1
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Selig EE, Zlatic CO, Cox D, Mok YF, Gooley PR, Ecroyd H, Griffin MDW. N- and C-terminal regions of αB-crystallin and Hsp27 mediate inhibition of amyloid nucleation, fibril binding, and fibril disaggregation. J Biol Chem 2020; 295:9838-9854. [PMID: 32417755 DOI: 10.1074/jbc.ra120.012748] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/11/2020] [Indexed: 01/08/2023] Open
Abstract
Small heat-shock proteins (sHSPs) are ubiquitously expressed molecular chaperones that inhibit amyloid fibril formation; however, their mechanisms of action remain poorly understood. sHSPs comprise a conserved α-crystallin domain flanked by variable N- and C-terminal regions. To investigate the functional contributions of these three regions, we compared the chaperone activities of various constructs of human αB-crystallin (HSPB5) and heat-shock 27-kDa protein (Hsp27, HSPB1) during amyloid formation by α-synuclein and apolipoprotein C-II. Using an array of approaches, including thioflavin T fluorescence assays and sedimentation analysis, we found that the N-terminal region of Hsp27 and the terminal regions of αB-crystallin are important for delaying amyloid fibril nucleation and for disaggregating mature apolipoprotein C-II fibrils. We further show that the terminal regions are required for stable fibril binding by both sHSPs and for mediating lateral fibril-fibril association, which sequesters preformed fibrils into large aggregates and is believed to have a cytoprotective function. We conclude that although the isolated α-crystallin domain retains some chaperone activity against amyloid formation, the flanking domains contribute additional and important chaperone activities, both in delaying amyloid formation and in mediating interactions of sHSPs with amyloid aggregates. Both these chaperone activities have significant implications for the pathogenesis and progression of diseases associated with amyloid deposition, such as Parkinson's and Alzheimer's diseases.
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Affiliation(s)
- Emily E Selig
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Courtney O Zlatic
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Dezerae Cox
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Yee-Foong Mok
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Paul R Gooley
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Heath Ecroyd
- Molecular Horizons and the School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia.,Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia .,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
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2
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Iburg M, Puchkov D, Rosas-Brugada IU, Bergemann L, Rieprecht U, Kirstein J. The noncanonical small heat shock protein HSP-17 from Caenorhabditis elegans is a selective protein aggregase. J Biol Chem 2020; 295:3064-3079. [PMID: 32001616 DOI: 10.1074/jbc.ra119.011185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/22/2020] [Indexed: 12/14/2022] Open
Abstract
Small heat shock proteins (sHsps) are conserved, ubiquitous members of the proteostasis network. Canonically, they act as "holdases" and buffer unfolded or misfolded proteins against aggregation in an ATP-independent manner. Whereas bacteria and yeast each have only two sHsps in their genomes, this number is higher in metazoan genomes, suggesting a spatiotemporal and functional specialization in higher eukaryotes. Here, using recombinantly expressed and purified proteins, static light-scattering analysis, and disaggregation assays, we report that the noncanonical sHsp HSP-17 of Caenorhabditis elegans facilitates aggregation of model substrates, such as malate dehydrogenase (MDH), and inhibits disaggregation of luciferase in vitro Experiments with fluorescently tagged HSP-17 under the control of its endogenous promoter revealed that HSP-17 is expressed in the digestive and excretory organs, where its overexpression promotes the aggregation of polyQ proteins and of the endogenous kinase KIN-19. Systemic depletion of hsp-17 shortens C. elegans lifespan and severely reduces fecundity and survival upon prolonged heat stress. HSP-17 is an abundant protein exhibiting opposing chaperone activities on different substrates, indicating that it is a selective protein aggregase with physiological roles in development, digestion, and osmoregulation.
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Affiliation(s)
- Manuel Iburg
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Dmytro Puchkov
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Irving U Rosas-Brugada
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Linda Bergemann
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Ulrike Rieprecht
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany
| | - Janine Kirstein
- Leibniz Research Institute for Molecular Pharmacology im Forschungsverbund Berlin e.V., R.-Roessle-Strasse 10, 13125 Berlin, Germany; Faculty 2, Cell Biology, University of Bremen, Leobener Strasse, 28359 Bremen, Germany.
