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Lee J, Ryu B, Kim T, Kim KK. Cryo-EM structure of a 16.5-kDa small heat-shock protein from Methanocaldococcus jannaschii. Int J Biol Macromol 2024; 258:128763. [PMID: 38103675 DOI: 10.1016/j.ijbiomac.2023.128763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
The small heat-shock protein (sHSP) from the archaea Methanocaldococcus jannaschii, MjsHSP16.5, functions as a broad substrate ATP-independent holding chaperone protecting misfolded proteins from aggregation under stress conditions. This protein is the first sHSP characterized by X-ray crystallography, thereby contributing significantly to our understanding of sHSPs. However, despite numerous studies assessing its functions and structures, the precise arrangement of the N-terminal domains (NTDs) within this sHSP cage remains elusive. Here we present the cryo-electron microscopy (cryo-EM) structure of MjsHSP16.5 at 2.49-Å resolution. The subunits of MjsHSP16.5 in the cryo-EM structure exhibit lesser compaction compared to their counterparts in the crystal structure. This structural feature holds particular significance in relation to the biophysical properties of MjsHSP16.5, suggesting a close resemblance to this sHSP native state. Additionally, our cryo-EM structure unveils the density of residues 24-33 within the NTD of MjsHSP16.5, a feature that typically remains invisible in the majority of its crystal structures. Notably, these residues show a propensity to adopt a β-strand conformation and engage in antiparallel interactions with strand β1, both intra- and inter-subunit modes. These structural insights are corroborated by structural predictions, disulfide bond cross-linking studies of Cys-substitution mutants, and protein disaggregation assays. A comprehensive understanding of the structural features of MjsHSP16.5 expectedly holds the potential to inspire a wide range of interdisciplinary applications, owing to the renowned versatility of this sHSP as a nanoscale protein platform.
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Affiliation(s)
- Joohyun Lee
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Bumhan Ryu
- Research Solution Center, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea
| | - Truc Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.
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2
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Strauch A, Rossa B, Köhler F, Haeussler S, Mühlhofer M, Rührnößl F, Körösy C, Bushman Y, Conradt B, Haslbeck M, Weinkauf S, Buchner J. The permanently chaperone-active small heat shock protein Hsp17 from Caenorhabditis elegans exhibits topological separation of its N-terminal regions. J Biol Chem 2022; 299:102753. [PMID: 36442512 PMCID: PMC9800568 DOI: 10.1016/j.jbc.2022.102753] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022] Open
Abstract
Small Heat shock proteins (sHsps) are a family of molecular chaperones that bind nonnative proteins in an ATP-independent manner. Caenorhabditis elegans encodes 16 different sHsps, among them Hsp17, which is evolutionarily distinct from other sHsps in the nematode. The structure and mechanism of Hsp17 and how these may differ from other sHsps remain unclear. Here, we find that Hsp17 has a distinct expression pattern, structural organization, and chaperone function. Consistent with its presence under nonstress conditions, and in contrast to many other sHsps, we determined that Hsp17 is a mono-disperse, permanently active chaperone in vitro, which interacts with hundreds of different C. elegans proteins under physiological conditions. Additionally, our cryo-EM structure of Hsp17 reveals that in the 24-mer complex, 12 N-terminal regions are involved in its chaperone function. These flexible regions are located on the outside of the spherical oligomer, whereas the other 12 N-terminal regions are engaged in stabilizing interactions in its interior. This allows the same region in Hsp17 to perform different functions depending on the topological context. Taken together, our results reveal structural and functional features that further define the structural basis of permanently active sHsps.
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Affiliation(s)
- Annika Strauch
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Benjamin Rossa
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Fabian Köhler
- Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Simon Haeussler
- Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Moritz Mühlhofer
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Florian Rührnößl
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Caroline Körösy
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany; Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, Netherlands
| | - Yevheniia Bushman
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Barbara Conradt
- Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Martin Haslbeck
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Sevil Weinkauf
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Johannes Buchner
- Center for Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany.
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3
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Oligomeric Structural Transition of HspB1 from Chinese Hamster. Int J Mol Sci 2021; 22:ijms221910797. [PMID: 34639138 PMCID: PMC8509488 DOI: 10.3390/ijms221910797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 11/26/2022] Open
Abstract
HspB1 is a mammalian sHsp that is ubiquitously expressed in almost all tissues and involved in regulating many vital functions. Although the recent crystal structure of human HspB1 showed that 24 monomers form the oligomeric complex of human HspB1 in a spherical configuration, the molecular architecture of HspB1 is still controversial. In this study, we examined the oligomeric structural change of CgHspB1 by sedimentation velocity analytical ultracentrifugation. At the low temperature of 4 °C, CgHspB1 exists as an 18-mer, probably a trimeric complex of hexamers. It is relatively unstable and partially dissociates into small oligomers, hexamers, and dodecamers. At elevated temperatures, the 24-mer was more stable than the 18-mer. The 24-mer is also in dynamic equilibrium with the dissociated oligomers in the hexameric unit. The hexamer further dissociates to dimers. The disulfide bond between conserved cysteine residues seems to be partly responsible for the stabilization of hexamers. The N-terminal domain is involved in the assembly of dimers and the interaction between hexamers. It is plausible that CgHspB1 expresses a chaperone function in the 24-mer structure.
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4
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Cui F, Taier G, Wang X, Wang K. Genome-Wide Analysis of the HSP20 Gene Family and Expression Patterns of HSP20 Genes in Response to Abiotic Stresses in Cynodon transvaalensis. Front Genet 2021; 12:732812. [PMID: 34567082 PMCID: PMC8455957 DOI: 10.3389/fgene.2021.732812] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/10/2021] [Indexed: 11/13/2022] Open
Abstract
African bermudagrass (Cynodon transvaalensis Burtt-Davy) is an important warm-season turfgrass and forage grass species. Heat shock protein 20 (HSP20) is a diverse, ancient, and important protein family. To date, HSP20 genes have not been characterized genome-widely in African bermudagrass. Here, we confirmed 41 HSP20 genes in African bermudagrass genome. On the basis of the phylogenetic tree and cellular locations, the HSP20 proteins were classified into 12 subfamilies. Motif composition was consistent with the phylogeny. Moreover, we identified 15 pairs of paralogs containing nine pairs of tandem duplicates and six pairs of WGD/segmental duplicates of HSP20 genes. Unsurprisingly, the syntenic genes revealed that African bermudagrass had a closer evolutionary relationship with monocots (maize and rice) than dicots (Arabidopsis and soybean). The expression patterns of HSP20 genes were identified with the transcriptome data under abiotic stresses. According to the expression profiles, HSP20 genes could be clustered into three groups (Groups I, II, and III). Group I was the largest, and these genes were up-regulated in response to heat stress as expected. In Group II, one monocot-specific HSP20, CtHSP20-14 maintained higher expression levels under optimum temperature and low temperature, but not high temperature. Moreover, a pair of WGD/segmental duplicates CtHSP20-9 and CtHSP20-10 were among the most conserved HSP20s across different plant species, and they seemed to be positively selected in response to extreme temperatures during evolution. A total of 938 cis-elements were captured in the putative promoters of HSP20 genes. Almost half of the cis-elements were stress responsive, indicating that the expression pattern of HSP20 genes under abiotic stresses might be largely regulated by the cis-elements. Additionally, three-dimensional structure simulations and protein-protein interaction networks were incorporated to resolve the function mechanism of HSP20 proteins. In summary, the findings fulfilled the HSP20 family analysis and could provide useful information for further functional investigations of the specific HSP20s (e.g., CtHSP20-9, CtHSP20-10, and CtHSP20-14) in African bermudagrass.
