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Mattei D, Ivanov A, Hammer J, Ugursu B, Schalbetter S, Richetto J, Weber-Stadlbauer U, Mueller F, Scarborough J, Wolf SA, Kettenmann H, Wollscheid B, Beule D, Meyer U. Microglia undergo molecular and functional adaptations to dark and light phases in male laboratory mice. Brain Behav Immun 2024; 120:571-583. [PMID: 38986723 DOI: 10.1016/j.bbi.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/20/2024] [Accepted: 07/06/2024] [Indexed: 07/12/2024] Open
Abstract
Microglia are increasingly recognized to contribute to brain health and disease. Preclinical studies using laboratory rodents are essential to advance our understanding of the physiological and pathophysiological roles of these cells in the central nervous system. Rodents are nocturnal animals, and they are mostly maintained in a defined light-dark cycle within animal facilities, with many laboratories investigating the molecular and functional profiles of microglia exclusively during the animals' light (sleep) phase. However, only a few studies have considered possible differences in microglial functions between the active and sleep phases. Based on initial evidence suggesting that microglial intrinsic clock genes can affect their phenotypes, we sought to investigate differences in transcriptional, proteotype and functional profiles of microglia between light (sleep) and dark (active) phases, and how these changes are affected in pathological models. We found marked transcriptional and proteotype differences between microglia harvested from male mice during the light or dark phase. Amongst others, these differences related to genes and proteins associated with immune responses, motility, and phagocytosis, which were reflected by functional alterations in microglial synaptic pruning and response to bacterial stimuli. Possibly accounting for such changes, we found RNA and protein regulation in SWI/SNF and NuRD chromatin remodeling complexes between light and dark phases. Importantly, we also show that the time of microglial sample collection influences the nature of microglial transcriptomic changes in a model of immune-mediated neurodevelopmental disorders. Our findings emphasize the importance of considering diurnal factors in studying microglial cells and indicate that implementing a circadian perspective is pivotal for advancing our understanding of their physiological and pathophysiological roles in brain health and disease.
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Affiliation(s)
- Daniele Mattei
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Nash Family Department of Neuroscience & Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America.
| | - Andranik Ivanov
- Core Unit Bioinformatics, Berlin Institute of Health, Charité-Universitätsmedizin, Berlin, Germany
| | - Jacqueline Hammer
- Institute of Molecular Systems Biology and Department for Health Sciences and Technology, ETH Zürich, Switzerland
| | - Bilge Ugursu
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany; Psychoneuroimmunology, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Sina Schalbetter
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Juliet Richetto
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Ulrike Weber-Stadlbauer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Flavia Mueller
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Joseph Scarborough
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland
| | - Susanne A Wolf
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Ophthalmology, Charité - Universitätsmedizin Berlin, Germany; Psychoneuroimmunology, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neuroscience, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bernd Wollscheid
- Institute of Molecular Systems Biology and Department for Health Sciences and Technology, ETH Zürich, Switzerland
| | - Dieter Beule
- Core Unit Bioinformatics, Berlin Institute of Health, Charité-Universitätsmedizin, Berlin, Germany
| | - Urs Meyer
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.