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3
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Gliniewicz EF, Chambers KM, De Leon ER, Sibai D, Campbell HC, McMenimen KA. Chaperone-like activity of the N-terminal region of a human small heat shock protein and chaperone-functionalized nanoparticles. Proteins 2019; 87:401-415. [PMID: 30684363 DOI: 10.1002/prot.25662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/03/2019] [Accepted: 01/22/2019] [Indexed: 11/10/2022]
Abstract
Small heat shock proteins (sHsps) are molecular chaperones employed to interact with a diverse range of substrates as the first line of defense against cellular protein aggregation. The N-terminal region (NTR) is implicated in defining features of sHsps; notably in their ability to form dynamic and polydisperse oligomers, and chaperone activity. The physiological relevance of oligomerization and chemical-scale mode(s) of chaperone function remain undefined. We present novel chemical tools to investigate chaperone activity and substrate specificity of human HspB1 (B1NTR), through isolation of B1NTR and development of peptide-conjugated gold nanoparticles (AuNPs). We demonstrate that B1NTR exhibits chaperone capacity for some substrates, determined by anti-aggregation assays and size-exclusion chromatography. The importance of protein dynamics and multivalency on chaperone capacity was investigated using B1NTR-conjugated AuNPs, which exhibit concentration-dependent chaperone activity for some substrates. Our results implicate sHsp NTRs in chaperone activity, and demonstrate the therapeutic potential of sHsp-AuNPs in rescuing aberrant protein aggregation.
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Affiliation(s)
- Emily F Gliniewicz
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts
| | - Kelly M Chambers
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts
| | | | - Diana Sibai
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts
| | - Helen C Campbell
- Department of Chemistry, Mount Holyoke College, South Hadley, Massachusetts
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4
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Miyawaki S, Uemura Y, Hongo K, Kawata Y, Mizobata T. Acid-denatured small heat shock protein HdeA from Escherichia coli forms reversible fibrils with an atypical secondary structure. J Biol Chem 2018; 294:1590-1601. [PMID: 30530490 DOI: 10.1074/jbc.ra118.005611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/06/2018] [Indexed: 12/13/2022] Open
Abstract
The periplasmic small heat shock protein HdeA from Escherichia coli is inactive under normal growth conditions (at pH 7) and activated only when E. coli cells are subjected to a sudden decrease in pH, converting HdeA into an acid-denatured active state. Here, using in vitro fibrillation assays, transmission EM, atomic-force microscopy, and CD analyses, we found that when HdeA is active as a molecular chaperone, it is also capable of forming inactive aggregates that, at first glance, resemble amyloid fibrils. We noted that the molecular chaperone activity of HdeA takes precedence over fibrillogenesis under acidic conditions, as the presence of denatured substrate protein was sufficient to suppress HdeA fibril formation. Further experiments suggested that the secondary structure of HdeA fibrils deviates somewhat from typical amyloid fibrils and contains α-helices. Strikingly, HdeA fibrils that formed at pH 2 were immediately resolubilized by a simple shift to pH 7 and from there could regain molecular chaperone activity upon a return to pH 1. HdeA, therefore, provides an unusual example of a "reversible" form of protein fibrillation with an atypical secondary structure composition. The competition between active assistance of denatured polypeptides (its "molecular chaperone" activity) and the formation of inactive fibrillary deposits (its "fibrillogenic" activity) provides a unique opportunity to probe the relationship among protein function, structure, and aggregation in detail.
