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The Role of Small Heat Shock Proteins in Protein Misfolding Associated Motoneuron Diseases. Int J Mol Sci 2022; 23:ijms231911759. [PMID: 36233058 PMCID: PMC9569637 DOI: 10.3390/ijms231911759] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Motoneuron diseases (MNDs) are neurodegenerative conditions associated with death of upper and/or lower motoneurons (MNs). Proteostasis alteration is a pathogenic mechanism involved in many MNDs and is due to the excessive presence of misfolded and aggregated proteins. Protein misfolding may be the product of gene mutations, or due to defects in the translation process, or to stress agents; all these conditions may alter the native conformation of proteins making them prone to aggregate. Alternatively, mutations in members of the protein quality control (PQC) system may determine a loss of function of the proteostasis network. This causes an impairment in the capability to handle and remove aberrant or damaged proteins. The PQC system consists of the degradative pathways, which are the autophagy and the proteasome, and a network of chaperones and co-chaperones. Among these components, Heat Shock Protein 70 represents the main factor in substrate triage to folding, refolding, or degradation, and it is assisted in this task by a subclass of the chaperone network, the small heat shock protein (sHSPs/HSPBs) family. HSPBs take part in proteostasis by bridging misfolded and aggregated proteins to the HSP70 machinery and to the degradative pathways, facilitating refolding or clearance of the potentially toxic proteins. Because of its activity against proteostasis alteration, the chaperone system plays a relevant role in the protection against proteotoxicity in MNDs. Here, we discuss the role of HSPBs in MNDs and which HSPBs may represent a valid target for therapeutic purposes.
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Tedesco B, Cristofani R, Ferrari V, Cozzi M, Rusmini P, Casarotto E, Chierichetti M, Mina F, Galbiati M, Piccolella M, Crippa V, Poletti A. Insights on Human Small Heat Shock Proteins and Their Alterations in Diseases. Front Mol Biosci 2022; 9:842149. [PMID: 35281256 PMCID: PMC8913478 DOI: 10.3389/fmolb.2022.842149] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
The family of the human small Heat Shock Proteins (HSPBs) consists of ten members of chaperones (HSPB1-HSPB10), characterized by a low molecular weight and capable of dimerization and oligomerization forming large homo- or hetero-complexes. All HSPBs possess a highly conserved centrally located α-crystallin domain and poorly conserved N- and C-terminal domains. The main feature of HSPBs is to exert cytoprotective functions by preserving proteostasis, assuring the structural maintenance of the cytoskeleton and acting in response to cellular stresses and apoptosis. HSPBs take part in cell homeostasis by acting as holdases, which is the ability to interact with a substrate preventing its aggregation. In addition, HSPBs cooperate in substrates refolding driven by other chaperones or, alternatively, promote substrate routing to degradation. Notably, while some HSPBs are ubiquitously expressed, others show peculiar tissue-specific expression. Cardiac muscle, skeletal muscle and neurons show high expression levels for a wide variety of HSPBs. Indeed, most of the mutations identified in HSPBs are associated to cardiomyopathies, myopathies, and motor neuropathies. Instead, mutations in HSPB4 and HSPB5, which are also expressed in lens, have been associated with cataract. Mutations of HSPBs family members encompass base substitutions, insertions, and deletions, resulting in single amino acid substitutions or in the generation of truncated or elongated proteins. This review will provide an updated overview of disease-related mutations in HSPBs focusing on the structural and biochemical effects of mutations and their functional consequences.
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Affiliation(s)
- B. Tedesco
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - R. Cristofani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - V. Ferrari
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Cozzi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - P. Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - E. Casarotto
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Chierichetti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - F. Mina
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Galbiati
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - M. Piccolella
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - V. Crippa
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - A. Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
- *Correspondence: A. Poletti,
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Tiago T, Hummel B, Morelli FF, Basile V, Vinet J, Galli V, Mediani L, Antoniani F, Pomella S, Cassandri M, Garone MG, Silvestri B, Cimino M, Cenacchi G, Costa R, Mouly V, Poser I, Yeger-Lotem E, Rosa A, Alberti S, Rota R, Ben-Zvi A, Sawarkar R, Carra S. Small heat-shock protein HSPB3 promotes myogenesis by regulating the lamin B receptor. Cell Death Dis 2021; 12:452. [PMID: 33958580 PMCID: PMC8102500 DOI: 10.1038/s41419-021-03737-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 02/03/2023]
Abstract
One of the critical events that regulates muscle cell differentiation is the replacement of the lamin B receptor (LBR)-tether with the lamin A/C (LMNA)-tether to remodel transcription and induce differentiation-specific genes. Here, we report that localization and activity of the LBR-tether are crucially dependent on the muscle-specific chaperone HSPB3 and that depletion of HSPB3 prevents muscle cell differentiation. We further show that HSPB3 binds to LBR in the nucleoplasm and maintains it in a dynamic state, thus promoting the transcription of myogenic genes, including the genes to remodel the extracellular matrix. Remarkably, HSPB3 overexpression alone is sufficient to induce the differentiation of two human muscle cell lines, LHCNM2 cells, and rhabdomyosarcoma cells. We also show that mutant R116P-HSPB3 from a myopathy patient with chromatin alterations and muscle fiber disorganization, forms nuclear aggregates that immobilize LBR. We find that R116P-HSPB3 is unable to induce myoblast differentiation and instead activates the unfolded protein response. We propose that HSPB3 is a specialized chaperone engaged in muscle cell differentiation and that dysfunctional HSPB3 causes neuromuscular disease by deregulating LBR.
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Affiliation(s)
- Tatiana Tiago
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Barbara Hummel
- Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Federica F Morelli
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Valentina Basile
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Jonathan Vinet
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Veronica Galli
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Laura Mediani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Francesco Antoniani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Silvia Pomella
- Department of Oncohematology, Bambino Gesù Children's Hospital, IRCCS, 00165, Rome, Italy
| | - Matteo Cassandri
- Department of Oncohematology, Bambino Gesù Children's Hospital, IRCCS, 00165, Rome, Italy
| | - Maria Giovanna Garone
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
| | - Beatrice Silvestri
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161, Rome, Italy
| | - Marco Cimino
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy
| | - Giovanna Cenacchi
- Department of Biomedical and Neuromotor Sciences DIBINEM, University of Bologna, Bologna, Italy; Centre for Applied Biomedical Research - CRBA, University of Bologna, IRCCS St. Orsola Hospital, Bologna, Italy
| | - Roberta Costa
- Department of Biomedical and Neuromotor Sciences DIBINEM, University of Bologna, Bologna, Italy; Centre for Applied Biomedical Research - CRBA, University of Bologna, IRCCS St. Orsola Hospital, Bologna, Italy
| | - Vincent Mouly
- Centre de Recherche en Myologie, Sorbonne Université, Inserm, Institut de Myologie, F-75013, Paris, France
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
- Dewpoint Therapeutics GmbH, Tatzberg 47, 01307, Dresden, Germany
| | - Esti Yeger-Lotem
- Department of Clinical Biochemistry and Pharmacology and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel
| | - Alessandro Rosa
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161, Rome, Italy
| | - Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Rossella Rota
- Department of Oncohematology, Bambino Gesù Children's Hospital, IRCCS, 00165, Rome, Italy
| | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel
| | - Ritwick Sawarkar
- Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Medical Research Council (MRC), University of Cambridge, Cambridge, CB2 1QR, UK
| | - Serena Carra
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125, Modena, Italy.