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Berg AE, Velayuthan LP, Månsson A, Ušaj M. Cost-Efficient Expression of Human Cardiac Myosin Heavy Chain in C2C12 Cells with a Non-Viral Transfection Reagent. Int J Mol Sci 2024; 25:6747. [PMID: 38928453 PMCID: PMC11203843 DOI: 10.3390/ijms25126747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Production of functional myosin heavy chain (MHC) of striated muscle myosin II for studies of isolated proteins requires mature muscle (e.g., C2C12) cells for expression. This is important both for fundamental studies of molecular mechanisms and for investigations of deleterious diseases like cardiomyopathies due to mutations in the MHC gene (MYH7). Generally, an adenovirus vector is used for transfection, but recently we demonstrated transfection by a non-viral polymer reagent, JetPrime. Due to the rather high costs of JetPrime and for the sustainability of the virus-free expression method, access to more than one transfection reagent is important. Here, we therefore evaluate such a candidate substance, GenJet. Using the human cardiac β-myosin heavy chain (β-MHC) as a model system, we found effective transfection of C2C12 cells showing a transfection efficiency nearly as good as with the JetPrime reagent. This was achieved following a protocol developed for JetPrime because a manufacturer-recommended application protocol for GenJet to transfect cells in suspension did not perform well. We demonstrate, using in vitro motility assays and single-molecule ATP turnover assays, that the protein expressed and purified from cells transfected with the GenJet reagent is functional. The purification yields reached were slightly lower than in JetPrime-based purifications, but they were achieved at a significantly lower cost. Our results demonstrate the sustainability of the virus-free method by showing that more than one polymer-based transfection reagent can generate useful amounts of active MHC. Particularly, we suggest that GenJet, due to its current ~4-fold lower cost, is useful for applications requiring larger amounts of a given MHC variant.
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Affiliation(s)
| | | | - Alf Månsson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, 391 82 Kalmar, Sweden; (A.E.B.); (L.P.V.)
| | - Marko Ušaj
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, 391 82 Kalmar, Sweden; (A.E.B.); (L.P.V.)
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Berg A, Velayuthan LP, Tågerud S, Ušaj M, Månsson A. Probing actin-activated ATP turnover kinetics of human cardiac myosin II by single molecule fluorescence. Cytoskeleton (Hoboken) 2024. [PMID: 38623952 DOI: 10.1002/cm.21858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/06/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024]
Abstract
Mechanistic insights into myosin II energy transduction in striated muscle in health and disease would benefit from functional studies of a wide range of point-mutants. This approach is, however, hampered by the slow turnaround of myosin II expression that usually relies on adenoviruses for gene transfer. A recently developed virus-free method is more time effective but would yield too small amounts of myosin for standard biochemical analyses. However, if the fluorescent adenosine triphosphate (ATP) and single molecule (sm) total internal reflection fluorescence microscopy previously used to analyze basal ATP turnover by myosin alone, can be expanded to actin-activated ATP turnover, it would appreciably reduce the required amount of myosin. To that end, we here describe zero-length cross-linking of human cardiac myosin II motor fragments (sub-fragment 1 long [S1L]) to surface-immobilized actin filaments in a configuration with maintained actin-activated ATP turnover. After optimizing the analysis of sm fluorescence events, we show that the amount of myosin produced from C2C12 cells in one 60 mm cell culture plate is sufficient to obtain both the basal myosin ATP turnover rate and the maximum actin-activated rate constant (kcat). Our analysis of many single binding events of fluorescent ATP to many S1L motor fragments revealed processes reflecting basal and actin-activated ATPase, but also a third exponential process consistent with non-specific ATP-binding outside the active site.
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Affiliation(s)
- Albin Berg
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Lok Priya Velayuthan
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Sven Tågerud
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Marko Ušaj
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Alf Månsson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
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4
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Zeng C, Han S, Pan Y, Huang Z, Zhang B, Zhang B. Revisiting the chaperonin T-complex protein-1 ring complex in human health and disease: A proteostasis modulator and beyond. Clin Transl Med 2024; 14:e1592. [PMID: 38363102 PMCID: PMC10870801 DOI: 10.1002/ctm2.1592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/28/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Disrupted protein homeostasis (proteostasis) has been demonstrated to facilitate the progression of various diseases. The cytosolic T-complex protein-1 ring complex (TRiC/CCT) was discovered to be a critical player in orchestrating proteostasis by folding eukaryotic proteins, guiding intracellular localisation and suppressing protein aggregation. Intensive investigations of TRiC/CCT in different fields have improved the understanding of its role and molecular mechanism in multiple physiological and pathological processes. MAIN BODY In this review, we embark on a journey through the dynamic protein folding cycle of TRiC/CCT, unraveling the intricate mechanisms of its substrate selection, recognition, and intriguing folding and assembly processes. In addition to discussing the critical role of TRiC/CCT in maintaining proteostasis, we detail its involvement in cell cycle regulation, apoptosis, autophagy, metabolic control, adaptive immunity and signal transduction processes. Furthermore, we meticulously catalogue a compendium of TRiC-associated diseases, such as neuropathies, cardiovascular diseases and various malignancies. Specifically, we report the roles and molecular mechanisms of TRiC/CCT in regulating cancer formation and progression. Finally, we discuss unresolved issues in TRiC/CCT research, highlighting the efforts required for translation to clinical applications, such as diagnosis and treatment. CONCLUSION This review aims to provide a comprehensive view of TRiC/CCT for researchers to inspire further investigations and explorations of potential translational possibilities.