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Affiliation(s)
- Shiori Miyawaki
- Graduate School of Sustainability Science, Tottori University, Tottori 680-8552, Japan
| | - Yumi Uemura
- Department of Engineering, Tottori University, Tottori 680-8552, Japan
| | - Kunihiro Hongo
- Graduate School of Sustainability Science, Tottori University, Tottori 680-8552, Japan; Department of Engineering, Tottori University, Tottori 680-8552, Japan; Center for Research on Green Sustainable Chemistry, Tottori University, Tottori 680-8552, Japan
| | - Yasushi Kawata
- Graduate School of Sustainability Science, Tottori University, Tottori 680-8552, Japan; Department of Engineering, Tottori University, Tottori 680-8552, Japan; Center for Research on Green Sustainable Chemistry, Tottori University, Tottori 680-8552, Japan
| | - Tomohiro Mizobata
- Graduate School of Sustainability Science, Tottori University, Tottori 680-8552, Japan; Department of Engineering, Tottori University, Tottori 680-8552, Japan; Center for Research on Green Sustainable Chemistry, Tottori University, Tottori 680-8552, Japan.
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5
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Park AM, Tsunoda I, Yoshie O. Heat shock protein 27 promotes cell cycle progression by down-regulating E2F transcription factor 4 and retinoblastoma family protein p130. J Biol Chem 2018; 293:15815-15826. [PMID: 30166342 DOI: 10.1074/jbc.ra118.003310] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/23/2018] [Indexed: 02/05/2023] Open
Abstract
Heat shock protein 27 (HSP27) protects cells under stress. Here, we demonstrate that HSP27 also promotes cell cycle progression of MRC-5 human lung fibroblast cells. Serum starvation for 24 h induced G1 arrest in these cells, and upon serum refeeding, the cells initiated cell cycle progression accompanied by an increase in HSP27 protein levels. HSP27 levels peaked at 12 h, and transcriptional up-regulation of six G2/M-related genes (CCNA2, CCNB1, CCNB2, CDC25C, CDCA3, and CDK1) peaked at 24-48 h. siRNA-mediated HSP27 silencing in proliferating MRC-5 cells induced G2 arrest coinciding with down-regulation of these six genes. Of note, the promoters of all of these genes have the cell cycle-dependent element and/or the cell cycle gene-homology region. These promoter regions are known to be bound by the E2F family proteins (E2F-1 to E2F-8) and retinoblastoma (RB) family proteins (RB1, p107, and p130), among which E2F-4 and p130 were strongly up-regulated in HSP27-knockdown cells. E2F-4 or p130 knockdown concomitant with the HSP27 knockdown rescued MRC-5 cells from G2 arrest and up-regulated the six cell cycle genes. Moreover, we observed cellular senescence in MRC-5 cells on day 3 after the HSP27 knockdown, as evidenced by increased senescence-associated β-gal activity and up-regulated inflammatory cytokines. The cellular senescence was also suppressed by the concomitant knockdown of E2F-4/HSP27 or p130/HSP27. Our findings indicate that HSP27 promotes cell cycle progression of MRC-5 cells by suppressing expression of the transcriptional repressors E2F-4 and p130.
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Affiliation(s)
- Ah-Mee Park
- From the Department of Microbiology, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan and
| | - Ikuo Tsunoda
- From the Department of Microbiology, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan and
| | - Osamu Yoshie
- From the Department of Microbiology, Kindai University Faculty of Medicine, Osakasayama, Osaka 589-8511, Japan and.,the Health and Kampo Institute, 1-11-10 Murasakiyama, Sendai, Miyagi 981-3205, Japan
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7
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Baughman HER, Clouser AF, Klevit RE, Nath A. HspB1 and Hsc70 chaperones engage distinct tau species and have different inhibitory effects on amyloid formation. J Biol Chem 2018; 293:2687-2700. [PMID: 29298892 DOI: 10.1074/jbc.m117.803411] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 12/15/2017] [Indexed: 11/06/2022] Open
Abstract
The microtubule-associated protein tau forms insoluble, amyloid-type aggregates in various dementias, most notably Alzheimer's disease. Cellular chaperone proteins play important roles in maintaining protein solubility and preventing aggregation in the crowded cellular environment. Although tau is known to interact with numerous chaperones, it remains unclear how these chaperones function mechanistically to prevent tau aggregation and how chaperones from different classes compare in terms of mechanism. Here, we focused on the small heat shock protein HspB1 (also known as Hsp27) and the constitutive chaperone Hsc70 (also known as HspA8) and report how each chaperone interacts with tau to prevent its fibril formation. Using fluorescence and NMR spectroscopy, we show that the two chaperones inhibit tau fibril formation by distinct mechanisms. HspB1 delayed tau fibril formation by weakly interacting with early species in the aggregation process, whereas Hsc70 was highly efficient at preventing tau fibril elongation, possibly by capping the ends of tau fibrils. Both chaperones recognized aggregation-prone motifs within the microtubule-binding repeat region of tau. However, HspB1 binding remained transient in both aggregation-promoting and non-aggregating conditions, whereas Hsc70 binding was significantly tighter under aggregation-promoting conditions. These differences highlight the fact that chaperones from different families play distinct but complementary roles in the prevention of pathological protein aggregation.