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Yang L, Qin Y, Jian C. Screening for Core Genes Related to Pathogenesis of Alzheimer's Disease. Front Cell Dev Biol 2021; 9:668738. [PMID: 33968940 PMCID: PMC8101499 DOI: 10.3389/fcell.2021.668738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/01/2021] [Indexed: 12/18/2022] Open
Abstract
Alzheimer’s disease (AD), a nervous system disease, lacks effective therapies at present. RNA expression is the basic way to regulate life activities, and identifying related characteristics in AD patients may aid the exploration of AD pathogenesis and treatment. This study developed a classifier that could accurately classify AD patients and healthy people, and then obtained 3 core genes that may be related to the pathogenesis of AD. To this end, RNA expression data of the middle temporal gyrus of AD patients were firstly downloaded from GEO database, and the data were then normalized using limma package following a supplementation of missing data by k-Nearest Neighbor (KNN) algorithm. Afterwards, the top 500 genes of the most feature importance were obtained through Max-Relevance and Min-Redundancy (mRMR) analysis, and based on these genes, a series of AD classifiers were constructed through Support Vector Machine (SVM), Random Forest (RF), and KNN algorithms. Then, the KNN classifier with the highest Matthews correlation coefficient (MCC) value composed of 14 genes in incremental feature selection (IFS) analysis was identified as the best AD classifier. As analyzed, the 14 genes played a pivotal role in determination of AD and may be core genes associated with the pathogenesis of AD. Finally, protein-protein interaction (PPI) network and Random Walk with Restart (RWR) analysis were applied to obtain core gene-associated genes, and key pathways related to AD were further analyzed. Overall, this study contributed to a deeper understanding of AD pathogenesis and provided theoretical guidance for related research and experiments.
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Affiliation(s)
- Longxiu Yang
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yuan Qin
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chongdong Jian
- Department of Neurology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
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5
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Mitra S, Bagchi A, Dasgupta R. Elucidation of Diverse Physico-Chemical Parameters in Mammalian Small Heat Shock Proteins: A Comprehensive Classification and Structural and Functional Exploration Using In Silico Approach. Appl Biochem Biotechnol 2021; 193:1836-1852. [PMID: 33570730 DOI: 10.1007/s12010-021-03497-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/07/2021] [Indexed: 02/06/2023]
Abstract
Small heat shock proteins (sHSPs), often known as molecular chaperones, are most prevalent in nature. Under certain stress-induced conditions, these sHSPs act as an ATP-independent variation and thus prevent the inactivation of various non-native substrate proteins and their aggregation. They also assist other ATP-dependent chaperones in the refolding of these substrates. In the case of prokaryotes and lower eukaryotes, the chaperone functions of sHSPs can bind a wide range of cellular proteins but preferentially protect translation-related proteins and metabolic enzymes. Eukaryotes usually encode a larger number of sHSPs than those of prokaryotes. The chaperone functions of mammalian sHSPs are regulated by phosphorylation in cells and also by temperature. Their sHSPs have different sub-cellular compartments and cell/tissue specificity. The substrate proteins of mammalian sHSPs or eukaryotic sHSPs accordingly reflect their multi-cellular complexity. The sHSPs of animals play roles in different physiological processes as cell differentiation, apoptosis, and longevity. In this work, the characterization, location, tissue specificity, and functional diversity of sHSPs from seven different mammalian species with special emphasis on humans have been studied. Through this extensive work, a novel and significant attempt have been made to classify them based on their omnipresence, tissue specificity, localization, secondary structure, probable mutations, and evolutionary significance.
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Affiliation(s)
- Sangeeta Mitra
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, West Bengal, 741235, India
| | - Angshuman Bagchi
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, West Bengal, 741235, India.
| | - Rakhi Dasgupta
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, West Bengal, 741235, India.
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6
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Collier MP, Benesch JLP. Small heat-shock proteins and their role in mechanical stress. Cell Stress Chaperones 2020; 25:601-613. [PMID: 32253742 PMCID: PMC7332611 DOI: 10.1007/s12192-020-01095-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2020] [Indexed: 12/13/2022] Open
Abstract
The ability of cells to respond to stress is central to health. Stress can damage folded proteins, which are vulnerable to even minor changes in cellular conditions. To maintain proteostasis, cells have developed an intricate network in which molecular chaperones are key players. The small heat-shock proteins (sHSPs) are a widespread family of molecular chaperones, and some sHSPs are prominent in muscle, where cells and proteins must withstand high levels of applied force. sHSPs have long been thought to act as general interceptors of protein aggregation. However, evidence is accumulating that points to a more specific role for sHSPs in protecting proteins from mechanical stress. Here, we briefly introduce the sHSPs and outline the evidence for their role in responses to mechanical stress. We suggest that sHSPs interact with mechanosensitive proteins to regulate physiological extension and contraction cycles. It is likely that further study of these interactions - enabled by the development of experimental methodologies that allow protein contacts to be studied under the application of mechanical force - will expand our understanding of the activity and functions of sHSPs, and of the roles played by chaperones in general.
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Affiliation(s)
- Miranda P Collier
- Department of Biology, Stanford University, 318 Campus Drive, Stanford, CA, 94305, USA
| | - Justin L P Benesch
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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7
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Neuromuscular Diseases Due to Chaperone Mutations: A Review and Some New Results. Int J Mol Sci 2020; 21:ijms21041409. [PMID: 32093037 PMCID: PMC7073051 DOI: 10.3390/ijms21041409] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle and the nervous system depend on efficient protein quality control, and they express chaperones and cochaperones at high levels to maintain protein homeostasis. Mutations in many of these proteins cause neuromuscular diseases, myopathies, and hereditary motor and sensorimotor neuropathies. In this review, we cover mutations in DNAJB6, DNAJB2, αB-crystallin (CRYAB, HSPB5), HSPB1, HSPB3, HSPB8, and BAG3, and discuss the molecular mechanisms by which they cause neuromuscular disease. In addition, previously unpublished results are presented, showing downstream effects of BAG3 p.P209L on DNAJB6 turnover and localization.