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Affiliation(s)
- Chenglong Zeng
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Shenqi Han
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Yonglong Pan
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Zhao Huang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Binhao Zhang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
| | - Bixiang Zhang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Clinical Medical Research Center of Hepatic Surgery at Hubei ProvinceWuhanChina
- Hubei Key Laboratory of Hepato‐Pancreatic‐Biliary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Key Laboratory of Organ Transplantation, Ministry of EducationWuhanChina
- Key Laboratory of Organ Transplantation, National Health CommissionWuhanChina
- Key Laboratory of Organ Transplantation, Chinese Academy of Medical SciencesWuhanChina
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5
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Velayuthan LP, Moretto L, Tågerud S, Ušaj M, Månsson A. Virus-free transfection, transient expression, and purification of human cardiac myosin in mammalian muscle cells for biochemical and biophysical assays. Sci Rep 2023; 13:4101. [PMID: 36907906 PMCID: PMC10008826 DOI: 10.1038/s41598-023-30576-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/27/2023] [Indexed: 03/13/2023] Open
Abstract
Myosin expression and purification is important for mechanistic insights into normal function and mutation induced changes. The latter is particularly important for striated muscle myosin II where mutations cause several debilitating diseases. However, the heavy chain of this myosin is challenging to express and the standard protocol, using C2C12 cells, relies on viral infection. This is time and work intensive and associated with infrastructural demands and biological hazards, limiting widespread use and hampering fast generation of a wide range of mutations. We here develop a virus-free method to overcome these challenges. We use this system to transfect C2C12 cells with the motor domain of the human cardiac myosin heavy chain. After optimizing cell transfection, cultivation and harvesting conditions, we functionally characterized the expressed protein, co-purified with murine essential and regulatory light chains. The gliding velocity (1.5-1.7 µm/s; 25 °C) in the in vitro motility assay as well as maximum actin activated catalytic activity (kcat; 8-9 s-1) and actin concentration for half maximal activity (KATPase; 70-80 µM) were similar to those found previously using virus based infection. The results should allow new types of studies, e.g., screening of a wide range of mutations to be selected for further characterization.
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Affiliation(s)
- Lok Priya Velayuthan
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden
| | - Luisa Moretto
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden
| | - Sven Tågerud
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden
| | - Marko Ušaj
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden.
| | - Alf Månsson
- Department of Chemistry and Biomedical Sciences, Linnaeus University, 391 82, Kalmar, Sweden.
