satellite cell population no intracytoplasmic aggregates were observed. However, in differentiated satellite cells derived from a related myopathy patient, we observed an enhanced plasma membrane localization of alpha B-crystallin following glucocorticoid. We also observed that the protective effect against stress of alpha B-crystallin is altered upon glucocorticoid-induced small heat shock protein expression for the desmin-related myopathy-derived cells.
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Affiliation(s)
- Patrick Nédellec
- Laboratoire Cytosquelette et Développement, Université Paris VI, CNRS UMR 7000, Faculté de Médecine Pitié-Salpêtrière, 105 Boulevard De l'Hôpital, 75634 Cedex 13, Paris, France
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22
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Abstract
Actin and small heat shock proteins (sHsps) are ubiquitous and multifaceted proteins that exist in 2 reversible forms, monomers and multimers, ie, the microfilament of the cytoskeleton and oligomers of the sHsps, generally, supposed to be in a spherical and hollow form. Two situations are described in the literature, where the properties of actin are modulated by sHsps; the actin polymerization is inhibited in vitro by some sHsps acting as capping proteins, and the actin cytoskeleton is protected by some sHsps against the disruption induced by various stressful conditions. We propose that a direct actin-sHsp interaction occurs to inhibit actin polymerization and to participate in the in vivo regulation of actin filament dynamics. Protection of the actin cytoskeleton would result from an F-actin-sHsp interaction in which microfilaments would be coated by small oligomers of phosphorylated sHsps. Both proteins share common structural motives suggesting direct binding sites, but they remain to be demonstrated. Some sHsps would behave with the actin cytoskeleton as actin-binding proteins capable of either capping a microfilament when present as a nonphosphorylated monomer or stabilizing and protecting the microfilament when organized in small, phosphorylated oligomers.
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Affiliation(s)
- Nicole Mounier
- Laboratoire du Stress Oxydant, Chaperons et Apoptose, Centre de Génétique Moléculaire et Cellulaire (UMR-CNRS 5534), Université Claude Bernard Lyon1, Villeurbanne, France.
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23
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Narberhaus F. Alpha-crystallin-type heat shock proteins: socializing minichaperones in the context of a multichaperone network. Microbiol Mol Biol Rev 2002; 66:64-93; table of contents. [PMID: 11875128 PMCID: PMC120782 DOI: 10.1128/mmbr.66.1.64-93.2002] [Citation(s) in RCA: 399] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alpha-crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. Subsequently, they have been found in many, but not all, members of the Archaea, Bacteria, and Eucarya. Most members of the diverse alpha-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kDa; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the so-called alpha-crystallin domain; and (iv) molecular chaperone activity. Since alpha-crystallins are induced by a temperature upshift in many organisms, they are often referred to as small heat shock proteins (sHsps) or, more accurately, alpha-Hsps. Alpha-crystallins are integrated into a highly flexible and synergistic multichaperone network evolved to secure protein quality control in the cell. Their chaperone activity is limited to the binding of unfolding intermediates in order to protect them from irreversible aggregation. Productive release and refolding of captured proteins into the native state requires close cooperation with other cellular chaperones. In addition, alpha-Hsps seem to play an important role in membrane stabilization. The review compiles information on the abundance, sequence conservation, regulation, structure, and function of alpha-Hsps with an emphasis on the microbial members of this chaperone family.
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Affiliation(s)
- Franz Narberhaus
- Institut für Mikrobiologie, Eidgenössische Technische Hochschule, CH-8092 Zürich, Switzerland.
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24
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Fu L, Liang JJN. Detection of protein-protein interactions among lens crystallins in a mammalian two-hybrid system assay. J Biol Chem 2002; 277:4255-60. [PMID: 11700327 DOI: 10.1074/jbc.m110027200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Crystallin consists of two subunits, alphaA and alphaB, and each can form an oligomer by itself or with the other. The aggregation arises from interdomain interactions. However, it is not known whether such interactions also exist among alpha-, beta-, and gamma-crystallins. This heterogeneous crystallin interaction is far weaker than the homogeneous crystallin interaction and is difficult to detect by conventional spectroscopic measurements. We used a mammalian two-hybrid system in this study. The major crystallin components, alphaA-, alphaB-, betaB2-, and gammaC-crystallin genes, were subcloned into the DNA binding domain and transcription activation domain vectors of the two-hybrid system, and they were cotransfected along with a chloramphenicol acetyltransferase (CAT) reporter vector into HeLa cells. Chloramphenicol acetyltransferase activity indicated that there were interactions between alphaA- (or alphaB-) and betaB2- or gammaC-crystallins but with an intensity of one-third that of alphaA-alphaB interactions. Hsp27, a member of the family of the small heat-shock proteins, showed a similar interaction property with alphaB-crystallin. Using the N- and C-terminal domain-truncated mutants, we demonstrated that both domains were important in the alphaA-crystallin self-interaction, but that only the C-terminal domain was important in the alphaB-crystallin self-interaction. These results show that the two-hybrid system can detect interactions among various crystallins and may be used in mapping interaction domains.