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Affiliation(s)
- Hannah E R Baughman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610
| | - Amanda F Clouser
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350
| | - Rachel E Klevit
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350.
| | - Abhinav Nath
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195-7610.
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8
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Mishra S, Wu SY, Fuller AW, Wang Z, Rose KL, Schey KL, Mchaourab HS. Loss of αB-crystallin function in zebrafish reveals critical roles in the development of the lens and stress resistance of the heart. J Biol Chem 2017; 293:740-753. [PMID: 29162721 DOI: 10.1074/jbc.m117.808634] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/17/2017] [Indexed: 12/12/2022] Open
Abstract
Genetic mutations in the human small heat shock protein αB-crystallin have been implicated in autosomal cataracts and skeletal myopathies, including heart muscle diseases (cardiomyopathy). Although these mutations lead to modulation of their chaperone activity in vitro, the in vivo functions of αB-crystallin in the maintenance of both lens transparency and muscle integrity remain unclear. This lack of information has hindered a mechanistic understanding of these diseases. To better define the functional roles of αB-crystallin, we generated loss-of-function zebrafish mutant lines by utilizing the CRISPR/Cas9 system to specifically disrupt the two αB-crystallin genes, αBa and αBb We observed lens abnormalities in the mutant lines of both genes, and the penetrance of the lens phenotype was higher in αBa than αBb mutants. This finding is in contrast with the lack of a phenotype previously reported in αB-crystallin knock-out mice and suggests that the elevated chaperone activity of the two zebrafish orthologs is critical for lens development. Besides its key role in the lens, we uncovered another critical role for αB-crystallin in providing stress tolerance to the heart. The αB-crystallin mutants exhibited hypersusceptibility to develop pericardial edema when challenged by crowding stress or exposed to elevated cortisol stress, both of which activate glucocorticoid receptor signaling. Our work illuminates the involvement of αB-crystallin in stress tolerance of the heart presumably through the proteostasis network and reinforces the critical role of the chaperone activity of αB-crystallin in the maintenance of lens transparency.