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Affiliation(s)
- Fengchao Cui
- Department of Turfgrass Science and Engineering, College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Geli Taier
- Department of Turfgrass Science and Engineering, College of Grassland Science and Technology, China Agricultural University, Beijing, China
| | - Xiangfeng Wang
- National Maize Improvement Center, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Kehua Wang
- Department of Turfgrass Science and Engineering, College of Grassland Science and Technology, China Agricultural University, Beijing, China
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5
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Kurre D, Suguna K. Network of Entamoeba histolytica HSP18.5 dimers formed by two overlapping [IV]-X-[IV] motifs. Proteins 2021; 89:1039-1054. [PMID: 33792100 DOI: 10.1002/prot.26081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 02/19/2021] [Accepted: 03/22/2021] [Indexed: 11/11/2022]
Abstract
Small heat shock proteins (sHSPs) are ATP-independent molecular chaperones with low molecular weight that prevent the aggregation of proteins during stress conditions and maintain protein homeostasis in the cell. sHSPs exist in dynamic equilibrium as a mixture of oligomers of various sizes with a constant exchange of subunits between them. Many sHSPs form cage-like assemblies that may dissociate into smaller oligomers during stress conditions. We carried out the functional and structural characterization of a small heat shock protein, HSP18.5, from Entamoeba histolytica (EhHSP18.5). It showed a pH-dependent change in its oligomeric state, which varied from a tetramer to larger than 48-mer. EhHSP18.5 protected Nde I and lysozyme substrates from temperature and chemical stresses, respectively. The crystal structure of EhHSP18.5 was determined at a resolution of 3.28 Å in C2221 cell with four subunits in the asymmetric unit forming two non-metazoan sHSP-type dimers. Unlike the reported cage-like structures, EhHSP18.5 formed a network of linear chains of molecules in the crystal. Instead of a single [IV]-X-[IV] motif, EhHSP18.5 has two overlapping I/V-X-I/V sequences at the C-terminus giving rise to novel interactions between the dimers. Negative staining Electron Microscopy images of EhHSP18.5 showed the presence of multiple oligomers: closed structures of various sizes and long tube-like structures.
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Affiliation(s)
- Devanshu Kurre
- Molecular Biophysics unit, Indian Institute of Science, Bangalore, India
| | - Kaza Suguna
- Molecular Biophysics unit, Indian Institute of Science, Bangalore, India
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6
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Proteinaceous Transformers: Structural and Functional Variability of Human sHsps. Int J Mol Sci 2020; 21:ijms21155448. [PMID: 32751672 PMCID: PMC7432308 DOI: 10.3390/ijms21155448] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 02/04/2023] Open
Abstract
The proteostasis network allows organisms to support and regulate the life cycle of proteins. Especially regarding stress, molecular chaperones represent the main players within this network. Small heat shock proteins (sHsps) are a diverse family of ATP-independent molecular chaperones acting as the first line of defense in many stress situations. Thereby, the promiscuous interaction of sHsps with substrate proteins results in complexes from which the substrates can be refolded by ATP-dependent chaperones. Particularly in vertebrates, sHsps are linked to a broad variety of diseases and are needed to maintain the refractive index of the eye lens. A striking key characteristic of sHsps is their existence in ensembles of oligomers with varying numbers of subunits. The respective dynamics of these molecules allow the exchange of subunits and the formation of hetero-oligomers. Additionally, these dynamics are closely linked to the chaperone activity of sHsps. In current models a shift in the equilibrium of the sHsp ensemble allows regulation of the chaperone activity, whereby smaller oligomers are commonly the more active species. Different triggers reversibly change the oligomer equilibrium and regulate the activity of sHsps. However, a finite availability of high-resolution structures of sHsps still limits a detailed mechanistic understanding of their dynamics and the correlating recognition of substrate proteins. Here we summarize recent advances in understanding the structural and functional relationships of human sHsps with a focus on the eye-lens αA- and αB-crystallins.
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7
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Sha E, Nakamura M, Ankai K, Yamamoto YY, Oka T, Yohda M. Functional and structural characterization of HspB1/Hsp27 from Chinese hamster ovary cells. FEBS Open Bio 2019; 9:1826-1834. [PMID: 31441240 PMCID: PMC6768103 DOI: 10.1002/2211-5463.12726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 08/04/2019] [Accepted: 08/20/2019] [Indexed: 11/20/2022] Open
Abstract
Small heat shock proteins (sHsps) endow cells with stress tolerance. Of the various sHsps in mammals, HspB1, also known as Hsp27, is the most ubiquitous. To examine the structure and function of HspB1, we expressed, purified, and characterized HspB1 from Chinese hamster (Cricetulus griseus) ovary cells (CgHspB1). CgHspB1 forms a large oligomeric structure. We observed a monodisperse 16‐mer with an elongated sphere, but this is affected by changes in various conditions, including temperature. Under dilute conditions, CgHspB1 dissociates into small oligomers at elevated temperatures. The dissociated conformers interacted with the gel filtration column through hydrophobic interactions. In contrast, dissociation of the oligomer was not observed by small‐angle X‐ray scattering at 55 °C. The result partially coincides with the results of size exclusion chromatography, showing that dissociation did not occur at high protein concentrations. However, a significant structural change in the oligomeric conformations appears to occur between room and higher temperatures. Reflecting their status as homeotherms, mammalian sHsps are regulated by phosphorylation. A phosphorylation mimic mutant of CgHspB1 with the replacement of Ser15 to Asp exhibited relatively lower oligomer stability and greater protective ability against thermal aggregation than the wild‐type protein. The result clearly shows a correlation between oligomer dissociation and chaperone activity.
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Affiliation(s)
- Eiryo Sha
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Japan
| | - Manami Nakamura
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Japan
| | - Kazuya Ankai
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Japan
| | - Yohei Y Yamamoto
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Japan
| | - Toshihiko Oka
- Department of Physics, Faculty of Science, Shizuoka University, Japan
| | - Masafumi Yohda
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Japan
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8
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Elucidation of the molecular mechanism of heat shock proteins and its correlation with the effects of double mutations S679A & K722Q in the catalytic dyad residues of Lon protease. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2019.100438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Ghosh S, Salama F, Dines M, Lahav A, Adir N. Biophysical and structural characterization of the small heat shock protein HspA from Thermosynechococcus vulcanus in 2 M urea. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:442-452. [PMID: 30711645 DOI: 10.1016/j.bbapap.2018.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/29/2018] [Accepted: 12/11/2018] [Indexed: 10/27/2022]
Abstract
Small heat shock proteins (sHSPs) belong to the superfamily of molecular chaperones. They prevent aggregation of partially unfolded or misfolded client proteins, providing protection to organisms under stress conditions. Here, we report the biophysical and structural characterization of a small heat shock protein (HspA) from a thermophilic cyanobacterium Thermosynechococcus vulcanus in the presence of 2 M urea. HspA has been shown to be important for the protection of Photosystem II and the Phycobilisome antenna complex at elevated temperatures. Heterologously expressed HspA requires the presence of 1-2 M urea to maintain its solubility at concentrations required for most characterization methods. Spectroscopic studies reveal the presence of the β-sheet structure and intactness of the tertiary fold in HspA. In vitro assays show that the HspA maintains chaperone-like activity in protecting soluble proteins from thermal aggregation. Chromatography and electron microscopy show that the HspA exists as a mixture of oligomeric forms in the presence of 2 M urea. HspA was successfully crystallized only in the presence of 2 M urea. The crystal structure of HspA shows urea-induced loss of about 30% of the secondary structure without major alteration in the tertiary structure of the protein. The electron density maps reveal changes in the hydrogen bonding network which we attribute to the presence of urea. The crystal structure of HspA demonstrates a mixture of both direct interactions between urea and protein functionalities and interactions between urea and the surrounding solvent that indirectly affect the protein, which are in accordance with previously published studies.
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Affiliation(s)
- Sudeshna Ghosh
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Faris Salama
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Monica Dines
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Avital Lahav
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel.
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10
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Bhandari S, Biswas S, Chaudhary A, Dutta S, Suguna K. Dodecameric structure of a small heat shock protein from Mycobacterium marinum M. Proteins 2019; 87:365-379. [PMID: 30632633 DOI: 10.1002/prot.25657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 12/24/2018] [Accepted: 01/05/2019] [Indexed: 12/31/2022]
Abstract
Small heat shock proteins (sHSPs) are ATP-independent molecular chaperones present ubiquitously in all kingdoms of life. Their low molecular weight subunits associate to form higher order structures. Under conditions of stress, sHSPs prevent aggregation of substrate proteins by undergoing rapid changes in their conformation or stoichiometry. Polydispersity and dynamic nature of these proteins have made structural investigations through crystallography a daunting task. In pathogens like Mycobacteria, sHSPs are immuno-dominant antigens, enabling survival of the pathogen within the host and contributing to disease persistence. We characterized sHSPs from Mycobacterium marinum M and determined the crystal structure of one of these. The protein crystallized in three different conditions as dodecamers, with dimers arranged in a tetrahedral fashion to form a closed cage-like architecture. Interestingly, we found a pentapeptide bound to the dodecamers revealing one of the modes of sHSP-substrate interaction. Further, we have observed that ATP inhibits the chaperoning activity of the protein.