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Affiliation(s)
- Ling Fu
- Center for Ophthalmic Research, Brigham and Women's Hospital, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02115, USA
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25
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Abstract
Heat shock protein-27 (Hsp27) is known to function as both a stress-inducible molecular chaperone and regulator of actin polymerization. For many cells in the cochlea, actin is part of the cytoskeleton and plays an important role in the maintenance of cochlear function. To understand the molecular processes by which the cochlear actin cytoskeleton is maintained and regulated during normal auditory function, we examined the expression and localization of Hsp27 in the normal rat cochlea. Reverse transcription-polymerase chain reaction and Western blot showed constitutive expression of Hsp27 in the normal rat cochlea. Immunofluorescence microscopy showed Hsp27-like staining is localized to the cuticular plate and lateral wall of outer hair cells. Hsp27-like immunostaining is also found in tension fibroblasts, in the root cells of the spiral limbus and in Reissner's membrane. The presence of Hsp27 in the actin-rich tension fibroblasts and outer hair cells suggests a potential role in the regulation and maintenance of the actin cytoskeleton in these cells. The presence of high levels of constitutive Hsp27 may also provide a mechanism for pre-protecting these cells against environmental stressors.
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Affiliation(s)
- Elena V Leonova
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor 48109-0506, USA
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26
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Jia Y, Ransom RF, Shibanuma M, Liu C, Welsh MJ, Smoyer WE. Identification and characterization of hic-5/ARA55 as an hsp27 binding protein. J Biol Chem 2001; 276:39911-8. [PMID: 11546764 DOI: 10.1074/jbc.m103510200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
hsp27 has been reported to participate in a wide variety of activities, including resistance to thermal and metabolic stress, regulation of growth and differentiation, and acting as a molecular chaperone or a regulator of actin polymerization. We hypothesized that these diverse functions are regulated in a cell- or tissue-specific manner via interaction with various binding proteins. To investigate this hypothesis, we used hsp27 as a "bait" to screen a yeast two-hybrid cDNA library from rat kidney glomeruli and identified a novel hsp27 binding protein, hic-5 (also known as ARA55), a focal adhesion protein and steroid receptor co-activator. Biochemical interaction between hsp27 and hic-5 was confirmed by co-immunoprecipitation, and critical protein.protein interaction regions were mapped to the hic-5 LIM domains and the hsp27 C-terminal domain. Initial analysis of the functional role of hsp27.hic-5 interaction revealed that hic-5 significantly inhibited the protection against heat-induced cell death conferred by hsp27 overexpression in co-transfected 293T cells. In contrast, when a non-hsp27-interacting hic-5 truncation mutant (hic-5/DeltaLIM4) was co-expressed with hsp27, the hic-5 inhibition of hsp27 protection was absent. We conclude that hic-5 is a true hsp27 binding protein and inhibits the ability of hsp27 to provide protection against heat shock in an interaction-dependent manner.
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Affiliation(s)
- Y Jia
- Cellular and Molecular Biology Program, Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, USA
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27
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Benndorf R, Sun X, Gilmont RR, Biederman KJ, Molloy MP, Goodmurphy CW, Cheng H, Andrews PC, Welsh MJ. HSP22, a new member of the small heat shock protein superfamily, interacts with mimic of phosphorylated HSP27 ((3D)HSP27). J Biol Chem 2001; 276:26753-61. [PMID: 11342557 DOI: 10.1074/jbc.m103001200] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most of the members of the superfamily of mammalian small heat shock or stress proteins are abundant in muscles where they play a role in muscle function and maintenance of muscle integrity. One member of this protein superfamily, human HSP27, is rapidly phosphorylated on three serine residues (Ser(15), Ser(78), and Ser(82)) during cellular response to a number of extracellular factors. To understand better the role of HSP27, we performed a yeast two-hybrid screen of a human heart cDNA library for HSP27-interacting proteins. By using the triple aspartate mutant, a mimic of phosphorylated HSP27, as "bait" construct, a protein with a molecular mass of 21.6 kDa was identified as an HSP27-binding protein. Sequence analysis revealed that this new protein shares an overall sequence identity of 33% with human HSP27. This protein also contains the alpha-crystallin domain in its C-terminal half, a hallmark of the superfamily of small stress proteins. Thus, the new protein itself is a member of this protein superfamily, and consequently we designated it HSP22. According to the two-hybrid data, HSP22 interacts preferentially with the triple aspartate form of HSP27 as compared with wild-type HSP27. HSP22 is expressed predominantly in muscles. In vitro, HSP22 is phosphorylated by protein kinase C (at residues Ser(14) and Thr(63)) and by p44 mitogen-activated protein kinase (at residues Ser(27) and Thr(87)) but not by MAPKAPK-2.