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Affiliation(s)
- Sanjay Mishra
- From the Departments of Molecular Physiology and Biophysics and
| | - Shu-Yu Wu
- From the Departments of Molecular Physiology and Biophysics and
| | | | - Zhen Wang
- Biochemistry and.,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Kristie L Rose
- Biochemistry and.,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Kevin L Schey
- Biochemistry and.,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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9
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Mymrikov EV, Daake M, Richter B, Haslbeck M, Buchner J. The Chaperone Activity and Substrate Spectrum of Human Small Heat Shock Proteins. J Biol Chem 2016; 292:672-684. [PMID: 27909051 DOI: 10.1074/jbc.m116.760413] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 11/12/2016] [Indexed: 11/06/2022] Open
Abstract
Small heat shock proteins (sHsps) are a ubiquitous family of molecular chaperones that suppress the unspecific aggregation of miscellaneous proteins. Multicellular organisms contain a large number of different sHsps, raising questions as to whether they function redundantly or are specialized in terms of substrates and mechanism. To gain insight into this issue, we undertook a comparative analysis of the eight major human sHsps on the aggregation of both model proteins and cytosolic lysates under standardized conditions. We discovered that sHsps, which form large oligomers (HspB1/Hsp27, HspB3, HspB4/αA-crystallin, and HspB5/αB-crystallin) are promiscuous chaperones, whereas the chaperone activity of the other sHsps is more substrate-dependent. However, all human sHsps analyzed except HspB7 suppressed the aggregation of cytosolic proteins of HEK293 cells. We identified ∼1100 heat-sensitive HEK293 proteins, 12% of which could be isolated in complexes with sHsps. Analysis of their biochemical properties revealed that most of the sHsp substrates have a molecular mass from 50 to 100 kDa and a slightly acidic pI (5.4-6.8). The potency of the sHsps to suppress aggregation of model substrates is correlated with their ability to form stable substrate complexes; especially HspB1 and HspB5, but also B3, bind tightly to a variety of proteins, whereas fewer substrates were detected in complex with the other sHsps, although these were also efficient in preventing the aggregation of cytosolic proteins.
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Affiliation(s)
- Evgeny V Mymrikov
- From the Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Marina Daake
- From the Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Bettina Richter
- From the Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Martin Haslbeck
- From the Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Johannes Buchner
- From the Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
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10
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Wu SY, Zou P, Fuller AW, Mishra S, Wang Z, Schey KL, Mchaourab HS. Expression of Cataract-linked γ-Crystallin Variants in Zebrafish Reveals a Proteostasis Network That Senses Protein Stability. J Biol Chem 2016; 291:25387-25397. [PMID: 27770023 DOI: 10.1074/jbc.m116.749606] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/21/2016] [Indexed: 11/06/2022] Open
Abstract
The refractivity and transparency of the ocular lens is dependent on the stability and solubility of the crystallins in the fiber cells. A number of mutations of lens crystallins have been associated with dominant cataracts in humans and mice. Of particular interest were γB- and γD-crystallin mutants linked to dominant cataracts in mouse models. Although thermodynamically destabilized and aggregation-prone, these mutants were found to have weak affinity to the resident chaperone α-crystallin in vitro To better understand the mechanism of the cataract phenotype, we transgenically expressed different γD-crystallin mutants in the zebrafish lens and observed a range of lens defects that arise primarily from the aggregation of the mutant proteins. Unlike mouse models, a strong correlation was observed between the severity and penetrance of the phenotype and the level of destabilization of the mutant. We interpret this result to reflect the presence of a proteostasis network that can "sense" protein stability. In the more destabilized mutants, the capacity of this network is overwhelmed, leading to the observed increase in phenotypic penetrance. Overexpression of αA-crystallin had no significant effects on the penetrance of lens defects, suggesting that its chaperone capacity is not limiting. Although consistent with the prevailing hypothesis that a chaperone network is required for lens transparency, our results suggest that αA-crystallin may not be efficient to inhibit aggregation of lens γ-crystallin. Furthermore, our work implicates additional inputs/factors in this underlying proteostasis network and demonstrates the utility of zebrafish as a platform to delineate mechanisms of cataract.