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Affiliation(s)
- Spraha Bhandari
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Sreeparna Biswas
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Anuradha Chaudhary
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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11
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Dahiya V, Buchner J. Functional principles and regulation of molecular chaperones. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 114:1-60. [PMID: 30635079 DOI: 10.1016/bs.apcsb.2018.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To be able to perform their biological function, a protein needs to be correctly folded into its three dimensional structure. The protein folding process is spontaneous and does not require the input of energy. However, in the crowded cellular environment where there is high risk of inter-molecular interactions that may lead to protein molecules sticking to each other, hence forming aggregates, protein folding is assisted. Cells have evolved robust machinery called molecular chaperones to deal with the protein folding problem and to maintain proteins in their functional state. Molecular chaperones promote efficient folding of newly synthesized proteins, prevent their aggregation and ensure protein homeostasis in cells. There are different classes of molecular chaperones functioning in a complex interplay. In this review, we discuss the principal characteristics of different classes of molecular chaperones, their structure-function relationships, their mode of regulation and their involvement in human disorders.
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Affiliation(s)
- Vinay Dahiya
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany.
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12
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Haslbeck M, Weinkauf S, Buchner J. Small heat shock proteins: Simplicity meets complexity. J Biol Chem 2018; 294:2121-2132. [PMID: 30385502 DOI: 10.1074/jbc.rev118.002809] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Small heat shock proteins (sHsps) are a ubiquitous and ancient family of ATP-independent molecular chaperones. A key characteristic of sHsps is that they exist in ensembles of iso-energetic oligomeric species differing in size. This property arises from a unique mode of assembly involving several parts of the subunits in a flexible manner. Current evidence suggests that smaller oligomers are more active chaperones. Thus, a shift in the equilibrium of the sHsp ensemble allows regulating the chaperone activity. Different mechanisms have been identified that reversibly change the oligomer equilibrium. The promiscuous interaction with non-native proteins generates complexes that can form aggregate-like structures from which native proteins are restored by ATP-dependent chaperones such as Hsp70 family members. In recent years, this basic paradigm has been expanded, and new roles and new cofactors, as well as variations in structure and regulation of sHsps, have emerged.
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Affiliation(s)
- Martin Haslbeck
- From the Department of Chemie and Center for Integrated Protein Science, Technische Universität München, Lichtenbergstrasse 4, 85 748 Garching, Germany
| | - Sevil Weinkauf
- From the Department of Chemie and Center for Integrated Protein Science, Technische Universität München, Lichtenbergstrasse 4, 85 748 Garching, Germany
| | - Johannes Buchner
- From the Department of Chemie and Center for Integrated Protein Science, Technische Universität München, Lichtenbergstrasse 4, 85 748 Garching, Germany
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13
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Santhanagopalan I, Degiacomi MT, Shepherd DA, Hochberg GKA, Benesch JLP, Vierling E. It takes a dimer to tango: Oligomeric small heat shock proteins dissociate to capture substrate. J Biol Chem 2018; 293:19511-19521. [PMID: 30348902 DOI: 10.1074/jbc.ra118.005421] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/12/2018] [Indexed: 12/23/2022] Open
Abstract
Small heat-shock proteins (sHsps) are ubiquitous molecular chaperones, and sHsp mutations or altered expression are linked to multiple human disease states. sHsp monomers assemble into large oligomers with dimeric substructure, and the dynamics of sHsp oligomers has led to major questions about the form that captures substrate, a critical aspect of their mechanism of action. We show here that substructural dimers of two plant dodecameric sHsps, Ta16.9 and homologous Ps18.1, are functional units in the initial encounter with unfolding substrate. We introduced inter-polypeptide disulfide bonds at the two dodecameric interfaces, dimeric and nondimeric, to restrict how their assemblies can dissociate. When disulfide-bonded at the nondimeric interface, mutants of Ta16.9 and Ps18.1 (TaCT-ACD and PsCT-ACD) were inactive but, when reduced, had WT-like chaperone activity, demonstrating that dissociation at nondimeric interfaces is essential for sHsp activity. Moreover, the size of the TaCT-ACD and PsCT-ACD covalent unit defined a new tetrahedral geometry for these sHsps, different from that observed in the Ta16.9 X-ray structure. Importantly, oxidized Tadimer (disulfide bonded at the dimeric interface) exhibited greatly enhanced ability to protect substrate, indicating that strengthening the dimeric interface increases chaperone efficiency. Temperature-induced size and secondary structure changes revealed that folded sHsp dimers interact with substrate and that dimer stability affects chaperone efficiency. These results yield a model in which sHsp dimers capture substrate before assembly into larger, heterogeneous sHsp-substrate complexes for substrate refolding or degradation, and suggest that tuning the strength of the dimer interface can be used to engineer sHsp chaperone efficiency.
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Affiliation(s)
- Indu Santhanagopalan
- From the Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Matteo T Degiacomi
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and.,Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | - Dale A Shepherd
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Georg K A Hochberg
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Elizabeth Vierling
- From the Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003,
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14
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Roy M, Gupta S, Patranabis S, Ghosh A. The oligomeric plasticity of Hsp20 of Sulfolobus acidocaldarius protects environment-induced protein aggregation and membrane destabilization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2549-2565. [PMID: 30293966 DOI: 10.1016/j.bbamem.2018.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/29/2018] [Accepted: 09/05/2018] [Indexed: 12/21/2022]
Abstract
Small heat shock proteins (sHsps) are a ubiquitous family of molecular chaperones that rescue misfolded proteins from irreversible aggregation during cellular stress. Many such sHsps exist as large polydisperse species in solution, and a rapid dynamic subunit exchange between oligomeric and dissociated forms modulates their function under a variety of stress conditions. Here, we investigated the structural and functional properties of Hsp20 from thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. To provide a framework for investigating the structure-function relationship of Hsp20 and understanding its dynamic nature, we employed several biophysical and biochemical techniques. Our data suggested the existence of a ~24-mer of Hsp20 at room temperature (25 °C) and a higher oligomeric form at higher temperature (50 °C-70 °C) and lower pH (3.0-5.0). To our surprise, we identified a dimeric form of protein as the functional conformation in the presence of aggregating substrate proteins. The hydrophobic microenvironment mainly regulates the oligomeric plasticity of Hsp20, and it plays a key role in the protection of stress-induced protein aggregation. In Sulfolobus sp., Hsp20, despite being a non-secreted protein, has been reported to be present in secretory vesicles and it is still unclear whether it stabilizes substrate proteins or membrane lipids within the secreted vesicles. To address such an issue, we tested the ability of Hsp20 to interact with membrane lipids along with its ability to modulate membrane fluidity. Our data revealed that Hsp20 interacts with membrane lipids via a hydrophobic interaction and it lowers the propensity of in vitro phase transition of bacterial and archaeal lipids.
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Affiliation(s)
- Mousam Roy
- Department of Biochemistry, Bose Institute, Centenary Campus, P 1/12, C. I. T. Road, Scheme - VIIM, Kolkata 700054, West Bengal, India
| | - Sayandeep Gupta
- Department of Biochemistry, Bose Institute, Centenary Campus, P 1/12, C. I. T. Road, Scheme - VIIM, Kolkata 700054, West Bengal, India
| | - Somi Patranabis
- Department of Biochemistry, Bose Institute, Centenary Campus, P 1/12, C. I. T. Road, Scheme - VIIM, Kolkata 700054, West Bengal, India
| | - Abhrajyoti Ghosh
- Department of Biochemistry, Bose Institute, Centenary Campus, P 1/12, C. I. T. Road, Scheme - VIIM, Kolkata 700054, West Bengal, India.