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Affiliation(s)
- R Benndorf
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
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28
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Hong S, Choi G, Park S, Chung AS, Hunter E, Rhee SS. Type D retrovirus Gag polyprotein interacts with the cytosolic chaperonin TRiC. J Virol 2001; 75:2526-34. [PMID: 11222675 PMCID: PMC115874 DOI: 10.1128/jvi.75.6.2526-2534.2001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The carboxy terminus-encoding portion of the gag gene of Mason-Pfizer monkey virus (M-PMV), the prototype immunosuppressive primate type D retrovirus, encodes a 36-amino-acid, proline-rich protein domain that, in the mature virion, becomes the p4 capsid protein. The p4 domain has no known role in M-PMV replication. We found that two mutants with premature termination codons that remove half or all of the p4 domain produced lower levels of stable Gag protein and of self-assembled capsids. Interestingly, yeast two-hybrid screening revealed that p4 specifically interacted with TCP-1gamma, a subunit of the chaperonin TRiC (TCP-1 ring complex). TRiC is a cytosolic chaperonin that is known to be involved in both folding and subunit assembly of a variety of cellular proteins. TCP-1gamma also associated with high specificity with the M-PMV pp24/16-p12 domain and human immunodeficiency virus p6. Moreover, in cells, Gag polyprotein associated with the TRiC chaperonin complex and this association depended on ATP hydrolysis. In the p4 truncation mutants, the Gag-TRiC association was significantly reduced. These results strongly suggest that cytosolic chaperonin TRiC is involved in Gag folding and/or capsid assembly. We propose that TRiC associates transiently with nascent M-PMV Gag molecules to assist in their folding. Consequently, properly folded Gag molecules carry out the intermolecular interactions involved in self-assembly of the immature capsid.
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Affiliation(s)
- S Hong
- Laboratory of Molecular Virology, Samsung Biomedical Research Institute, Seoul, Korea
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29
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Kirschner M, Winkelhaus S, Thierfelder JM, Nover L. Transient expression and heat-stress-induced co-aggregation of endogenous and heterologous small heat-stress proteins in tobacco protoplasts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2000; 24:397-411. [PMID: 11069712 DOI: 10.1046/j.1365-313x.2000.00887.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Heat-stress granules (HSG) are highly ordered, cytoplasmic chaperone complexes found in all heat-stressed plant cells. We have developed an experimental system involving expression of cytosolic class I and class II small heat-stress proteins (Hsps) of pea, Arabidopsis and tomato in tobacco protoplasts to study the structural prerequisites for the assembly of HSG or HSG-like complexes. Class I and class II small Hsps formed class-specific dodecamers of 210-280 kDa, which, upon heat stress, were incorporated into HSG complexes. Interestingly, class II dodecamers alone could form HSG-like complexes (auto-aggregation), whereas class I dodecamers could do so only in the presence of class II proteins (recruitment). By analysing C-terminal deletion forms of Hsp17 class II, we obtained evidence that the intact C-terminus is critical for the oligomerization state, for the heat-stress-induced auto-aggregation and for recruitment of class I proteins. The class-specific formation of dimers as a prerequisite for oligomerization was analysed by the yeast two-hybrid system. In the presence of the endogenous (tobacco) set of heat-stress-induced proteins, all heterologous class I and class II proteins were incorporated into HSG complexes, whose ultrastructure was different from that of complexes formed by class I and class II proteins alone. Although other, more distantly related, members of the Hsp20 family, i.e. the plastidic pea Hsp21, the Drosophila Hsp23 and the mouse Hsp25, were well expressed in tobacco protoplasts and formed homo-oligomers of 200-700 kDa, none of them could be recruited to HSG complexes.
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Affiliation(s)
- M Kirschner
- Department of Molecular Cell Biology, Biocenter N200, 3OG, Goethe University Frankfurt, Marie Curie Str. 9, D-60439 Frankfurt, Germany
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30
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Abstract
The elevated expression of stress proteins is considered to be a universal response to adverse conditions, representing a potential mechanism of cellular defense against disease and a potential target for novel therapeutics, including gene therapy and chaperone-modulating reagents. Recently, a single mutation in the small heat-shock protein human alphaB-crystallin was linked to desmin-related myopathy, which is characterized by abnormal intracellular aggregates of intermediate filaments in human muscle. New findings demonstrate that the high level of expression of stress proteins can contribute to an autoimmune response and can protect proteins that contribute to disease processes.
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Affiliation(s)
- J I Clark
- 357420 Biological Structure and Ophthalmology, University of Washington, Seattle, WA 98195-7420, USA.
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