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Affiliation(s)
- Shu-Yu Wu
- From the Departments of Molecular Physiology and Biophysics and
| | - Ping Zou
- From the Departments of Molecular Physiology and Biophysics and
| | | | - Sanjay Mishra
- From the Departments of Molecular Physiology and Biophysics and
| | - Zhen Wang
- Biochemistry and.,the Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Kevin L Schey
- Biochemistry and.,the Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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11
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Cox D, Selig E, Griffin MDW, Carver JA, Ecroyd H. Small Heat-shock Proteins Prevent α-Synuclein Aggregation via Transient Interactions and Their Efficacy Is Affected by the Rate of Aggregation. J Biol Chem 2016; 291:22618-22629. [PMID: 27587396 DOI: 10.1074/jbc.m116.739250] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/30/2016] [Indexed: 12/21/2022] Open
Abstract
The aggregation of α-synuclein (α-syn) into amyloid fibrils is associated with neurodegenerative diseases, collectively referred to as the α-synucleinopathies. In vivo, molecular chaperones, such as the small heat-shock proteins (sHsps), normally act to prevent protein aggregation; however, it remains to be determined how aggregation-prone α-syn evades sHsp chaperone action leading to its disease-associated deposition. This work examines the molecular mechanism by which two canonical sHsps, αB-crystallin (αB-c) and Hsp27, interact with aggregation-prone α-syn to prevent its aggregation in vitro Both sHsps are very effective inhibitors of α-syn aggregation, but no stable complex between the sHsps and α-syn was detected, indicating that the sHsps inhibit α-syn aggregation via transient interactions. Moreover, the ability of these sHsps to prevent α-syn aggregation was dependent on the kinetics of aggregation; the faster the rate of aggregation (shorter the lag phase), the less effective the sHsps were at inhibiting fibril formation of α-syn. Thus, these findings indicate that the rate at which α-syn aggregates in cells may be a significant factor in how it evades sHsp chaperone action in the α-synucleinopathies.
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Affiliation(s)
- Dezerae Cox
- From the Illawarra Health and Medical Research Institute and.,School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522
| | - Emily Selig
- the Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3052, and
| | - Michael D W Griffin
- the Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3052, and
| | - John A Carver
- the Research School of Chemistry, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Heath Ecroyd
- From the Illawarra Health and Medical Research Institute and .,School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522
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12
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Donovan MR, Marr MT. dFOXO Activates Large and Small Heat Shock Protein Genes in Response to Oxidative Stress to Maintain Proteostasis in Drosophila. J Biol Chem 2016; 291:19042-50. [PMID: 27435672 DOI: 10.1074/jbc.m116.723049] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Indexed: 12/11/2022] Open
Abstract
Maintaining protein homeostasis is critical for survival at the cellular and organismal level (Morimoto, R. I. (2011) Cold Spring Harb. Symp. Quant. Biol. 76, 91-99). Cells express a family of molecular chaperones, the heat shock proteins, during times of oxidative stress to protect against proteotoxicity. We have identified a second stress responsive transcription factor, dFOXO, that works alongside the heat shock transcription factor to activate transcription of both the small heat shock protein and the large heat shock protein genes. This expression likely protects cells from protein misfolding associated with oxidative stress. Here we identify the regions of the Hsp70 promoter essential for FOXO-dependent transcription using in vitro methods and find a physiological role for FOXO-dependent expression of heat shock proteins in vivo.
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Affiliation(s)
- Marissa R Donovan
- From the Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02453
| | - Michael T Marr
- From the Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02453
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13
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Mitzelfelt KA, Limphong P, Choi MJ, Kondrat FDL, Lai S, Kolander KD, Kwok WM, Dai Q, Grzybowski MN, Zhang H, Taylor GM, Lui Q, Thao MT, Hudson JA, Barresi R, Bushby K, Jungbluth H, Wraige E, Geurts AM, Benesch JLP, Riedel M, Christians ES, Minella AC, Benjamin IJ. The Human 343delT HSPB5 Chaperone Associated with Early-onset Skeletal Myopathy Causes Defects in Protein Solubility. J Biol Chem 2016; 291:14939-53. [PMID: 27226619 PMCID: PMC4946913 DOI: 10.1074/jbc.m116.730481] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/14/2016] [Indexed: 12/23/2022] Open