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15
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Jovcevski B, Andrew Aquilina J, Benesch JLP, Ecroyd H. The influence of the N-terminal region proximal to the core domain on the assembly and chaperone activity of αB-crystallin. Cell Stress Chaperones 2018; 23:827-836. [PMID: 29520626 PMCID: PMC6111084 DOI: 10.1007/s12192-018-0889-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/19/2018] [Accepted: 02/24/2018] [Indexed: 01/24/2023] Open
Abstract
αB-Crystallin (HSPB5) is a small heat-shock protein that is composed of dimers that then assemble into a polydisperse ensemble of oligomers. Oligomerisation is mediated by heterologous interactions between the C-terminal tail of one dimer and the core "α-crystallin" domain of another and stabilised by interactions made by the N-terminal region. Comparatively little is known about the latter contribution, but previous studies have suggested that residues in the region 54-60 form contacts that stabilise the assembly. We have generated mutations in this region (P58A, S59A, S59K, R56S/S59R and an inversion of residues 54-60) to examine their impact on oligomerisation and chaperone activity in vitro. By using native mass spectrometry, we found that all the αB-crystallin mutants were assembly competent, populating similar oligomeric distributions to wild-type, ranging from 16-mers to 30-mers. However, circular dichroism spectroscopy, intrinsic tryptophan and bis-ANS fluorescence studies demonstrated that the secondary structure differs to wild type, the 54-60 inversion mutation having the greatest impact. All the mutants exhibited a dramatic decrease in exposed hydrophobicity. We also found that the mutants in general were equally active as the wild-type protein in inhibiting the amorphous aggregation of insulin and seeded amyloid fibrillation of α-synuclein in vitro, except for the 54-60 inversion mutant, which was significantly less effective at inhibiting insulin aggregation. Our data indicate that alterations in the part of the N-terminal region proximal to the core domain do not drastically affect the oligomerisation of αB-crystallin, reinforcing the robustness of αB-crystallin in functioning as a molecular chaperone.
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Affiliation(s)
- Blagojce Jovcevski
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia
| | - J Andrew Aquilina
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia
| | - Justin L P Benesch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Heath Ecroyd
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia.
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16
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The Role of the Arginine in the Conserved N-Terminal Domain RLFDQxFG Motif of Human Small Heat Shock Proteins HspB1, HspB4, HspB5, HspB6, and HspB8. Int J Mol Sci 2018; 19:ijms19072112. [PMID: 30036999 PMCID: PMC6073470 DOI: 10.3390/ijms19072112] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 07/14/2018] [Accepted: 07/17/2018] [Indexed: 11/17/2022] Open
Abstract
Although the N-terminal domain of vertebrate small heat shock proteins (sHsp) is poorly conserved, it contains a core motif preserved in many members of the sHsp family. The role of this RLFDQxFG motif remains elusive. We analyzed the specific role of the first arginine residue of this conserved octet sequence in five human sHsps (HspB1, HspB4, HspB5, HspB6, and HspB8). Substitution of this arginine with an alanine induced changes in thermal stability and/or intrinsic fluorescence of the related HspB1 and HspB8, but yielded only modest changes in the same biophysical properties of HspB4, HspB5, and HspB6 which together belong to another clade of vertebrate sHsps. Removal of the positively charged Arg side chain resulted in destabilization of the large oligomers of HspB1 and formation of smaller size oligomers of HspB5. The mutation induced only minor changes in the structure of HspB4 and HspB6. In contrast, the mutation in HspB8 was accompanied by shifting the equilibrium from dimers towards the formation of larger oligomers. We conclude that the RLFDQxFG motif plays distinct roles in the structure of several sHsp orthologs. This role correlates with the evolutionary relationship of the respective sHsps, but ultimately, it reflects the sequence context of this motif.
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17
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Li Y, Xu X, Qu R, Zhang G, Rajoka MSR, Shao D, Jiang C, Shi J. Heterologous expression of Oenococcus oeni sHSP20 confers temperature stress tolerance in Escherichia coli. Cell Stress Chaperones 2018; 23:653-662. [PMID: 29359265 PMCID: PMC6045537 DOI: 10.1007/s12192-018-0874-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/19/2017] [Accepted: 01/03/2018] [Indexed: 12/11/2022] Open
Abstract
Small heat shock proteins (sHSPs) are heat shock proteins sized 12-43 kDa that can protect proteins from denaturation, particularly under high temperature; sHSPs thus increase the heat tolerance capability of an organisms enabling survival in adverse climates. sHSP20 is overexpressed in Oenococcus oeni in response to low temperatures. However, we found that overexpression of sHSP20 in Escherichia coli BL21 increased the microbial survival ratio at 50 °C by almost 2 h. Adding sHSP20 to the glutamate dehydrogenase solution significantly increased the stability of the enzyme at high temperature (especially at 60-70 °C), low pH values (especially below 6.0), and high concentration of metal ions of Ga2+, Zn2+, Mn2+, and Fe3+. Notably, the coexpression of sHSP20 significantly enhanced soluble expression of laccase from Phomopsis sp. XP-8 (CCTCCM209291) in E. coli without codon optimization, as well as the activity and heat stability of the expressed enzyme. In addition to the chaperone activity of sHSP20 in the gene containing host in vivo and the enzyme heat stability in vitro, our study indicated the capability of coexpression of sHSP20 to increase the efficiency of prokaryotic expression of fungal genes and the activity of expressed enzymes. Graphical abstract ᅟ.
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Affiliation(s)
- Yan Li
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Xiaoguang Xu
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Rui Qu
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Guoqiang Zhang
- College of Food Science, Agricultural and Animal Husbandry College of Tibet University, Linzhi, 860000 Xi Zang People’s Republic of China
| | - Muhammad Shahid Riaz Rajoka
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Dongyan Shao
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Chunmei Jiang
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
| | - Junling Shi
- Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi’an, 710072 Shaanxi People’s Republic of China
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18
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Terminal Regions Confer Plasticity to the Tetrameric Assembly of Human HspB2 and HspB3. J Mol Biol 2018; 430:3297-3310. [PMID: 29969581 PMCID: PMC6119766 DOI: 10.1016/j.jmb.2018.06.047] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 01/17/2023]
Abstract
Heterogeneity in small heat shock proteins (sHsps) spans multiple spatiotemporal regimes-from fast fluctuations of part of the protein, to conformational variability of tertiary structure, plasticity of the interfaces, and polydispersity of the inter-converting, and co-assembling oligomers. This heterogeneity and dynamic nature of sHsps has significantly hindered their structural characterization. Atomic coordinates are particularly lacking for vertebrate sHsps, where most available structures are of extensively truncated homomers. sHsps play important roles in maintaining protein levels in the cell and therefore in organismal health and disease. HspB2 and HspB3 are vertebrate sHsps that are found co-assembled in neuromuscular cells, and variants thereof are associated with disease. Here, we present the structure of human HspB2/B3, which crystallized as a hetero-tetramer in a 3:1 ratio. In the HspB2/B3 tetramer, the four α-crystallin domains (ACDs) assemble into a flattened tetrahedron which is pierced by two non-intersecting approximate dyads. Assembly is mediated by flexible "nuts and bolts" involving IXI/V motifs from terminal regions filling ACD pockets. Parts of the N-terminal region bind in an unfolded conformation into the anti-parallel shared ACD dimer grooves. Tracts of the terminal regions are not resolved, most likely due to their disorder in the crystal lattice. This first structure of a full-length human sHsp heteromer reveals the heterogeneous interactions of the terminal regions and suggests a plasticity that is important for the cytoprotective functions of sHsps.
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19
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Bhattacharjee S, Dasgupta R, Bagchi A. Elucidation of the molecular mechanism of heat shock proteins and its correlation with K722Q mutations in Lon protease. Biosystems 2017; 159:12-22. [PMID: 28676239 DOI: 10.1016/j.biosystems.2017.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/22/2017] [Accepted: 06/22/2017] [Indexed: 10/19/2022]
Abstract
Cells withstand the effects of temperature change with the help of small heat shock proteins IbpA and IbpB. The IbpAB protein complex interacts with Lon protease in their free form and gets degraded at physiological temperature when there is no temperature stress. However, the proteolytic degradation of IbpAB is diminished when Lon is mutated. The mutation K722Q in Lon brings about some structural changes so that the proteolytic interactions between the heat shock proteins with that of the mutated Lon protease are lost. However, the detailed molecular aspects of the interactions are not yet fully understood. In the present, we made an attempt to analyze the biochemical aspects of the interactions between the small heat shock proteins IbpAB with wild type and mutant Lon protease. We for the first time deciphered the molecular details of the mechanism of interaction of small heat shock proteins with Lon protease bearing K722Q mutation i.e. the interaction pattern of heat shock proteins with mutant Lon protease at physiological temperature in absence of proteolytic machinery. Our study may therefore be useful to elucidate the mechanistic details of the correlation with IbpA, IbpB and Lon protease.
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Affiliation(s)
- Sanchari Bhattacharjee
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, India.
| | - Rakhi Dasgupta
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, India.
| | - Angshuman Bagchi
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, India.