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8
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Kalioraki MA, Artemaki PI, Sklirou AD, Kontos CK, Adamopoulos PG, Papadopoulos IN, Trougakos IP, Scorilas A. Heat shock protein beta 3 (HSPB3) is an unfavorable molecular biomarker in colorectal adenocarcinoma. Mol Carcinog 2019; 59:116-125. [PMID: 31709619 DOI: 10.1002/mc.23133] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 01/05/2023]
Abstract
Small heat shock proteins (sHSPs) participate in numerous cellular functions including cell signaling, differentiation, and apoptosis. Deregulation of the physiological expression level of sHSPs has been associated with several malignancies. Heat shock protein beta 3 (HSPB3) is the third member of the sHSP family in human and is mainly expressed in skeletal and smooth muscles. In this study, we investigated the potential prognostic significance of HSPB3 expression in colorectal adenocarcinoma, the most frequent type of colorectal cancer. For this purpose, we isolated total RNA from 188 colorectal adenocarcinoma specimens and 68 paired noncancerous ones. After reverse transcription of 2 μg total RNA, we quantified HSPB3 levels by using an in-house-developed real-time quantitative polymerase chain reaction method, based on the SYBR Green chemistry. Comparison of HSPB3 levels among 68 pairs of colorectal tumors and their adjacent noncancerous mucosae uncovered the downregulation of HSPB3 expression in the majority of malignant colorectal tumors. More importantly, high HSPB3 expression is associated with poor relapse-free survival (RFS) and overall survival (OS) of patients with colorectal adenocarcinoma. Multivariable Cox regression analysis revealed that HSPB3 overexpression could serve as an adverse prognostic biomarker in colorectal adenocarcinoma, independent of tumor location, histological grade, and TNM stage. Patients' stratification according to tumor location, histological grade, and TNM stage revealed that high HSPB3 messenger RNA expression retains its unfavorable prognostic potential regarding OS, in particular groups of patients with substantially different prognosis. In conclusion, high HSPB3 expression is associated with poor RFS and OS of patients with colorectal adenocarcioma, independently of clinicopathological prognosticators.
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Affiliation(s)
- Maria-Anna Kalioraki
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Pinelopi I Artemaki
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Aimilia D Sklirou
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Christos K Kontos
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis G Adamopoulos
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Ioannis P Trougakos
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Andreas Scorilas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
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Nam DE, Nam SH, Lee AJ, Hong YB, Choi BO, Chung KW. Small heat shock protein B3 (HSPB3) mutation in an axonal Charcot-Marie-Tooth disease family. J Peripher Nerv Syst 2018; 23:60-66. [PMID: 29341343 DOI: 10.1111/jns.12249] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/11/2018] [Accepted: 01/11/2018] [Indexed: 12/11/2022]
Abstract
Heat shock protein B3 (HSPB3) gene encodes a small heat-shock protein 27-like protein which has a high sequence homology with HSPB1. A mutation in the HSPB3 was reported as the putative underlying cause of distal hereditary motor neuropathy 2C (dHMN2C) in 2010. We identified a heterozygous mutation (c.352T>C, p.Tyr118His) in the HSPB3 from a Charcot-Marie-Tooth disease type 2 (CMT2) family by the method of targeted next generation sequencing. The mutation was located in the well conserved alpha-crystalline domain, and several in silico predictions indicated a pathogenic effect of the mutation. Clinical and electrophysiological features of the patients indicated the axonal type of CMT. Clinical symptoms without sensory involvements were similar between the present family and the previous family. Mutations in the HSPB1 and HSPB8 genes have been reported to be relevant with both types of CMT2 and dHMN. Our findings will help in the molecular diagnosis of CMT2 by expanding the phenotypic range due to the HSPB3 mutations.
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Affiliation(s)
- Da E Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Soo H Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea.,Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Ah J Lee
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Young B Hong
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki W Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
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10
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Structural Aspects and Chaperone Activity of Human HspB3: Role of the “C-Terminal Extension”. Cell Biochem Biophys 2012; 64:61-72. [DOI: 10.1007/s12013-012-9366-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Ghayour-Mobarhan M, Saber H, Ferns GAA. The potential role of heat shock protein 27 in cardiovascular disease. Clin Chim Acta 2011; 413:15-24. [PMID: 21514288 DOI: 10.1016/j.cca.2011.04.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 04/03/2011] [Accepted: 04/05/2011] [Indexed: 12/13/2022]
Abstract
Heat shock proteins (Hsps) comprise several families of proteins expressed by a number of cell types following exposure to stressful environmental conditions that include heat, free radicals, toxins and ischemia, and are particularly involved in the recognition and renaturation of mis-folded proteins. Heat shock protein-27 (Hsp27) is a member of the small Hsp (sHsp) family with a molecular weight of approximately 27 KDa. In addition to its chaperoning functions, Hsp27 also appears to be involved in a diverse range of cellular functions, promoting cell survival through effects on the apoptotic pathway and plays important roles in cytoskeleton dynamics, cell differentiation and embryogenesis. Over the past two decades there has been an increasing interest in the relationship between Hsp27 and cardiovascular disease. Hsp27 is thought to exert an important role in the atherosclerotic process. Serum Hsp27 concentrations appear to be a biomarker of myocardial ischemia. In this review, we will focus on the possible protective and immuno-modulatory roles of Hsp27 in atherogenesis with special emphasis on their changes following acute coronary events and their potential as diagnostic and therapeutic targets.
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Affiliation(s)
- Majid Ghayour-Mobarhan
- Biochemistry and Nutrition Research Center and Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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12
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Kühlberg A, Haid M, Metzger S. Characterization of O-phosphohydroxyproline in rat {alpha}-crystallin A. J Biol Chem 2010; 285:31484-90. [PMID: 20682783 DOI: 10.1074/jbc.m109.035428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Post-translational modifications have major importance for the structure and function of a multiplicity of proteins. Phosphorylation is a widespread phenomenon among eukaryotic proteins. Whereas O-phosphorylation on the side chains of serine, threonine, and tyrosine in proteins is well known and has been studied extensively, to our knowledge the endogenous phosphorylation of hydroxyproline has not previously been reported. In the present work, we provide evidence for the first time that O-phosphohydroxyproline (Hyp(P)) is a proteinogenic amino acid. To detect Hyp(P) in proteins we generated a Hyp(P)-specific polyclonal antibody. We could identify Hyp(P) in various proteins by Western blot analysis, and we characterized the sequence position of Hyp(P) in the protein α-crystallin A by electrospray ionization-tandem mass spectrometry. Our experiments clearly demonstrate hydroxylation and subsequent phosphorylation of a proline residue in α-crystallin A in the eye as well as in heart tissue of rat.
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Affiliation(s)
- Axel Kühlberg
- Biological Medical Research Center, Heinrich-Heine-University of Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
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13
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Zhu Y, Zhu J, Wan X, Zhu Y, Zhang T. Gene expression of sHsps, Hsp40 and Hsp60 families in normal and abnormal embryonic development of mouse forelimbs. Toxicol Lett 2010; 193:242-51. [DOI: 10.1016/j.toxlet.2010.01.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 11/25/2022]
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den Engelsman J, Boros S, Dankers PY, Kamps B, Vree Egberts WT, Böde CS, Lane LA, Aquilina JA, Benesch JL, Robinson CV, de Jong WW, Boelens WC. The Small Heat-Shock Proteins HSPB2 and HSPB3 Form Well-defined Heterooligomers in a Unique 3 to 1 Subunit Ratio. J Mol Biol 2009; 393:1022-32. [DOI: 10.1016/j.jmb.2009.08.052] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 08/21/2009] [Accepted: 08/21/2009] [Indexed: 10/20/2022]
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15
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Morris AM, Treweek TM, Aquilina JA, Carver JA, Walker MJ. Glutamic acid residues in the C-terminal extension of small heat shock protein 25 are critical for structural and functional integrity. FEBS J 2009; 275:5885-98. [PMID: 19021764 DOI: 10.1111/j.1742-4658.2008.06719.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Small heat shock proteins (sHsps) are intracellular molecular chaperones that prevent the aggregation and precipitation of partially folded and destabilized proteins. sHsps comprise an evolutionarily conserved region of 80-100 amino acids, denoted the alpha-crystallin domain, which is flanked by regions of variable sequence and length: the N-terminal domain and the C-terminal extension. Although the two domains are known to be involved in the organization of the quaternary structure of sHsps and interaction with their target proteins, the role of the C-terminal extension is enigmatic. Despite the lack of sequence similarity, the C-terminal extension of mammalian sHsps is typically a short, polar segment which is unstructured and highly flexible and protrudes from the oligomeric structure. Both the polarity and flexibility of the C-terminal extension are important for the maintenance of sHsp solubility and for complexation with its target protein. In this study, mutants of murine Hsp25 were prepared in which the glutamic acid residues in the C-terminal extension at positions 190, 199 and 204 were each replaced with alanine. The mutants were found to be structurally altered and functionally impaired. Although there were no significant differences in the environment of tryptophan residues in the N-terminal domain or in the overall secondary structure, an increase in exposed hydrophobicity was observed for the mutants compared with wild-type Hsp25. The average molecular masses of the E199A and E204A mutants were comparable with that of the wild-type protein, whereas the E190A mutant was marginally smaller. All mutants displayed markedly reduced thermostability and chaperone activity compared with the wild-type. It is concluded that each of the glutamic acid residues in the C-terminal extension is important for Hsp25 to act as an effective molecular chaperone.