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6
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Odunuga OO, Oberhauser AF. Beyond Chaperoning: UCS Proteins Emerge as Regulators of Myosin-Mediated Cellular Processes. Subcell Biochem 2023; 101:189-211. [PMID: 36520308 DOI: 10.1007/978-3-031-14740-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The UCS (UNC-45/CRO1/She4p) family of proteins has emerged as chaperones specific for the folding, assembly, and function of myosin. UCS proteins participate in various myosin-dependent cellular processes including myofibril organization and muscle functions, cell differentiation, striated muscle development, cytokinesis, and endocytosis. Mutations in the genes that code for UCS proteins cause serious defects in myosin-dependent cellular processes. UCS proteins that contain an N-terminal tetratricopeptide repeat (TPR) domain are called UNC-45. Vertebrates usually possess two variants of UNC-45, the ubiquitous general-cell UNC-45 (UNC-45A) and the striated muscle UNC-45 (UNC-45B), which is exclusively expressed in skeletal and cardiac muscles. Except for the TPR domain in UNC-45, UCS proteins comprise of several irregular armadillo (ARM) repeats that are organized into a central domain, a neck region, and the canonical C-terminal UCS domain that functions as the chaperoning module. With or without TPR, UCS proteins form linear oligomers that serve as scaffolds that mediate myosin folding, organization into myofibrils, repair, and motility. This chapter reviews emerging functions of these proteins with a focus on UNC-45 as a dedicated chaperone for folding, assembly, and function of myosin at protein and potentially gene levels. Recent experimental evidences strongly support UNC-45 as an absolute regulator of myosin, with each domain of the chaperone playing different but complementary roles during the folding, assembly, and function of myosin, as well as recruiting Hsp90 as a co-chaperone to optimize key steps. It is becoming increasingly clear that UNC-45 also regulates the transcription of several genes involved in myosin-dependent cellular processes.
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Affiliation(s)
- Odutayo O Odunuga
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, Nacogdoches, TX, USA.
| | - Andres F Oberhauser
- Department of Neuroscience, Cell Biology, & Anatomy, The University of Texas Medical Branch, Galveston, TX, USA.
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7
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Ušaj M, Moretto L, Månsson A. Critical Evaluation of Current Hypotheses for the Pathogenesis of Hypertrophic Cardiomyopathy. Int J Mol Sci 2022; 23:2195. [PMID: 35216312 PMCID: PMC8880276 DOI: 10.3390/ijms23042195] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/07/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Hereditary hypertrophic cardiomyopathy (HCM), due to mutations in sarcomere proteins, occurs in more than 1/500 individuals and is the leading cause of sudden cardiac death in young people. The clinical course exhibits appreciable variability. However, typically, heart morphology and function are normal at birth, with pathological remodeling developing over years to decades, leading to a phenotype characterized by asymmetric ventricular hypertrophy, scattered fibrosis and myofibrillar/cellular disarray with ultimate mechanical heart failure and/or severe arrhythmias. The identity of the primary mutation-induced changes in sarcomere function and how they trigger debilitating remodeling are poorly understood. Support for the importance of mutation-induced hypercontractility, e.g., increased calcium sensitivity and/or increased power output, has been strengthened in recent years. However, other ideas that mutation-induced hypocontractility or non-uniformities with contractile instabilities, instead, constitute primary triggers cannot yet be discarded. Here, we review evidence for and criticism against the mentioned hypotheses. In this process, we find support for previous ideas that inefficient energy usage and a blunted Frank-Starling mechanism have central roles in pathogenesis, although presumably representing effects secondary to the primary mutation-induced changes. While first trying to reconcile apparently diverging evidence for the different hypotheses in one unified model, we also identify key remaining questions and suggest how experimental systems that are built around isolated primarily expressed proteins could be useful.
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Affiliation(s)
| | | | - Alf Månsson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, SE-39182 Kalmar, Sweden; (M.U.); (L.M.)