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20
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Moutaoufik MT, Morrow G, Finet S, Tanguay RM. Effect of N-terminal region of nuclear Drosophila melanogaster small heat shock protein DmHsp27 on function and quaternary structure. PLoS One 2017; 12:e0177821. [PMID: 28520783 PMCID: PMC5433770 DOI: 10.1371/journal.pone.0177821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/03/2017] [Indexed: 01/12/2023] Open
Abstract
The importance of the N-terminal region (NTR) in the oligomerization and chaperone-like activity of the Drosophila melanogaster small nuclear heat shock protein DmHsp27 was investigated by mutagenesis using size exclusion chromatography and native gel electrophoresis. Mutation of two sites of phosphorylation in the N-terminal region, S58 and S75, did not affect the oligomerization equilibrium or the intracellular localization of DmHsp27 when transfected into mammalian cells. Deletion or mutation of specific residues within the NTR region delineated a motif (FGFG) important for the oligomeric structure and chaperone-like activity of this sHsp. While deletion of the full N-terminal region, resulted in total loss of chaperone-like activity, removal of the (FGFG) at position 29 to 32 or single mutation of F29A/Y, G30R and G32R enhanced oligomerization and chaperoning capacity under non-heat shock conditions in the insulin assay suggesting the importance of this site for chaperone activity. Unlike mammalian sHsps DmHsp27 heat activation leads to enhanced association of oligomers to form large structures of approximately 1100 kDa. A new mechanism of thermal activation for DmHsp27 is presented.
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Affiliation(s)
- Mohamed Taha Moutaoufik
- Laboratoire de génétique cellulaire et développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de biologie intégrative et des systèmes (IBIS) and PROTEO, Université Laval, Québec, Canada
| | - Geneviève Morrow
- Laboratoire de génétique cellulaire et développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de biologie intégrative et des systèmes (IBIS) and PROTEO, Université Laval, Québec, Canada
| | - Stéphanie Finet
- IMPMC UMR7590, CNRS, UPMC Paris 6, 4 place Jussieu, Paris, France
| | - Robert M. Tanguay
- Laboratoire de génétique cellulaire et développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de biologie intégrative et des systèmes (IBIS) and PROTEO, Université Laval, Québec, Canada
- * E-mail:
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21
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Heirbaut M, Lermyte F, Martin EM, Beelen S, Sobott F, Strelkov SV, Weeks SD. Specific sequences in the N-terminal domain of human small heat-shock protein HSPB6 dictate preferential hetero-oligomerization with the orthologue HSPB1. J Biol Chem 2017; 292:9944-9957. [PMID: 28487364 DOI: 10.1074/jbc.m116.773515] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 04/20/2017] [Indexed: 12/17/2022] Open
Abstract
Small heat-shock proteins (sHSPs) are a conserved group of molecular chaperones with important roles in cellular proteostasis. Although sHSPs are characterized by their small monomeric weight, they typically assemble into large polydisperse oligomers that vary in both size and shape but are principally composed of dimeric building blocks. These assemblies can include different sHSP orthologues, creating additional complexity that may affect chaperone activity. However, the structural and functional properties of such hetero-oligomers are poorly understood. We became interested in hetero-oligomer formation between human heat-shock protein family B (small) member 1 (HSPB1) and HSPB6, which are both highly expressed in skeletal muscle. When mixed in vitro, these two sHSPs form a polydisperse oligomer array composed solely of heterodimers, suggesting preferential association that is determined at the monomer level. Previously, we have shown that the sHSP N-terminal domains (NTDs), which have a high degree of intrinsic disorder, are essential for the biased formation. Here we employed iterative deletion mapping to elucidate how the NTD of HSPB6 influences its preferential association with HSPB1 and show that this region has multiple roles in this process. First, the highly conserved motif RLFDQXFG is necessary for subunit exchange among oligomers. Second, a site ∼20 residues downstream of this motif determines the size of the resultant hetero-oligomers. Third, a region unique to HSPB6 dictates the preferential formation of heterodimers. In conclusion, the disordered NTD of HSPB6 helps regulate the size and stability of hetero-oligomeric complexes, indicating that terminal sHSP regions define the assembly properties of these proteins.
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Affiliation(s)
- Michelle Heirbaut
- From the Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Frederik Lermyte
- the Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium, and
| | - Esther M Martin
- the Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium, and.,the Astbury Centre for Structural Molecular Biology and
| | - Steven Beelen
- From the Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Frank Sobott
- the Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium, and.,the Astbury Centre for Structural Molecular Biology and.,School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, United Kingdom
| | - Sergei V Strelkov
- From the Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium,
| | - Stephen D Weeks
- From the Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium,
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22
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Fonseca EMB, Scorsato V, Dos Santos ML, Júnior AT, Tada SFS, Dos Santos CA, de Toledo MAS, de Souza AP, Polikarpov I, Aparicio R. Crystal structure of a small heat-shock protein from Xylella fastidiosa reveals a distinct high-order structure. Acta Crystallogr F Struct Biol Commun 2017; 73:222-227. [PMID: 28368281 PMCID: PMC5379172 DOI: 10.1107/s2053230x17004101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 03/14/2017] [Indexed: 11/10/2022] Open
Abstract
Citrus variegated chlorosis is a disease that attacks economically important citrus plantations and is caused by the plant-pathogenic bacterium Xylella fastidiosa. In this work, the structure of a small heat-shock protein from X. fastidiosa (XfsHSP17.9) is reported. The high-order structures of small heat-shock proteins from other organisms are arranged in the forms of double-disc, hollow-sphere or spherical assemblies. Unexpectedly, the structure reported here reveals a high-order architecture forming a nearly square cavity.
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Affiliation(s)
- Emanuella Maria Barreto Fonseca
- Laboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, CP6154, 13083-970 Campinas-SP, Brazil
| | - Valéria Scorsato
- Laboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, CP6154, 13083-970 Campinas-SP, Brazil
| | - Marcelo Leite Dos Santos
- Laboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, CP6154, 13083-970 Campinas-SP, Brazil
| | - Atilio Tomazini Júnior
- Molecular Biotechnology Group, Department of Physics and Interdisciplinary Science, Sao Carlos Institute of Physics (IFSC), University of Sao Paulo (USP), Avenida Trabalhador São-carlense 400, Parque Arnold Schimidt, 13566-590 São Carlos-SP, Brazil
| | - Susely Ferraz Siqueira Tada
- Laboratory of Molecular and Genetic Analysis, Center for Molecular Biology and Genetic Engineering, Institute of Biology, University of Campinas, CP6010, 13083-875 Campinas-SP, Brazil
| | - Clelton Aparecido Dos Santos
- Laboratory of Molecular and Genetic Analysis, Center for Molecular Biology and Genetic Engineering, Institute of Biology, University of Campinas, CP6010, 13083-875 Campinas-SP, Brazil
| | - Marcelo Augusto Szymanski de Toledo
- Laboratory of Molecular and Genetic Analysis, Center for Molecular Biology and Genetic Engineering, Institute of Biology, University of Campinas, CP6010, 13083-875 Campinas-SP, Brazil
| | - Anete Pereira de Souza
- Laboratory of Molecular and Genetic Analysis, Center for Molecular Biology and Genetic Engineering, Institute of Biology, University of Campinas, CP6010, 13083-875 Campinas-SP, Brazil
| | - Igor Polikarpov
- Molecular Biotechnology Group, Department of Physics and Interdisciplinary Science, Sao Carlos Institute of Physics (IFSC), University of Sao Paulo (USP), Avenida Trabalhador São-carlense 400, Parque Arnold Schimidt, 13566-590 São Carlos-SP, Brazil
| | - Ricardo Aparicio
- Laboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, CP6154, 13083-970 Campinas-SP, Brazil
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23
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Rutsdottir G, Härmark J, Weide Y, Hebert H, Rasmussen MI, Wernersson S, Respondek M, Akke M, Højrup P, Koeck PJB, Söderberg CAG, Emanuelsson C. Structural model of dodecameric heat-shock protein Hsp21: Flexible N-terminal arms interact with client proteins while C-terminal tails maintain the dodecamer and chaperone activity. J Biol Chem 2017; 292:8103-8121. [PMID: 28325834 PMCID: PMC5427286 DOI: 10.1074/jbc.m116.766816] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/16/2017] [Indexed: 01/14/2023] Open
Abstract
Small heat-shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently, there is only one high-resolution structure of a plant sHsp published, that of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminal arms than Hsp16.9, with a functionally important and conserved methionine-rich motif. To provide a framework for investigating structure-function relationships of Hsp21 and understanding these sequence variations, we developed a structural model of Hsp21 based on homology modeling, cryo-EM, cross-linking mass spectrometry, NMR, and small-angle X-ray scattering. Our data suggest a dodecameric arrangement of two trimer-of-dimer discs stabilized by the C-terminal tails, possibly through tail-to-tail interactions between the discs, mediated through extended IXVXI motifs. Our model further suggests that six N-terminal arms are located on the outside of the dodecamer, accessible for interaction with client proteins, and distinct from previous undefined or inwardly facing arms. To test the importance of the IXVXI motif, we created the point mutant V181A, which, as expected, disrupts the Hsp21 dodecamer and decreases chaperone activity. Finally, our data emphasize that sHsp chaperone efficiency depends on oligomerization and that client interactions can occur both with and without oligomer dissociation. These results provide a generalizable workflow to explore sHsps, expand our understanding of sHsp structural motifs, and provide a testable Hsp21 structure model to inform future investigations.