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Affiliation(s)
- Amie M Morris
- School of Biological Sciences, University of Wollongong, Australia
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16
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Hu Z, Yang B, Lu W, Zhou W, Zeng L, Li T, Wang X. HSPB2/MKBP, a novel and unique member of the small heat-shock protein family. J Neurosci Res 2008; 86:2125-33. [PMID: 18615620 DOI: 10.1002/jnr.21682] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although proteins belonging to the sHSP superfamily are diverse in sequence and size, most share characteristic features, including 1) a small molecular mass of 12-43 kDa, 2) a conserved alpha-crystallin domain of 80-100 residues, 3) formation of large oligomers, 4) a dynamic quaternary structure, and 5) induction by stress conditions and chaperone activity in suppressing protein aggregation. HSPB2/MKBP (myotonic dystrophy kinase-bind-protein) retains the structural motif of the alpha-crystallin family of HSPs but shows a unique nature compared with canonical family members, characterized by gene allocation, specific binding partners in skeletal muscle, and unique stress responsiveness. MKBP may be involved in the pathogenesis of myotonic dystrophy and contribute to the neuropathology in both Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis, Dutch type.
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Affiliation(s)
- Zhiping Hu
- Department of Neurology, The Second Xiangya Hospital, Central South University, Changsha, China
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17
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Hof D, Hoeke MO, Raats JMH. Multiple-antigen immunization of chickens facilitates the generation of recombinant antibodies to autoantigens. Clin Exp Immunol 2007; 151:367-77. [PMID: 18062792 DOI: 10.1111/j.1365-2249.2007.03569.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Antibody phage display is a powerful tool for the generation of monoclonal antibodies against virtually any given antigen. Chickens are phylogenetically more distant from humans compared to other laboratory animals, such as mice and rats. Therefore, the use of chickens is especially beneficial when generating recombinant antibodies against human autoantigens, which are often highly conserved among mammals. Another advantage of using chickens in antibody phage display is that the preparation of single chain variable fragment (scFv) antibody libraries is faster and easier compared to preparing such libraries from other species, as only two primer sets are needed for amplification of the chicken variable heavy chain (V(H)) and variable light chain (V(L)) genes. In the present study we explored the possibility to immunize chickens with antigen cocktails for the generation of recombinant antibody fragments directed to a range of human autoantigens. Two pairs of chickens were immunized with two cocktails of seven recombinant autoantigenic proteins, libraries were prepared and panned on the individual proteins. The polyclonal chicken sera reacted strongly with most of the antigens used for immunization. By creating and screening single-chain variable fragment antibody phage display libraries, recombinant monoclonal antibody fragments were isolated successfully against the autoantigens annexin XI, centromere protein B, heat shock protein B3, DNA topoisomerase I, histidyl tRNA synthetase, Ro52, Ro60, Rpp30 and U1A. In conclusion, the immunization of only four chickens with two distinct pools of a total of 14 autoantigenic proteins allowed the isolation of scFvs against nine of these antigens.
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Affiliation(s)
- D Hof
- Department of Biomolecular Chemistry 271, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
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18
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Fontaine JM, Sun X, Benndorf R, Welsh MJ. Interactions of HSP22 (HSPB8) with HSP20, αB-crystallin, and HSPB3. Biochem Biophys Res Commun 2005; 337:1006-11. [PMID: 16225851 DOI: 10.1016/j.bbrc.2005.09.148] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
Seven of the 10 mammalian small heat shock proteins (sHSP) are expressed in muscle where they constitute 3% or more of total protein. sHSPs interact with one another, and these interactions are believed to be important for their functions. In cell types expressing multiple sHSPs, it is of interest to know which sHSPs interact with one another. We have previously shown that HSP22 interacts with itself as well as with HSP27, MKBP, and cvHSP. Using yeast two-hybrid assays and Förster resonance energy transfer microscopy, we now show that HSP22 also can interact with two additional members of the sHSP family, alphaB-crystallin and HSP20. We also show that HSP22 is found in HPLC fractions of primate cardiac muscle containing high molecular weight complexes that include alphaB-crystallin and HSP20. Our results suggest that a variety of oligomers composed of different proportions of different sHSPs may form in cell types expressing multiple sHSPs.