Abstract
Mutations of HSPB5 (also known as CRYAB or αB-crystallin), a bona fide heat shock protein and molecular chaperone encoded by the HSPB5 (crystallin, alpha B) gene, are linked to multisystem disorders featuring variable combinations of cataracts, cardiomyopathy, and skeletal myopathy. This study aimed to investigate the pathological mechanisms involved in an early-onset myofibrillar myopathy manifesting in a child harboring a homozygous recessive mutation in HSPB5, 343delT. To study HSPB5 343delT protein dynamics, we utilize model cell culture systems including induced pluripotent stem cells derived from the 343delT patient (343delT/343delT) along with isogenic, heterozygous, gene-corrected control cells (WT KI/343delT) and BHK21 cells, a cell line lacking endogenous HSPB5 expression. 343delT/343delT and WT KI/343delT-induced pluripotent stem cell-derived skeletal myotubes and cardiomyocytes did not express detectable levels of 343delT protein, contributable to the extreme insolubility of the mutant protein. Overexpression of HSPB5 343delT resulted in insoluble mutant protein aggregates and induction of a cellular stress response. Co-expression of 343delT with WT prevented visible aggregation of 343delT and improved its solubility. Additionally, in vitro refolding of 343delT in the presence of WT rescued its solubility. We demonstrate an interaction between WT and 343delT both in vitro and within cells. These data support a loss-of-function model for the myopathy observed in the patient because the insoluble mutant would be unavailable to perform normal functions of HSPB5, although additional gain-of-function effects of the mutant protein cannot be excluded. Additionally, our data highlight the solubilization of 343delT by WT, concordant with the recessive inheritance of the disease and absence of symptoms in carrier individuals.
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Affiliation(s)
- Katie A Mitzelfelt
- From the Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112-5650
| | | | | | - Frances D L Kondrat
- the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | | | | | - Wai-Meng Kwok
- Departments of Anesthesiology and Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | | | | | - Huali Zhang
- the Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha City, Hunan 410078, China
| | - Graydon M Taylor
- the Division of Cardiology, Department of Medicine, University of Utah, Salt Lake City, Utah 84132
| | - Qiang Lui
- the Division of Cardiology, Department of Medicine, University of Utah, Salt Lake City, Utah 84132
| | | | - Judith A Hudson
- the Northern Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Rita Barresi
- the National Health Service England Health Science Services for Rare Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne NE2 4AZ, United Kingdom
| | - Kate Bushby
- Neuromuscular Genetics, Newcastle University John Walton Centre for Muscular Dystrophy Research, Medical Research Council Centre for Neuromuscular Diseases, Institute of Genetic Medicine, International Centre for Life, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Heinz Jungbluth
- the Department of Paediatric Neurology, Neuromuscular Service Evelina Children's Hospital, Guy's and St. Thomas' National Health Service Foundation Trust, London SE1 7EH, United Kingdom, the Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College London, London SE1 1UL, United Kingdom, the Department of Basic and Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience, King's College London SE5 9RX, United Kingdom
| | - Elizabeth Wraige
- the Department of Paediatric Neurology, Neuromuscular Service Evelina Children's Hospital, Guy's and St. Thomas' National Health Service Foundation Trust, London SE1 7EH, United Kingdom
| | | | - Justin L P Benesch
- the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | | | - Elisabeth S Christians
- the Sorbonne Universités, University Pierre and Marie Curie, Univ Paris 06, CNRS, Laboratoire de Biologie du Dévelopment de Villefranche sur mer (LBDV), UMR 7009, 181 Chemin du Lazaret, 06230 Villefranche sur mer, France, and
| | - Alex C Minella
- the Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin 53226
| | - Ivor J Benjamin
- From the Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112-5650, the Cardiovascular Center,
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14
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Gangalum RK, Bhat AM, Kohan SA, Bhat SP. Inhibition of the Expression of the Small Heat Shock Protein αB-Crystallin Inhibits Exosome Secretion in Human Retinal Pigment Epithelial Cells in Culture. J Biol Chem 2016; 291:12930-42. [PMID: 27129211 DOI: 10.1074/jbc.m115.698530] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Indexed: 01/15/2023] Open
Abstract