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Affiliation(s)
| | - Johan Härmark
- the School of Technology and Health, KTH/Royal Institute of Technology and Department of Biosciences and Nutrition, Karolinska Institutet, SE-171 77 Stockholm, Sweden, and
| | - Yoran Weide
- From the Departments of Biochemistry and Structural Biology and
| | - Hans Hebert
- the School of Technology and Health, KTH/Royal Institute of Technology and Department of Biosciences and Nutrition, Karolinska Institutet, SE-171 77 Stockholm, Sweden, and
| | - Morten I Rasmussen
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | | | | | | | - Peter Højrup
- the Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Philip J B Koeck
- the School of Technology and Health, KTH/Royal Institute of Technology and Department of Biosciences and Nutrition, Karolinska Institutet, SE-171 77 Stockholm, Sweden, and
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24
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Sluchanko NN, Beelen S, Kulikova AA, Weeks SD, Antson AA, Gusev NB, Strelkov SV. Structural Basis for the Interaction of a Human Small Heat Shock Protein with the 14-3-3 Universal Signaling Regulator. Structure 2017; 25:305-316. [PMID: 28089448 PMCID: PMC5321513 DOI: 10.1016/j.str.2016.12.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/14/2016] [Accepted: 12/12/2016] [Indexed: 12/31/2022]
Abstract
By interacting with hundreds of protein partners, 14-3-3 proteins coordinate vital cellular processes. Phosphorylation of the small heat shock protein, HSPB6, within its intrinsically disordered N-terminal domain activates its interaction with 14-3-3, ultimately triggering smooth muscle relaxation. After analyzing the binding of an HSPB6-derived phosphopeptide to 14-3-3 using isothermal calorimetry and X-ray crystallography, we have determined the crystal structure of the complete assembly consisting of the 14-3-3 dimer and full-length HSPB6 dimer and further characterized this complex in solution using fluorescence spectroscopy, small-angle X-ray scattering, and limited proteolysis. We show that selected intrinsically disordered regions of HSPB6 are transformed into well-defined conformations upon the interaction, whereby an unexpectedly asymmetric structure is formed. This structure provides the first atomic resolution snapshot of a human small HSP in functional state, explains how 14-3-3 proteins sequester their regulatory partners, and can inform the design of small-molecule interaction modifiers to be used as myorelaxants.
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Affiliation(s)
- Nikolai N Sluchanko
- Laboratory of Structural Biochemistry of Proteins, A.N. Bach Institute of Biochemistry, Federal Research Center "Fundamentals of Biotechnology", Russian Academy of Sciences, 119071 Moscow, Russia.
| | - Steven Beelen
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Alexandra A Kulikova
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, 119991 Moscow, Russia
| | - Stephen D Weeks
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Alfred A Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, UK
| | - Nikolai B Gusev
- Department of Biochemistry, School of Biology, Moscow State University, 119991 Moscow, Russia
| | - Sergei V Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium.
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The function of small heat-shock proteins and their implication in proteostasis. Essays Biochem 2016; 60:163-172. [DOI: 10.1042/ebc20160010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/15/2016] [Indexed: 11/17/2022]
Abstract
All organisms rely on a conserved cellular machinery supporting and controlling the life cycle of proteins: the proteostasis network. Within this network, the main players that determine the fate of proteins are molecular chaperones, the ubiquitin–proteasome and the lysosome–autophagy systems. sHsps (small heat-shock proteins) represent one family of molecular chaperones found in all domains of life. They prevent irreversible aggregation of unfolded proteins and maintain proteostasis by stabilizing promiscuously a variety of non-native proteins in an ATP-independent manner. In the cellular chaperone network, sHsps act as the first line of defence and keep their substrates in a folding-competent state until they are refolded by downstream ATP-dependent chaperone systems. Besides this interaction with unfolding substrates upon stress, sHsps show a different mode of binding for specific clients which are also recognized under physiological conditions. In vertebrates, sHsps are especially needed to maintain the refractive index of the eye lens. Additionally, sHsps are linked to a broad variety of diseases such as myopathies and neuropathies. The most striking feature of sHsps is their ability to form dynamic ensembles of higher oligomers. The activity of sHsps is regulated by changes in the composition of the ensembles.
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Khalid R, Afzal M, Khurshid S, Paracha RZ, Khan IH, Akhtar MW. Fusion Molecules of Heat Shock Protein HSPX with Other Antigens of Mycobacterium tuberculosis Show High Potential in Serodiagnosis of Tuberculosis. PLoS One 2016; 11:e0163349. [PMID: 27654048 PMCID: PMC5031420 DOI: 10.1371/journal.pone.0163349] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 09/07/2016] [Indexed: 12/02/2022] Open
Abstract
Variable individual response against the antigens of Mycobacterium tuberculosis necessitates detection of multiple antibodies for enhancing reliability of serodiagnosis of tuberculosis. Fusion molecules consisting of two or more antigens showing high sensitivity would be helpful in achieving this objective. Antigens of M. tuberculosis HSPX and PE35 were expressed in a soluble form whereas tnPstS1 and FbpC1 were expressed as inclusion bodies at 37°C. Heat shock protein HSPX when attached to the N-termini of the antigens PE35, tnPstS1 and FbpC1, all the fusion molecules were expressed at high levels in E. coli in a soluble form. ELISA analysis of the plasma samples of TB patients against HSPX-tnPstS1 showed 57.7% sensitivity which is nearly the same as the expected combined value obtained after deducting the number of plasma samples (32) containing the antibodies against both the individual antigens. Likewise, the 54.4% sensitivity of HSPX-PE35 was nearly the same as that expected from the combined values of the contributing antigens. Structural analysis of all the fusion molecules by CD spectroscopy showed that α-helical and β-sheet contents were found close to those obtained through molecular modeling. Molecular modeling studies of HSPX-tnPstS1 and HSPX-PE35 support the analytical results as most of the epitopes of the contributing antigens were found to be available for binding to the corresponding antibodies. Using these fusion molecules in combination with other antigenic molecules should reduce the number of antigenic proteins required for a more reliable and economical serodiagnosis of tuberculosis. Also, HSPX seems to have potential application in soluble expression of heterologous proteins in E. coli.
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Affiliation(s)
- Ruqyya Khalid
- School of Biological Sciences, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
| | - Madeeha Afzal
- School of Biological Sciences, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
| | - Sana Khurshid
- School of Biological Sciences, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
| | - Rehan Zafar Paracha
- Atta-ur-Rehman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Imran H. Khan
- Department of Pathology and Laboratory Medicine, University of California, Davis, California, United States of America
| | - Muhammad Waheed Akhtar
- School of Biological Sciences, Quaid-e-Azam Campus, University of the Punjab, Lahore, Pakistan
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Fernández-Fernández MR, Sot B, Valpuesta JM. Molecular chaperones: functional mechanisms and nanotechnological applications. NANOTECHNOLOGY 2016; 27:324004. [PMID: 27363314 DOI: 10.1088/0957-4484/27/32/324004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Molecular chaperones are a group of proteins that assist in protein homeostasis. They not only prevent protein misfolding and aggregation, but also target misfolded proteins for degradation. Despite differences in structure, all types of chaperones share a common general feature, a surface that recognizes and interacts with the misfolded protein. This and other, more specialized properties can be adapted for various nanotechnological purposes, by modification of the original biomolecules or by de novo design based on artificial structures.