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Affiliation(s)
- Jean-Marc Fontaine
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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19
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Ferrer E, González LM, Foster-Cuevas M, Cortéz MM, Dávila I, Rodríguez M, Sciutto E, Harrison LJS, Parkhouse RME, Gárate T. Taenia solium: characterization of a small heat shock protein (Tsol-sHSP35.6) and its possible relevance to the diagnosis and pathogenesis of neurocysticercosis. Exp Parasitol 2005; 110:1-11. [PMID: 15884156 DOI: 10.1016/j.exppara.2004.11.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A cDNA encoding for a predicted small heat shock protein (sHSP), Tsol-sfISP35.6, has been isolated by antibody screening of a Taenia solium c-DNA library. The clone was a full-length sequence (1172 bp) with an open reading frame of 945 bp and encoded for a 314 amino acid protein with deduced molecular mass of 35.6 kDa, isoelectric point of 5.6 arid the characteristic HSP20/alpha-crystallin domain duplicated. It was highly conserved, with a high sequence similarity with other platyhelminth sHSPs. Western blot analysis, using serum from neurocysticercosis patients (NCC), indicated that the purified Tsol-sHSP35.6 expression product was immunogenic, while in indirect ELISA, using the purified Tsol-sHSP35.6 expression product as antigen and serum samples from pigs and humans, 80% of T. solium infected pigs and 84% of patients with active, or 71% of patients with inactive NCC were sero-positive. The possible relevance of Tsol-sHSP35.6 in the diagnosis and pathogenesis of NCC is discussed.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Helminth/blood
- Antibodies, Helminth/immunology
- Antigens, Helminth/chemistry
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Base Sequence
- Blotting, Western
- DNA, Complementary/chemistry
- DNA, Complementary/isolation & purification
- Electrophoresis, Polyacrylamide Gel
- Enzyme-Linked Immunosorbent Assay
- Heat-Shock Proteins/chemistry
- Heat-Shock Proteins/genetics
- Heat-Shock Proteins/immunology
- Humans
- Immune Sera/immunology
- Isoelectric Point
- Molecular Sequence Data
- Molecular Weight
- Neurocysticercosis/diagnosis
- Neurocysticercosis/parasitology
- Open Reading Frames/genetics
- Rabbits
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Sensitivity and Specificity
- Sequence Alignment
- Sequence Homology, Amino Acid
- Swine
- Taenia solium/chemistry
- Taenia solium/genetics
- Taenia solium/immunology
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Affiliation(s)
- Elizabeth Ferrer
- Instituto de Salud Carlos III, Centro Nacional de Microbiología, Majadahonda, Madrid, Spain
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20
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Golenhofen N, Perng MD, Quinlan RA, Drenckhahn D. Comparison of the small heat shock proteins alphaB-crystallin, MKBP, HSP25, HSP20, and cvHSP in heart and skeletal muscle. Histochem Cell Biol 2004; 122:415-25. [PMID: 15480735 DOI: 10.1007/s00418-004-0711-z] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2004] [Indexed: 01/23/2023]
Abstract
Seven members of the small heat shock protein (sHSP) family are exceptional with respect to their constitutive high abundance in muscle tissue. It has been suggested that sHSPs displaying chaperone-like properties may stabilize myofibrillar proteins during stress conditions and prevent them from loss of function. In the present study five sHSPs (alphaB-crystallin, MKBP, HSP25, HSP20, and cvHSP) were investigated with respect to similarities and differences of their expression in heart and skeletal muscle under normal and ischemic conditions. In ischemic heart and skeletal muscle these five sHSPs translocated from cytosol to the Z-/I-area of myofibrils. Myofibrillar binding of all sHSPs was very tight and resisted for the most part extraction with 1 M NaSCN or 1 M urea. MKBP and HSP20 became extracted by 1 M NaSCN to a significant extent indicating that these two sHSPs may bind partially to actin-associated proteins which were completely extracted by this treatment. Ultrastructural localization of alphaB-crystallin showed diffuse distribution of immunogold label throughout the entire I-band in skeletal muscle fibers whereas in cardiomyocytes alphaB-crystallin was preferentially located at the N-line position of the I-band. These observations indicate different myofibrillar binding sites of alphaB-crystallin in cardiomyocytes versus skeletal muscle fibers. Further differences of the properties of sHSPs could be observed regarding fiber type distribution of sHSPs. Thus sHSPs form a complex stress-response system in striated muscle tissue with some common as well as some distinct functions in different muscle types.
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Affiliation(s)
- Nikola Golenhofen
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstrasse 6, 97070, Würzburg, Germany.
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21
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Katoh Y, Fujimoto M, Nakamura K, Inouye S, Sugahara K, Izu H, Nakai A. Hsp25, a member of the Hsp30 family, promotes inclusion formation in response to stress. FEBS Lett 2004; 565:28-32. [PMID: 15135047 DOI: 10.1016/j.febslet.2003.12.085] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Accepted: 12/23/2003] [Indexed: 11/28/2022]
Abstract
Protein aggregates are oligomeric complexes of misfolded proteins, and serve as the seeds of inclusion bodies termed aggresomes in the cells. Heat shock proteins (Hsps) prevent misfolding and aggregate formation. Here, we found that only avian Hsp25 dominantly accumulated in the aggresomes induced by proteasome inhibition. Molecular cloning of chicken Hsp25 (cHsp25) revealed that it belongs to the Hsp30 family, which is a subfamily of the alpha-crystallin/small Hsp gene family. Unexpectedly, overexpression of cHsp25 into HeLa cells promoted inclusion formation whereas overexpression of mouse Hsp27 and its chicken homologue did not. These results suggest that cHsp25 acts differently from other small Hsps on protein aggregates.
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Affiliation(s)
- Yumiko Katoh
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Minami-Kogushi 1-1-1, Ube 775-8505, Japan
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22
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Bhat SP. Crystallins, genes and cataract. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; 60:205-62. [PMID: 12790344 DOI: 10.1007/978-3-0348-8012-1_7] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Far from being a physical entity, assembled of inanimate structural proteins, the ocular lens epitomizes the biological ingenuity that sustains an essential and near-perfect physical system of immaculate optics. Crystallins (alpha, beta, and gamma) provide transparency by dint of their high concentration, but it is debatable whether proteins that provide transparency are any different, biologically or structurally, from those that are present in non-transparent structures or tissues. It is becoming increasingly clear that crystallins may have a plethora of metabolic and regulatory functions, both within the lens as well as outside of it. Alpha-crystallins are members of a small heat shock family of proteins and beta/gamma-crystallins belong to the family of epidermis-specific differentiation proteins. Crystallin gene expression has been studied from the perspective of the lens specificity of their promoters. Mutations in alpha-, beta-, and gamma-crystallins are linked with the phenotype of the loss of transparency. Understanding catalytic, non-structural properties of crystallins may be critical for understanding the malfunction in molecular cascades that lead to cataractogenesis and its eventual therapeutic amelioration.
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Affiliation(s)
- Suraj P Bhat
- Jules Stein Eye Institute and Brain Research Institute, Geffen School of Medicine at UCLA, Los Angeles, CA 90077-7000, USA.
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23
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van Rijk AE, Stege GJJ, Bennink EJ, May A, Bloemendal H. Nuclear staining for the small heat shock protein alphaB-crystallin colocalizes with splicing factor SC35. Eur J Cell Biol 2003; 82:361-8. [PMID: 12924631 DOI: 10.1078/0171-9335-00321] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
AlphaB-Crystallin has for a long time been considered a specific eye lens protein. Later on it appeared that this protein belongs to the family of the small heat shock proteins and that it occurs also extra-lenticularly in many different cell types. AlphaB-Crystallin is mainly present in the cytoplasm, but there are some indications that it might have a function in the nucleus too. However, till now its presence in the nucleus is uncertain. We therefore compared the localization of alphaB-crystallin in nine cell lines cultured under normal conditions using four different antisera. All four antisera gave a diffuse staining for alphaB-crystallin in the cytoplasm, but one of the antibodies consistently showed nuclear staining in eight of the cell types, in the form of distinct speckles. These speckles are equally pronounced in the different cell types, whether or not cytoplasmic alphaB-crystallin is present. Preabsorption of the antiserum with alphaB-crystallin abolished the staining. Furthermore we demonstrate that if only minor amounts of alphaB-crystallin are present, the protein seems to be located exclusively in the nucleus. However, in case of higher amounts of protein, alphaB-crystallin is distributed between cytoplasm and nucleus. The nuclear alphaB-crystallin exists, like the cytoplasmic alphaB-crystallin, in non-phosphorylated and phosphorylated forms, is Triton-insoluble but can be extracted by 2 M NaCl. These data suggest that alphaB-crystallin might be bound to the nuclear matrix per se or to nuclear matrix proteins via other proteins. In agreement with other nuclear matrix proteins, nuclear alphaB-crystallin staining turns diffuse upon mitosis and leaves the chromosomes unstained. Double staining experiments revealed colocalization of alphaB-crystallin with the splicing factor SC35 in nuclear speckles, suggesting a role for alphaB-crystallin in splicing or protection of the splicing machinery.