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8
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Horovitz A, Reingewertz TH, Cuéllar J, Valpuesta JM. Chaperonin Mechanisms: Multiple and (Mis)Understood? Annu Rev Biophys 2022; 51:115-133. [DOI: 10.1146/annurev-biophys-082521-113418] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The chaperonins are ubiquitous and essential nanomachines that assist in protein folding in an ATP-driven manner. They consist of two back-to-back stacked oligomeric rings with cavities in which protein (un)folding can take place in a shielding environment. This review focuses on GroEL from Escherichia coli and the eukaryotic chaperonin-containing t-complex polypeptide 1, which differ considerably in their reaction mechanisms despite sharing a similar overall architecture. Although chaperonins feature in many current biochemistry textbooks after being studied intensively for more than three decades, key aspects of their reaction mechanisms remain under debate and are discussed in this review. In particular, it is unclear whether a universal reaction mechanism operates for all substrates and whether it is passive, i.e., aggregation is prevented but the folding pathway is unaltered, or active. It is also unclear how chaperonin clients are distinguished from nonclients and what are the precise roles of the cofactors with which chaperonins interact. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Amnon Horovitz
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel; Amnon.H
| | - Tali Haviv Reingewertz
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel; Amnon.H
| | - Jorge Cuéllar
- Department of Macromolecular Structure, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - José María Valpuesta
- Department of Macromolecular Structure, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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9
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Barrick SK, Greenberg MJ. Cardiac myosin contraction and mechanotransduction in health and disease. J Biol Chem 2021; 297:101297. [PMID: 34634306 PMCID: PMC8559575 DOI: 10.1016/j.jbc.2021.101297] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/17/2022] Open
Abstract
Cardiac myosin is the molecular motor that powers heart contraction by converting chemical energy from ATP hydrolysis into mechanical force. The power output of the heart is tightly regulated to meet the physiological needs of the body. Recent multiscale studies spanning from molecules to tissues have revealed complex regulatory mechanisms that fine-tune cardiac contraction, in which myosin not only generates power output but also plays an active role in its regulation. Thus, myosin is both shaped by and actively involved in shaping its mechanical environment. Moreover, these studies have shown that cardiac myosin-generated tension affects physiological processes beyond muscle contraction. Here, we review these novel regulatory mechanisms, as well as the roles that myosin-based force generation and mechanotransduction play in development and disease. We describe how key intra- and intermolecular interactions contribute to the regulation of myosin-based contractility and the role of mechanical forces in tuning myosin function. We also discuss the emergence of cardiac myosin as a drug target for diseases including heart failure, leading to the discovery of therapeutics that directly tune myosin contractility. Finally, we highlight some of the outstanding questions that must be addressed to better understand myosin's functions and regulation, and we discuss prospects for translating these discoveries into precision medicine therapeutics targeting contractility and mechanotransduction.
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Affiliation(s)
- Samantha K Barrick
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael J Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA.
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10
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Donkervoort S, Kutzner CE, Hu Y, Lornage X, Rendu J, Stojkovic T, Baets J, Neuhaus SB, Tanboon J, Maroofian R, Bolduc V, Mroczek M, Conijn S, Kuntz NL, Töpf A, Monges S, Lubieniecki F, McCarty RM, Chao KR, Governali S, Böhm J, Boonyapisit K, Malfatti E, Sangruchi T, Horkayne-Szakaly I, Hedberg-Oldfors C, Efthymiou S, Noguchi S, Djeddi S, Iida A, di Rosa G, Fiorillo C, Salpietro V, Darin N, Fauré J, Houlden H, Oldfors A, Nishino I, de Ridder W, Straub V, Pokrzywa W, Laporte J, Foley AR, Romero NB, Ottenheijm C, Hoppe T, Bönnemann CG. Pathogenic Variants in the Myosin Chaperone UNC-45B Cause Progressive Myopathy with Eccentric Cores. Am J Hum Genet 2020; 107:1078-1095. [PMID: 33217308 DOI: 10.1016/j.ajhg.2020.11.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 11/03/2020] [Indexed: 01/03/2023] Open
Abstract
The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization.