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Affiliation(s)
- M Rosario Fernández-Fernández
- Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus de la Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
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Mani N, Bhandari S, Moreno R, Hu L, Prasad BVV, Suguna K. Multiple oligomeric structures of a bacterial small heat shock protein. Sci Rep 2016; 6:24019. [PMID: 27053150 PMCID: PMC4823740 DOI: 10.1038/srep24019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 03/14/2016] [Indexed: 11/23/2022] Open
Abstract
Small heat shock proteins are ubiquitous molecular chaperones that form the first line of defence against the detrimental effects of cellular stress. Under conditions of stress they undergo drastic conformational rearrangements in order to bind to misfolded substrate proteins and prevent cellular protein aggregation. Owing to the dynamic nature of small heat shock protein oligomers, elucidating the structural basis of chaperone action and oligomerization still remains a challenge. In order to understand the organization of sHSP oligomers, we have determined crystal structures of a small heat shock protein from Salmonella typhimurium in a dimeric form and two higher oligomeric forms: an 18-mer and a 24-mer. Though the core dimer structure is conserved in all the forms, structural heterogeneity arises due to variation in the terminal regions.
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Affiliation(s)
- Nandini Mani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Spraha Bhandari
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rodolfo Moreno
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - B V Venkataram Prasad
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, United States
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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29
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Small Heat Shock Proteins, a Key Player in Grass Plant Thermotolerance. HEAT SHOCK PROTEINS AND PLANTS 2016. [DOI: 10.1007/978-3-319-46340-7_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Liu L, Chen JY, Yang B, Wang FH, Wang YH, Yun CH. Active-State Structures of a Small Heat-Shock Protein Revealed a Molecular Switch for Chaperone Function. Structure 2015; 23:2066-75. [PMID: 26439766 DOI: 10.1016/j.str.2015.08.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 08/27/2015] [Accepted: 08/29/2015] [Indexed: 01/09/2023]
Abstract
Small heat-shock proteins (sHsps) maintain cellular homeostasis by binding to denatured client proteins to prevent aggregation. Numerous studies indicate that the N-terminal domain (NTD) of sHsps is responsible for binding to client proteins, but the binding mechanism and chaperone activity regulation remain elusive. Here, we report the crystal structures of the wild-type and mutants of an sHsp from Sulfolobus solfataricus representing the inactive and active state of this protein, respectively. All three structures reveal well-defined NTD, but their conformations are remarkably different. The mutant NTDs show disrupted helices presenting a reformed hydrophobic surface compatible with recognizing client proteins. Our functional data show that mutating key hydrophobic residues in this region drastically altered the chaperone activity of this sHsp. These data suggest a new model in which a molecular switch located in NTD facilitates conformational changes for client protein binding.
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Affiliation(s)
- Liang Liu
- Institute of Systems Biomedicine, Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology and Center for Molecular and Translational Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, P.R. China; School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, P.R. China; Co-first author
| | - Ji-Yun Chen
- Institute of Systems Biomedicine, Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology and Center for Molecular and Translational Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, P.R. China; Co-first author
| | - Bo Yang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, P.R. China
| | - Fang-Hua Wang
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, P.R. China
| | - Yong-Hua Wang
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, P.R. China.
| | - Cai-Hong Yun
- Institute of Systems Biomedicine, Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology and Center for Molecular and Translational Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, P.R. China.
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31
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Han J, Kim K, Lee S. Screening Molecular Chaperones Similar to Small Heat Shock Proteins in Schizosaccharomyces pombe. MYCOBIOLOGY 2015; 43:272-279. [PMID: 26539043 PMCID: PMC4630433 DOI: 10.5941/myco.2015.43.3.272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 08/23/2015] [Accepted: 09/21/2015] [Indexed: 06/05/2023]
Abstract
To screen molecular chaperones similar to small heat shock proteins (sHsps), but without α-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an α-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at 70℃ for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no α-crystalline domain in their sequences.
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Affiliation(s)
- Jiyoung Han
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea
| | - Kanghwa Kim
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea
| | - Songmi Lee
- Department of Food and Nutrition, Dongshin University, Naju 58245, Korea
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Haslbeck M, Peschek J, Buchner J, Weinkauf S. Structure and function of α-crystallins: Traversing from in vitro to in vivo. Biochim Biophys Acta Gen Subj 2015; 1860:149-66. [PMID: 26116912 DOI: 10.1016/j.bbagen.2015.06.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/10/2015] [Accepted: 06/22/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND The two α-crystallins (αA- and αB-crystallin) are major components of our eye lenses. Their key function there is to preserve lens transparency which is a challenging task as the protein turnover in the lens is low necessitating the stability and longevity of the constituent proteins. α-Crystallins are members of the small heat shock protein family. αB-crystallin is also expressed in other cell types. SCOPE OF THE REVIEW The review summarizes the current concepts on the polydisperse structure of the α-crystallin oligomer and its chaperone function with a focus on the inherent complexity and highlighting gaps between in vitro and in vivo studies. MAJOR CONCLUSIONS Both α-crystallins protect proteins from irreversible aggregation in a promiscuous manner. In maintaining eye lens transparency, they reduce the formation of light scattering particles and balance the interactions between lens crystallins. Important for these functions is their structural dynamics and heterogeneity as well as the regulation of these processes which we are beginning to understand. However, currently, it still remains elusive to which extent the in vitro observed properties of α-crystallins reflect the highly crowded situation in the lens. GENERAL SIGNIFICANCE Since α-crystallins play an important role in preventing cataract in the eye lens and in the development of diverse diseases, understanding their mechanism and substrate spectra is of importance. To bridge the gap between the concepts established in vitro and the in vivo function of α-crystallins, the joining of forces between different scientific disciplines and the combination of diverse techniques in hybrid approaches are necessary. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Martin Haslbeck
- Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany
| | - Jirka Peschek
- Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.
| | - Sevil Weinkauf
- Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany.
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Fleckenstein T, Kastenmüller A, Stein ML, Peters C, Daake M, Krause M, Weinfurtner D, Haslbeck M, Weinkauf S, Groll M, Buchner J. The Chaperone Activity of the Developmental Small Heat Shock Protein Sip1 Is Regulated by pH-Dependent Conformational Changes. Mol Cell 2015; 58:1067-78. [PMID: 26009280 DOI: 10.1016/j.molcel.2015.04.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 02/24/2015] [Accepted: 04/14/2015] [Indexed: 01/25/2023]
Abstract
Small heat shock proteins (sHsps) are ubiquitous molecular chaperones that prevent the aggregation of unfolding proteins during proteotoxic stress. In Caenorhabditis elegans, Sip1 is the only sHsp exclusively expressed in oocytes and embryos. Here, we demonstrate that Sip1 is essential for heat shock survival of reproducing adults and embryos. X-ray crystallography and electron microscopy revealed that Sip1 exists in a range of well-defined globular assemblies consisting of two half-spheres, each made of dimeric "spokes." Strikingly, the oligomeric distribution of Sip1 as well as its chaperone activity depend on pH, with a trend toward smaller species and higher activity at acidic conditions such as present in nematode eggs. The analysis of the interactome shows that Sip1 has a specific substrate spectrum including proteins that are essential for embryo development.
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Affiliation(s)
- Tilly Fleckenstein
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Andreas Kastenmüller
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Martin Lorenz Stein
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Carsten Peters
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Marina Daake
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Maike Krause
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Daniel Weinfurtner
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Martin Haslbeck
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Sevil Weinkauf
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
| | - Michael Groll
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
| | - Johannes Buchner
- Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
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Oligomer-dependent and -independent chaperone activity of sHsps in different stressed conditions. FEBS Open Bio 2015; 5:155-62. [PMID: 25834780 PMCID: PMC4359974 DOI: 10.1016/j.fob.2015.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/20/2015] [Accepted: 02/28/2015] [Indexed: 12/12/2022] Open
Abstract
A great number of studies have proven that sHsps protect cells by inhibiting protein aggregation under heat stress, while little is known about their function to protect cells under acid stress. In this work, we show that Hsp20.1 and Hsp14.1 oligomers dissociated to smaller oligomeric species or even dimer/monomer at low pH (pH 4.0 and pH 2.0), whereas no prominent quaternary structural changes were seen at 50 °C. Both oligomers and smaller oligomeric species exhibited abilities to suppress client aggregation at low pH and at 50 °C. These results suggest that sHsps may function in different modes in different stressed conditions.