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Affiliation(s)
- Anke E van Rijk
- Department of Biochemistry, Faculty of Science, University of Nijmegen, Nijmegen, The Netherlands
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24
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Fontaine JM, Rest JS, Welsh MJ, Benndorf R. The sperm outer dense fiber protein is the 10th member of the superfamily of mammalian small stress proteins. Cell Stress Chaperones 2003; 8:62-9. [PMID: 12820655 PMCID: PMC514854 DOI: 10.1379/1466-1268(2003)8<62:tsodfp>2.0.co;2] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Nine proteins have been assigned to date to the superfamily of mammalian small heat shock proteins (sHsps): Hsp27 (HspB1, Hsp25), myotonic dystrophy protein kinase-binding protein (MKBP) (HspB2), HspB3, alphaA-crystallin (HspB4), alphaB-crystallin (HspB5), Hsp20 (p20, HspB6), cardiovascular heat shock protein (cvHsp [HspB7]), Hsp22 (HspB8), and HspB9. The most pronounced structural feature of sHsps is the alpha-crystallin domain, a conserved stretch of approximately 80 amino acid residues in the C-terminal half of the molecule. Using the alpha-crystallin domain of human Hsp27 as query in a BLAST search, we found sequence similarity with another mammalian protein, the sperm outer dense fiber protein (ODFP). ODFP occurs exclusively in the axoneme of sperm cells. Multiple alignment of human ODFP with the other human sHsps reveals that the primary structure of ODFP fits into the sequence pattern that is typical for this protein superfamily: alpha-crystallin domain (conserved), N-terminal domain (less conserved), central region (variable), and C-terminal tails (variable). In a phylogenetic analysis of 167 proteins of the sHsp superfamily, using Bayesian inference, mammalian ODFPs form a clade and are nested within previously identified sHsps, some of which have been implicated in cytoskeletal functions. Both the multiple alignment and the phylogeny suggest that ODFP is the 10th member of the superfamily of mammalian sHsps, and we propose to name it HspB10 in analogy with the other sHsps. The C-terminal tail of HspB10 has a remarkable low-complexity structure consisting of 10 repeats of the motif C-X-P. A BLAST search using the C-terminal tail as query revealed similarity with sequence elements in a number of Drosophila male sperm proteins, and mammalian type I keratins and cornifin-alpha. Taken together, the following findings suggest a specialized role of HspB10 in cytoskeleton: (1) the exclusive location in sperm cell tails, (2) the phylogenetic relationship with sHsps implicated in cytoskeletal functions, and (3) the partial similarity with cytoskeletal proteins.
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Affiliation(s)
- Jean-Marc Fontaine
- Department of Cell and Developmental Biology, Medical School, University of Michigan, 1335 Catherine Street, Ann Arbor, MI 48109-0616, USA
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25
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Gaestel M. sHsp-phosphorylation: enzymes, signaling pathways and functional implications. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2002; 28:151-69. [PMID: 11908057 DOI: 10.1007/978-3-642-56348-5_8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- M Gaestel
- Institut für Pharmazeutische Biologie, Martin-Luther-Universität Halle/Wittenberg, Hoher Weg 8, 06120 Halle, Germany
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26
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Davidson SM, Loones MT, Duverger O, Morange M. The developmental expression of small HSP. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2002; 28:103-28. [PMID: 11908055 DOI: 10.1007/978-3-642-56348-5_6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Sean M Davidson
- Unité de Génétique Moléculaire, Ecole normale supérieure, 46 rue d'Ulm, 75230 Paris, France
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27
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Van Montfort R, Slingsby C, Vierling E. Structure and function of the small heat shock protein/alpha-crystallin family of molecular chaperones. ADVANCES IN PROTEIN CHEMISTRY 2002; 59:105-56. [PMID: 11868270 DOI: 10.1016/s0065-3233(01)59004-x] [Citation(s) in RCA: 300] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- R Van Montfort
- Department of Crystallography, Birkbeck College, Malet Street, London WC1E 7HX, United Kingdom
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28
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Verschuure P, Croes Y, van den IJssel PRLA, Quinlan RA, de Jong WW, Boelens WC. Translocation of small heat shock proteins to the actin cytoskeleton upon proteasomal inhibition. J Mol Cell Cardiol 2002; 34:117-28. [PMID: 11851352 DOI: 10.1006/jmcc.2001.1493] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of small heat shock proteins (sHsps) as molecular chaperones is still poorly understood. We therefore investigated the effect of proteasomal inhibition on sHsps in the rat cardiac myoblast cell line H9c2. Proteasomes are responsible for controlled degradation of intracellular proteins. Inhibition of their activities leads to accumulation of unfolded proteins, which can form insoluble "aggresomes" together with proteasomes and heat shock proteins Hsp70 and Hsp90. We here report that upon proteasome inhibition, alpha B-crystallin and Hsp25 translocate from the detergent-soluble cytosolic fraction to the detergent-insoluble nuclear/cytoskeletal fraction. Although phosphorylation of both alpha B-crystallin and Hsp25 is induced, this does not seem to be essential for the translocation. Immunocytochemistry revealed that alpha B-crystallin and Hsp25, which show a diffuse cytoplasmic staining in unstressed H9c2 cells, colocalize with F-actin upon proteasomal inhibition. After transfection in H9c2 cells, other sHsps (alpha A-crystallin, Hsp20, HspB2 and HspB3) showed similar translocation to the actin cytoskeleton. The redistribution of sHsps upon proteasomal inhibition may reflect a mechanism by which cells are protected from damaged intracellular proteins by sequestering them on the cytoskeleton.
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Affiliation(s)
- Pauline Verschuure
- Department of Biochemistry, Faculty of Science, University of Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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29
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Nakagawa M, Tsujimoto N, Nakagawa H, Iwaki T, Fukumaki Y, Iwaki A. Association of HSPB2, a member of the small heat shock protein family, with mitochondria. Exp Cell Res 2001; 271:161-8. [PMID: 11697892 DOI: 10.1006/excr.2001.5362] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously identified HSPB2, a new member of the small heat shock protein family, expressed in heart and skeletal muscles. In this study, we used a polyclonal anti-HSPB2 antibody and examined the subcellular localization of HSPB2 in differentiated C2C12 cells, KNS-81 cells, and NIH3T3 transfectants expressing human HSPB2. Double staining with anti-HSPB2 and various markers for cytoplasmic structures showed that HSPB2 was present in the cytosol as granules, some of which colocalized with mitochondria. This colocalization was not altered by a colchicine treatment, indicating that it is independent of microtubules. The subcellular fractionation of differentiated C2C12 cells revealed that HSPB2 was mainly detected in the postmitochondrial supernatant, but mild heat treatment enriched the amount of HSPB2 in the mitochondrial fraction. The expression of HSPB2 protected the cells from heat-induced cell death. In addition, Northern blot analysis revealed that expression of HSPB2 mRNA is higher in slow-twitch muscle than in fast-twitch muscle, which correlates with the amounts of mitochondria present in these two types of tissue. Taken together, these results suggest that HSPB2 may not localize in the matrix, but rather associates with the outer membrane components of the mitochondria and thus plays a role in the stress response.