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Affiliation(s)
- Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Carl E Kutzner
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xavière Lornage
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U1258, CNRS UMR7104, Université de Strasbourg, BP 10142, 67404 Illkirch, France
| | - John Rendu
- Centre Hospitalier Universitaire de Grenoble Alpes, Biochimie Génétique et Moléculaire, Grenoble 38000, France; Grenoble Institut des Neurosciences-INSERM U1216 UGA, Grenoble 38000, France
| | - Tanya Stojkovic
- Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Institut de Myologie, GHU La Pitié-Salpêtrière, Sorbonne Université, AP-HP, 75013 Paris, France
| | - Jonathan Baets
- Faculty of Medicine, University of Antwerp, 2610 Antwerp, Belgium; Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, 2610 Antwerp, Belgium; Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, 2650 Antwerp, Belgium
| | - Sarah B Neuhaus
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jantima Tanboon
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, 10700 Bangkok, Thailand; Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 187-8502 Tokyo, Japan
| | - Reza Maroofian
- Department of Neuromuscular Disorders, University College London Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Véronique Bolduc
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Magdalena Mroczek
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Stefan Conijn
- Department of Physiology, Amsterdam UMC (location VUmc), 1081 HZ Amsterdam, the Netherlands
| | - Nancy L Kuntz
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Soledad Monges
- Servicio de Neurología y Servicio de Patologia, Hospital de Pediatría Garrahan, C1245 AAM Buenos Aires, Argentina
| | - Fabiana Lubieniecki
- Servicio de Neurología y Servicio de Patologia, Hospital de Pediatría Garrahan, C1245 AAM Buenos Aires, Argentina
| | - Riley M McCarty
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Katherine R Chao
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Serena Governali
- Department of Physiology, Amsterdam UMC (location VUmc), 1081 HZ Amsterdam, the Netherlands
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U1258, CNRS UMR7104, Université de Strasbourg, BP 10142, 67404 Illkirch, France
| | - Kanokwan Boonyapisit
- Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol, University, 10700 Bangkok, Thailand
| | - Edoardo Malfatti
- Neurology Department, Raymond-Poincaré teaching hospital, centre de référence des maladies neuromusculaires Nord/Est/Ile-de-France, AP-HP, 92380 Garches, France
| | - Tumtip Sangruchi
- Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, 10700 Bangkok, Thailand
| | | | - Carola Hedberg-Oldfors
- Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, University College London Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Satoru Noguchi
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 187-8502 Tokyo, Japan; Department of Genome Medicine Development, Medical Genome Center, National Center of Neurology and Psychiatry, 187-8551 Tokyo, Japan
| | - Sarah Djeddi
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U1258, CNRS UMR7104, Université de Strasbourg, BP 10142, 67404 Illkirch, France
| | - Aritoshi Iida
- Department of Clinical Genome Analysis, Medical Genome Center, National Center of Neurology and Psychiatry, 187-8551 Tokyo, Japan
| | - Gabriella di Rosa
- Division of Child Neurology and Psychiatry, Department of the Adult and Developmental Age Human Pathology, University of Messina, Messina 98125, Italy
| | - Chiara Fiorillo
- Pediatric Neurology and Muscular Diseases Unit, G. Gaslini Institute, 16147 Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
| | - Vincenzo Salpietro
- Pediatric Neurology and Muscular Diseases Unit, G. Gaslini Institute, 16147 Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
| | - Niklas Darin
- Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, 41650 Gothenburg, Sweden
| | - Julien Fauré
- Centre Hospitalier Universitaire de Grenoble Alpes, Biochimie Génétique et Moléculaire, Grenoble 38000, France; Grenoble Institut des Neurosciences-INSERM U1216 UGA, Grenoble 38000, France
| | - Henry Houlden
- Department of Neuromuscular Disorders, University College London Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Anders Oldfors
- Department of Laboratory Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 187-8502 Tokyo, Japan; Department of Genome Medicine Development, Medical Genome Center, National Center of Neurology and Psychiatry, 187-8551 Tokyo, Japan; Department of Clinical Genome Analysis, Medical Genome Center, National Center of Neurology and Psychiatry, 187-8551 Tokyo, Japan
| | - Willem de Ridder
- Faculty of Medicine, University of Antwerp, 2610 Antwerp, Belgium; Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, 2610 Antwerp, Belgium; Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, 2650 Antwerp, Belgium
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK; Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE7 7DN, UK
| | - Wojciech Pokrzywa
- Laboratory of Protein Metabolism in Development and Aging, International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U1258, CNRS UMR7104, Université de Strasbourg, BP 10142, 67404 Illkirch, France
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Norma B Romero
- Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Institut de Myologie, GHU La Pitié-Salpêtrière, Sorbonne Université, AP-HP, 75013 Paris, France; Université Sorbonne, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, GH Pitié-Salpêtrière, 75651 Paris, France; Neuromuscular Morphology Unit, Myology Institute, GHU Pitié-Salpêtrière, 75013 Paris, France
| | - Coen Ottenheijm
- Department of Physiology, Amsterdam UMC (location VUmc), 1081 HZ Amsterdam, the Netherlands; Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85718, USA
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany.