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35
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Haslbeck M, Vierling E. A first line of stress defense: small heat shock proteins and their function in protein homeostasis. J Mol Biol 2015; 427:1537-48. [PMID: 25681016 DOI: 10.1016/j.jmb.2015.02.002] [Citation(s) in RCA: 380] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
Small heat shock proteins (sHsps) are virtually ubiquitous molecular chaperones that can prevent the irreversible aggregation of denaturing proteins. sHsps complex with a variety of non-native proteins in an ATP-independent manner and, in the context of the stress response, form a first line of defense against protein aggregation in order to maintain protein homeostasis. In vertebrates, they act to maintain the clarity of the eye lens, and in humans, sHsp mutations are linked to myopathies and neuropathies. Although found in all domains of life, sHsps are quite diverse and have evolved independently in metazoans, plants and fungi. sHsp monomers range in size from approximately 12 to 42kDa and are defined by a conserved β-sandwich α-crystallin domain, flanked by variable N- and C-terminal sequences. Most sHsps form large oligomeric ensembles with a broad distribution of different, sphere- or barrel-like oligomers, with the size and structure of the oligomers dictated by features of the N- and C-termini. The activity of sHsps is regulated by mechanisms that change the equilibrium distribution in tertiary features and/or quaternary structure of the sHsp ensembles. Cooperation and/or co-assembly between different sHsps in the same cellular compartment add an underexplored level of complexity to sHsp structure and function.
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Affiliation(s)
- Martin Haslbeck
- Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85 748 Garching, Germany.
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Life Science Laboratories, N329 240 Thatcher Road, Amherst, MA 01003-9364, USA.
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37
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38
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Everything but the ACD, Functional Conservation of the Non-conserved Terminal Regions in sHSPs. HEAT SHOCK PROTEINS 2015. [DOI: 10.1007/978-3-319-16077-1_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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39
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Heirbaut M, Beelen S, Strelkov SV, Weeks SD. Dissecting the functional role of the N-terminal domain of the human small heat shock protein HSPB6. PLoS One 2014; 9:e105892. [PMID: 25157403 PMCID: PMC4144951 DOI: 10.1371/journal.pone.0105892] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 07/25/2014] [Indexed: 01/24/2023] Open
Abstract
HSPB6 is a member of the human small heat shock protein (sHSP) family, a conserved group of molecular chaperones that bind partially unfolded proteins and prevent them from aggregating. In vertebrate sHSPs the poorly structured N-terminal domain has been implicated in both chaperone activity and the formation of higher-order oligomers. These two functionally important properties are likely intertwined at the sequence level, complicating attempts to delineate the regions that define them. Differing from the prototypical α-crystallins human HSPB6 has been shown to only form dimers in solution making it more amendable to explore the determinants of chaperoning activity alone. Using a systematic and iterative deletion strategy, we have extensively investigated the role of the N-terminal domain on the chaperone activity of this sHSP. As determined by size-exclusion chromatography and small-angle X-ray scattering, most mutants had a dimeric structure closely resembling that of wild-type HSPB6. The chaperone-like activity was tested using three different substrates, whereby no single truncation, except for complete removal of the N-terminal domain, showed full loss of activity, pointing to the presence of multiple sites for binding unfolding proteins. Intriguingly, we found that the stretch encompassing residues 31 to 35, which is nearly fully conserved across vertebrate sHSPs, acts as a negative regulator of activity, as its deletion greatly enhanced chaperoning capability. Further single point mutational analysis revealed an interplay between the highly conserved residues Q31 and F33 in fine-tuning its function.
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Affiliation(s)
- Michelle Heirbaut
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
| | - Steven Beelen
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
- * E-mail: (SVS); (SDW)
| | - Stephen D. Weeks
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
- * E-mail: (SVS); (SDW)
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Slingsby C, Wistow GJ. Functions of crystallins in and out of lens: roles in elongated and post-mitotic cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:52-67. [PMID: 24582830 PMCID: PMC4104235 DOI: 10.1016/j.pbiomolbio.2014.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 02/18/2014] [Indexed: 12/25/2022]
Abstract
The vertebrate lens evolved to collect light and focus it onto the retina. In development, the lens grows through massive elongation of epithelial cells possibly recapitulating the evolutionary origins of the lens. The refractive index of the lens is largely dependent on high concentrations of soluble proteins called crystallins. All vertebrate lenses share a common set of crystallins from two superfamilies (although other lineage specific crystallins exist). The α-crystallins are small heat shock proteins while the β- and γ-crystallins belong to a superfamily that contains structural proteins of uncertain function. The crystallins are expressed at very high levels in lens but are also found at lower levels in other cells, particularly in retina and brain. All these proteins have plausible connections to maintenance of cytoplasmic order and chaperoning of the complex molecular machines involved in the architecture and function of cells, particularly elongated and post-mitotic cells. They may represent a suite of proteins that help maintain homeostasis in such cells that are at risk from stress or from the accumulated insults of aging.
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Affiliation(s)
- Christine Slingsby
- Department of Biological Sciences, Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK.
| | - Graeme J Wistow
- Section on Molecular Structure and Functional Genomics, National Eye Institute, Bg 6, Rm 106, National Institutes of Health, Bethesda, MD 20892-0608, USA
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Patel S, Vierling E, Tama F. Replica exchange molecular dynamics simulations provide insight into substrate recognition by small heat shock proteins. Biophys J 2014; 106:2644-55. [PMID: 24940782 PMCID: PMC4070073 DOI: 10.1016/j.bpj.2014.04.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 04/20/2014] [Accepted: 04/23/2014] [Indexed: 11/18/2022] Open
Abstract
The small heat shock proteins (sHSPs) are a virtually ubiquitous and diverse group of molecular chaperones that can bind and protect unfolding proteins from irreversible aggregation. It has been suggested that intrinsic disorder of the N-terminal arm (NTA) of sHSPs is important for substrate recognition. To investigate conformations of the NTA that could recognize substrates we performed replica exchange molecular dynamics simulations. Behavior at normal and stress temperatures of the dimeric building blocks of dodecameric HSPs from wheat (Ta16.9) and pea (Ps18.1) were compared because they display high sequence similarity, but Ps18.1 is more efficient in binding specific substrates. In our simulations, the NTAs of the dimer are flexible and dynamic; however, rather than exhibiting highly extended conformations they retain considerable α-helical character and contacts with the conserved α-crystallin domain (ACD). Network analysis and clustering methods reveal that there are two major conformational forms designated either "open" or "closed" based on the relative position of the two NTAs and their hydrophobic solvent accessible surface area. The equilibrium constant for the closed to open transition is significantly different for Ta16.9 and Ps18.1, with the latter showing more open conformations at elevated temperature correlated with its more effective chaperone activity. In addition, the Ps18.1 NTAs have more hydrophobic solvent accessible surface than those of Ta16.9. NTA hydrophobic patches are comparable in size to the area buried in many protein-protein interactions, which would enable sHSPs to bind early unfolding intermediates. Reduced interactions of the Ps18.1 NTAs with each other and with the ACD contribute to the differences in dynamics and hydrophobic surface area of the two sHSPs. These data support a major role for the conformational equilibrium of the NTA in substrate binding and indicate features of the NTA that contribute to sHSP chaperone efficiency.
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Affiliation(s)
- Sunita Patel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, Massachusetts
| | - Florence Tama
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona; RIKEN, Advanced Institute for Computational Sciences, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
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42
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Abstract
Small heat-shock proteins (sHSPs) are ubiquitous ATP-independent molecular chaperones that play crucial roles in protein quality control in cells. They are able to prevent the aggregation and/or inactivation of various non-native substrate proteins and assist the refolding of these substrates independently or under the help of other ATP-dependent chaperones. Substrate recognition and binding by sHSPs are essential for their chaperone functions. This review focuses on what natural substrate proteins an sHSP protects and how it binds the substrates in cells under fluctuating conditions. It appears that sHSPs of prokaryotes, although being able to bind a wide range of cellular proteins, preferentially protect certain classes of functional proteins, such as translation-related proteins and metabolic enzymes, which may well explain why they could increase the resistance of host cells against various stresses. Mechanistically, the sHSPs of prokaryotes appear to possess numerous multi-type substrate-binding residues and are able to hierarchically activate these residues in a temperature-dependent manner, and thus act as temperature-regulated chaperones. The mechanism of hierarchical activation of substrate-binding residues is also discussed regarding its implication for eukaryotic sHSPs.
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Affiliation(s)
- Xinmiao Fu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
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43
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Abstract
A crystal structure of a yeast small heat shock protein reported by Hanazono and colleagues in this issue of Structure reveals the versatility of the α-crystallin domain dimer for building assemblies of different size and symmetry. The domains assemble into a vessel filled with hydrophobic sequence extensions enriched with phenylalanines.
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Affiliation(s)
- Christine Slingsby
- Department of Biological Sciences, Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK.
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