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Affiliation(s)
- M Nakagawa
- Division of Disease Genes, Research Center for Genetic Information, Kyushu University, Fukuoka, 812-8582, Japan
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30
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Kappé G, Verschuure P, Philipsen RL, Staalduinen AA, Van de Boogaart P, Boelens WC, De Jong WW. Characterization of two novel human small heat shock proteins: protein kinase-related HspB8 and testis-specific HspB9. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1520:1-6. [PMID: 11470154 DOI: 10.1016/s0167-4781(01)00237-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Using search profiles based on the conserved alpha-crystallin domain that is characteristic for small heat shock proteins (sHsps), we traced two new human sHsps. One of these, being the eighth known human sHsp and thus named HspB8, was recently described as a serine-threonine protein kinase (H11), but not identified as an sHsp (C.C. Smith, Y.X. Yu, M. Kulka, L. Aurelian, J. Biol. Chem. 275 (2000)). Northern blotting showed that HspB8/H11 is predominantly transcribed in skeletal muscle and heart, like most other sHsps. The other, named HspB9, is specifically expressed in testis, notably in the spermatogenic cells from late pachytene spermatocyte stage till elongate spermatid stage. While mammalian sHsps are generally highly conserved, mouse HspB9 shows 38% sequence difference with human HspB9, which may confirm its sex-related role.
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Affiliation(s)
- G Kappé
- 161 Department of Biochemistry, Univeristy of Nijmegen, The Netherlands
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31
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Benndorf R, Sun X, Gilmont RR, Biederman KJ, Molloy MP, Goodmurphy CW, Cheng H, Andrews PC, Welsh MJ. HSP22, a new member of the small heat shock protein superfamily, interacts with mimic of phosphorylated HSP27 ((3D)HSP27). J Biol Chem 2001; 276:26753-61. [PMID: 11342557 DOI: 10.1074/jbc.m103001200] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most of the members of the superfamily of mammalian small heat shock or stress proteins are abundant in muscles where they play a role in muscle function and maintenance of muscle integrity. One member of this protein superfamily, human HSP27, is rapidly phosphorylated on three serine residues (Ser(15), Ser(78), and Ser(82)) during cellular response to a number of extracellular factors. To understand better the role of HSP27, we performed a yeast two-hybrid screen of a human heart cDNA library for HSP27-interacting proteins. By using the triple aspartate mutant, a mimic of phosphorylated HSP27, as "bait" construct, a protein with a molecular mass of 21.6 kDa was identified as an HSP27-binding protein. Sequence analysis revealed that this new protein shares an overall sequence identity of 33% with human HSP27. This protein also contains the alpha-crystallin domain in its C-terminal half, a hallmark of the superfamily of small stress proteins. Thus, the new protein itself is a member of this protein superfamily, and consequently we designated it HSP22. According to the two-hybrid data, HSP22 interacts preferentially with the triple aspartate form of HSP27 as compared with wild-type HSP27. HSP22 is expressed predominantly in muscles. In vitro, HSP22 is phosphorylated by protein kinase C (at residues Ser(14) and Thr(63)) and by p44 mitogen-activated protein kinase (at residues Ser(27) and Thr(87)) but not by MAPKAPK-2.
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Affiliation(s)
- R Benndorf
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
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Scharf KD, Siddique M, Vierling E. The expanding family of Arabidopsis thaliana small heat stress proteins and a new family of proteins containing alpha-crystallin domains (Acd proteins). Cell Stress Chaperones 2001; 6:225-37. [PMID: 11599564 PMCID: PMC434404 DOI: 10.1379/1466-1268(2001)006<0225:tefoat>2.0.co;2] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2001] [Accepted: 05/01/2001] [Indexed: 11/24/2022] Open
Abstract
Comprehensive analysis of the Arabidopsis genome revealed a total of 13 sHsps belonging to 6 classes defined on the basis of their intracellular localization and sequence relatedness plus 6 ORFs encoding proteins distantly related to the cytosolic class Cl or the plastidial class of sHsps. The complexity of the Arabidopsis sHsp family far exceeds that in any other organism investigated to date. Furthermore, we have identified a new family of ORFs encoding multidomain proteins that contain one or more regions with homology to the ACD (Acd proteins). The functions of the Acd proteins and the role of their ACDs remain to be investigated.
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Affiliation(s)
- K D Scharf
- Biocenter of the Goethe University, Frankfurt/Main, Germany.
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Favet N, Duverger O, Loones MT, Poliard A, Kellermann O, Morange M. Overexpression of murine small heat shock protein HSP25 interferes with chondrocyte differentiation and decreases cell adhesion. Cell Death Differ 2001; 8:603-13. [PMID: 11536011 DOI: 10.1038/sj.cdd.4400847] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2000] [Revised: 12/13/2000] [Accepted: 01/15/2001] [Indexed: 11/09/2022] Open
Abstract
Although multiple functions for the small heat shock protein HSP25 have been proposed, its specific role during developmental and differentiation processes is not known. Cartilage is one of the tissues in which HSP25 is specifically and highly expressed during development. C1 cells, able to form aggregates in vitro, can be induced to differentiate into chondrocytes. In this study, we generated two stable transfected clones overexpressing HSP25 at two different levels. Cell morphology and growth rate were modified in both clones, although the actin content and distribution did not seem to be altered. Overexpressing clones had more difficulties in coalescing, leading to smaller aggregates and they did not differentiate into chondrocytes. Subsequently, these aggregates tended to dissociate into loose masses of dying cells. The strength of all these effects was directly correlated to the level of HSP25 overexpression. These data suggest that overexpressing HSP25 decreases cellular adhesion and interferes with chondrocyte differentiation.