Exosomes carry cell type-specific molecular cargo to extracellular destinations and therefore act as lateral vectors of intercellular communication and transfer of genetic information from one cell to the other. We have shown previously that the small heat shock protein αB-crystallin (αB) is exported out of the adult human retinal pigment epithelial cells (ARPE19) packaged in exosomes. Here, we demonstrate that inhibition of the expression of αB via shRNA inhibits exosome secretion from ARPE19 cells indicating that exosomal cargo may have a role in exosome biogenesis (synthesis and/or secretion). Sucrose density gradient fractionation of the culture medium and cellular extracts suggests continued synthesis of exosomes but an inhibition of exosome secretion. In cells where αB expression was inhibited, the distribution of CD63 (LAMP3), an exosome marker, is markedly altered from the normal dispersed pattern to a stacked perinuclear presence. Interestingly, the total anti-CD63(LAMP3) immunofluorescence in the native and αB-inhibited cells remains unchanged suggesting continued exosome synthesis under conditions of impaired exosome secretion. Importantly, inhibition of the expression of αB results in a phenotype of the RPE cell that contains an increased number of vacuoles and enlarged (fused) vesicles that show increased presence of CD63(LAMP3) and LAMP1 indicating enhancement of the endolysosomal compartment. This is further corroborated by increased Rab7 labeling of this compartment (RabGTPase 7 is known to be associated with late endosome maturation). These data collectively point to a regulatory role for αB in exosome biogenesis possibly via its involvement at a branch point in the endocytic pathway that facilitates secretion of exosomes.
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Affiliation(s)
| | - Ankur M Bhat
- From the Jules Stein Eye Institute, Geffen School of Medicine
| | - Sirus A Kohan
- Brain Research Institute, UCLA, Los Angeles, California 90095
| | - Suraj P Bhat
- From the Jules Stein Eye Institute, Geffen School of Medicine, Brain Research Institute, UCLA, Los Angeles, California 90095 Molecular Biology Institute and
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15
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Tsai CJ, Aslam K, Drendel HM, Asiago JM, Goode KM, Paul LN, Rochet JC, Hazbun TR. Hsp31 Is a Stress Response Chaperone That Intervenes in the Protein Misfolding Process. J Biol Chem 2015; 290:24816-34. [PMID: 26306045 DOI: 10.1074/jbc.m115.678367] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Indexed: 12/17/2022] Open
Abstract
The Saccharomyces cerevisiae heat shock protein Hsp31 is a stress-inducible homodimeric protein that is involved in diauxic shift reprogramming and has glyoxalase activity. We show that substoichiometric concentrations of Hsp31 can abrogate aggregation of a broad array of substrates in vitro. Hsp31 also modulates the aggregation of α-synuclein (αSyn), a target of the chaperone activity of human DJ-1, an Hsp31 homolog. We demonstrate that Hsp31 is able to suppress the in vitro fibrillization or aggregation of αSyn, citrate synthase and insulin. Chaperone activity was also observed in vivo because constitutive overexpression of Hsp31 reduced the incidence of αSyn cytoplasmic foci, and yeast cells were rescued from αSyn-generated proteotoxicity upon Hsp31 overexpression. Moreover, we showed that Hsp31 protein levels are increased by H2O2, in the diauxic phase of normal growth conditions, and in cells under αSyn-mediated proteotoxic stress. We show that Hsp31 chaperone activity and not the methylglyoxalase activity or the autophagy pathway drives the protective effects. We also demonstrate reduced aggregation of the Sup35 prion domain, PrD-Sup35, as visualized by fluorescent protein fusions. In addition, Hsp31 acts on its substrates prior to the formation of large aggregates because Hsp31 does not mutually localize with prion aggregates, and it prevents the formation of detectable in vitro αSyn fibrils. These studies establish that the protective role of Hsp31 against cellular stress is achieved by chaperone activity that intervenes early in the protein misfolding process and is effective on a wide spectrum of substrate proteins, including αSyn and prion proteins.
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Affiliation(s)
- Chai-Jui Tsai
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Kiran Aslam
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Holli M Drendel
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Josephat M Asiago
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Kourtney M Goode
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Lake N Paul
- the Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
| | - Jean-Christophe Rochet
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Tony R Hazbun
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
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