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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Hypothesis: Single Actomyosin Properties Account for Ensemble Behavior in Active Muscle Shortening and Isometric Contraction. Int J Mol Sci 2020; 21:ijms21218399. [PMID: 33182367 PMCID: PMC7664901 DOI: 10.3390/ijms21218399] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 11/17/2022] Open
Abstract
Muscle contraction results from cyclic interactions between myosin II motors and actin with two sets of proteins organized in overlapping thick and thin filaments, respectively, in a nearly crystalline lattice in a muscle sarcomere. However, a sarcomere contains a huge number of other proteins, some with important roles in muscle contraction. In particular, these include thin filament proteins, troponin and tropomyosin; thick filament proteins, myosin binding protein C; and the elastic protein, titin, that connects the thin and thick filaments. Furthermore, the order and 3D organization of the myofilament lattice may be important per se for contractile function. It is possible to model muscle contraction based on actin and myosin alone with properties derived in studies using single molecules and biochemical solution kinetics. It is also possible to reproduce several features of muscle contraction in experiments using only isolated actin and myosin, arguing against the importance of order and accessory proteins. Therefore, in this paper, it is hypothesized that “single molecule actomyosin properties account for the contractile properties of a half sarcomere during shortening and isometric contraction at almost saturating Ca concentrations”. In this paper, existing evidence for and against this hypothesis is reviewed and new modeling results to support the arguments are presented. Finally, further experimental tests are proposed, which if they corroborate, at least approximately, the hypothesis, should significantly benefit future effective analysis of a range of experimental studies, as well as drug discovery efforts.
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12
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Under construction: The dynamic assembly, maintenance, and degradation of the cardiac sarcomere. J Mol Cell Cardiol 2020; 148:89-102. [PMID: 32920010 DOI: 10.1016/j.yjmcc.2020.08.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022]
Abstract
The sarcomere is the basic contractile unit of striated muscle and is a highly ordered protein complex with the actin and myosin filaments at its core. Assembling the sarcomere constituents into this organized structure in development, and with muscle growth as new sarcomeres are built, is a complex process coordinated by numerous factors. Once assembled, the sarcomere requires constant maintenance as its continuous contraction is accompanied by elevated mechanical, thermal, and oxidative stress, which predispose proteins to misfolding and toxic aggregation. To prevent protein misfolding and maintain sarcomere integrity, the sarcomere is monitored by an assortment of protein quality control (PQC) mechanisms. The need for effective PQC is heightened in cardiomyocytes which are terminally differentiated and must survive for many years while preserving optimal mechanical output. To prevent toxic protein aggregation, molecular chaperones stabilize denatured sarcomere proteins and promote their refolding. However, when old and misfolded proteins cannot be salvaged by chaperones, they must be recycled via degradation pathways: the calpain and ubiquitin-proteasome systems, which operate under basal conditions, and the stress-responsive autophagy-lysosome pathway. Mutations to and deficiency of the molecular chaperones and associated factors charged with sarcomere maintenance commonly lead to sarcomere structural disarray and the progression of heart disease, highlighting the necessity of effective sarcomere PQC for maintaining cardiac function. This review focuses on the dynamic regulation of assembly and turnover at the sarcomere with an emphasis on the chaperones involved in these processes and describes the alterations to chaperones - through mutations and deficient expression - implicated in disease progression to heart failure.