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Affiliation(s)
- N Favet
- Unité de Génétique Moléculaire, Ecole Normale Supérieure, 46, rue d'Ulm, 75230 Paris, Cedex 05, France
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van Rijk AF, van den Hurk MJ, Renkema W, Boelens WC, de Jong WW, Bloemendal H. Characteristics of super alphaA-crystallin, a product of in vitro exon shuffling. FEBS Lett 2000; 480:79-83. [PMID: 11034304 DOI: 10.1016/s0014-5793(00)01908-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
alphaA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super alphaA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super alphaA-crystallin, which is viable in a mouse skeletal muscle cell line, with normal alphaA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super alphaA-crystallin subunits exchange as readily between complexes as does normal alphaA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
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Affiliation(s)
- A F van Rijk
- Department of Biochemistry, University of Nijmegen, The Netherlands
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35
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Sugiyama Y, Suzuki A, Kishikawa M, Akutsu R, Hirose T, Waye MM, Tsui SK, Yoshida S, Ohno S. Muscle develops a specific form of small heat shock protein complex composed of MKBP/HSPB2 and HSPB3 during myogenic differentiation. J Biol Chem 2000; 275:1095-104. [PMID: 10625651 DOI: 10.1074/jbc.275.2.1095] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previously, we identified a new mammalian sHSP, MKBP, as a myotonic dystrophy protein kinase-binding protein, and suggested its important role in muscle maintenance (Suzuki, A., Sugiyama, Y., Hayashi, Y., Nyu-i, N., Yoshida, M., Nonaka, I., Ishiura, S., Arahata, K., and Ohno, S. (1998) J. Cell Biol. 140, 1113-1124). In this paper, we develop the former work by performing extensive characterization of five of the six sHSPs so far identified, that is, HSP27, alphaB-crystallin, p20, MKBP/HSPB2, and HSPB3, omitting lens-specific alphaA-crystallin. Tissue distribution analysis revealed that although each sHSP shows differential constitutive expression in restricted tissues, tissues that express all five sHSPs are only muscle-related tissues. Especially, the expressions of HSPB3, identified for the first time as a 17-kDa protein in this paper, and MKBP/HSPB2 are distinctly specific to muscles. Moreover, these sHSPs form an oligomeric complex with an apparent molecular mass of 150 kDa that is completely independent of the oligomers formed by HSP27, alphaB-crystallin, and p20. The expressions of MKBP/HSPB2 and HSPB3 are induced during muscle differentiation under the control of MyoD, suggesting that the sHSP oligomer comprising MKBP/HSPB2 and HSPB3 represents an additional system closely related to muscle function. The functional divergence among sHSPs in different oligomers is also demonstrated in several ways: 1) an interaction with myotonic dystrophy protein kinase, which has been suggested to be important for the maintenance of myofibril integrity, was observed only for MKBP/HSPB2; 2) a myotube-specific association with actin bundles was observed for HSP27 and alphaB-crystallin, but not for MKBP/HSPB2; and 3) sHSPs whose mRNAs are induced by heat shock are alphaB-crystallin and HSP27. Taken together, the results suggest that muscle cells develop two kinds of stress response systems composed of diverged sHSP members, and that these systems work independently in muscle maintenance and differentiation.
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Affiliation(s)
- Y Sugiyama
- Department of Molecular Biology, Yokohama City University School of Medicine, Kanazawa-ku, Yokohama 236-0004, Japan
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van de Klundert FA, de Jong WW. The small heat shock proteins Hsp20 and alphaB-crystallin in cultured cardiac myocytes: differences in cellular localization and solubilization after heat stress. Eur J Cell Biol 1999; 78:567-72. [PMID: 10494863 DOI: 10.1016/s0171-9335(99)80022-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hsp20, a recently described new member of the small heat shock protein superfamily, is abundant in heart, skeletal muscle types and smooth muscle. We investigated the intracellular localization of Hsp20 in cultured rat neonatal cardiac myocytes, under normal conditions and after stress. These cellular characteristics of Hsp20 were compared with those of its closest relative, alphaB-crystallin, which is also highly expressed in heart. Like alphaB-crystallin, Hsp20 is normally located in the cytoplasm of the cardiac myocytes. After a heat stress, a subpopulation of Hsp20 migrates into the nucleus, while another part remains in the cytoplasm. In very few cells a faint sarcomeric association of Hsp20 is observed. In contrast, as previously reported, alphaB-crystallin displays a very distinct cross-striated sarcomeric staining after the heat shock, but no nuclear migration. Also at the level of Triton solubility, differences exist between the two related proteins; while alphaB-crystallin, like other small heat shock proteins, becomes insoluble upon heat stress, Hsp20 remains largely soluble. Our results indicate that Hsp20 and alphaB-crystallin, despite their structural similarities, display conspicuous functional differences.
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Kawazoe Y, Tanabe M, Nakai A. Ubiquitous and cell-specific members of the avian small heat shock protein family. FEBS Lett 1999; 455:271-5. [PMID: 10437787 DOI: 10.1016/s0014-5793(99)00900-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small heat shock proteins (sHsps) have been suggested to act as molecular chaperones for many kinds of substrates and have protective roles in cells exposed to external stresses. Unlike other major Hsps such as Hsp70 and Hsp90, expression of many vertebrate sHsps is restricted to the muscle tissues and/or eye lens. Among the sHsps, the heat-inducible human Hsp27 (hHsp27) homologue is believed to be expressed ubiquitously in various cell types. Here, we distinguished the chicken homologue of hHsp27 (cHsp24) from the chicken major heat-inducible protein of molecular size 25 kDa (cHsp25). cHsp25 is not expressed in the absence of stress, but is highly expressed after hyperthermia in all tissues of developing embryos. In contrast, expression of cHsp24 is restricted to some specific tissues even in the presence of stress. Thus, cHsp25 is the first member of the sHsps in vertebrates the expression of which is ubiquitous in tissues exposed to external stresses similar to Hsp70.
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Affiliation(s)
- Y Kawazoe
- Department of Molecular and Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Japan
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Abstract
Undesired side products of DNA transfections are usually discarded. However, here, we show that such products may provide insight into mutational events that are also a major driving force in protein evolution. While studying the small heat-shock protein alphaA-crystallin, we transfected the hamster alphaA-crystallin gene into a mouse muscle cell line. One of the stable transfected cell lines expressed, in addition to the expected normal alphaA- and alternatively spliced alphaAins-crystallins, two slightly larger, immunologically cross-reacting proteins. These proteins were found to be encoded by a mutant alphaA-crystallin gene with a large intragenic duplication, arisen by illegitimate recombination at two CCCAT homologies, approximately 1.8 kilobases apart in the normal hamster alphaA-crystallin gene. As a consequence, a tandem-duplicated exon 3 sequence is present in the mature mRNA of this gene, resulting in a 41-residue repeat in the translated proteins. Cells expressing the elongated alphaA-crystallins have normal growth characteristics and the usual diffuse cytoplasmic distribution of immunoreactive alphaA-crystallin. Size-exclusion chromatography of cell extracts indicated that the mutant proteins are readily incorporated into the normal large water-soluble alphaA-crystallin complexes, showing that the insert does not disturb the integrity of these complexes. This viable alphaA-crystallin mutant thus mimics the origins and effects of exon duplication, which is a common consequence of exon shuffling in mammalian genome evolution.
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Affiliation(s)
- A A van Rijk
- Department of Biochemistry, University of Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Downs CA, Jones LR, Heckathorn SA. Evidence for a novel set of small heat-shock proteins that associates with the mitochondria of murine PC12 cells and protects NADH:ubiquinone oxidoreductase from heat and oxidative stress. Arch Biochem Biophys 1999; 365:344-50. [PMID: 10328830 DOI: 10.1006/abbi.1999.1177] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several previously unreported small heat-shock proteins (sHsps) were detected in mitochondria from heat-stressed rat PC12 cells, but not in unstressed controls. Functional inactivation of the mitochondrial sHsps with murine Hsp25 antibody indicated that these sHsps protect NADH:ubiquinone oxidoreductase and NADH dehydrogenase activity (i.e., complex I) in submitochondrial vesicles during heat and oxidative stress. These results (i) confirm the existence of multiple sHsps in mammals and indicate that several of these sHsps associate with the mitochondria, (ii) indicate a conserved function between plant and mammalian mitochondrial sHsps in protecting electron transport during stress, and (iii) suggest that these sHsps may play an important role in diseases whose etiology is based upon oxidative damage of complex I.
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Affiliation(s)
- C A Downs
- Department of Biology, Department of Physics, University of Charleston, 58 Coming Street, Charleston, South Carolina, 29424, USA.
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