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13
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The TRiC/CCT Chaperonin and Its Role in Uncontrolled Proliferation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1243:21-40. [PMID: 32297209 DOI: 10.1007/978-3-030-40204-4_2] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The cell cycle is a sophisticated space-time regulated mechanism where a wide variety of protein modules and complexes associate functioning in a concerted manner to regulate and transfer the genetic material to daughter cells. CCT (chaperonin containing TCP-1, also known as TRiC) is a molecular machine that forms a high molecular weight complex (1000 KDa). CCT is emerging as a key molecule during mitosis due to its essential role in the folding of many important proteins involved in cell division (Cdh1, Plk1, p27, Cdc20, PP2a regulatory subunits, tubulin or actin) suggesting its involvement in uncontrolled proliferation. The assembly is formed by eight different subunits called CCTα, β, γ, δ, ε, ζ, η and θ in mammals corresponding to CCT1-8 in yeast. CCT/TRiC is organized in a unique intra- and inter-ring arrangement. The chaperonin monomers share a common domain structure including an equatorial domain, which contains all the inter-ring contacts, most of the intra-ring contacts and the ATP binding site, whose binding and hydrolysis triggers the conformational changes that take place during the functional cycle. All chaperonins display an open substrate-receptive conformation, where the unfolded protein is recognized and trapped, and a closed conformation where the substrate is isolated from the bulk of the intracellular environment. In this chapter we discuss the complex set of intra- and inter-ring allosteric signals during chaperonin function.
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14
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Hellerschmied D, Lehner A, Franicevic N, Arnese R, Johnson C, Vogel A, Meinhart A, Kurzbauer R, Deszcz L, Gazda L, Geeves M, Clausen T. Molecular features of the UNC-45 chaperone critical for binding and folding muscle myosin. Nat Commun 2019; 10:4781. [PMID: 31636255 PMCID: PMC6803673 DOI: 10.1038/s41467-019-12667-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 09/21/2019] [Indexed: 12/16/2022] Open
Abstract
Myosin is a motor protein that is essential for a variety of processes ranging from intracellular transport to muscle contraction. Folding and assembly of myosin relies on a specific chaperone, UNC-45. To address its substrate-targeting mechanism, we reconstitute the interplay between Caenorhabditis elegans UNC-45 and muscle myosin MHC-B in insect cells. In addition to providing a cellular chaperone assay, the established system enabled us to produce large amounts of functional muscle myosin, as evidenced by a biochemical and structural characterization, and to directly monitor substrate binding to UNC-45. Data from in vitro and cellular chaperone assays, together with crystal structures of binding-deficient UNC-45 mutants, highlight the importance of utilizing a flexible myosin-binding domain. This so-called UCS domain can adopt discrete conformations to efficiently bind and fold substrate. Moreover, our data uncover the molecular basis of temperature-sensitive UNC-45 mutations underlying one of the most prominent motility defects in C. elegans. Myosin, a motor protein essential for intracellular transport to muscle contraction, requires a chaperone UNC-45 for folding and assembly. Here authors use in vitro reconstitution and structural biology to characterize the interplay between UNC-45 and muscle myosin MHC-B.
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Affiliation(s)
- Doris Hellerschmied
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria. .,Faculty of Biology, Center of Medical Biotechnology, University Duisburg-Essen, Essen, Germany.
| | | | - Nina Franicevic
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Renato Arnese
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Chloe Johnson
- School of Biosciences, University of Kent, Canterbury, UK
| | - Antonia Vogel
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Anton Meinhart
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Robert Kurzbauer
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Luiza Deszcz
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Linn Gazda
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria
| | - Michael Geeves
- School of Biosciences, University of Kent, Canterbury, UK
| | - Tim Clausen
- Research Institute of Molecular Pathology, Vienna BioCenter, Vienna, Austria. .,Medical University Vienna, Vienna, Austria.
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15
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Walklate J, Ujfalusi Z, Behrens V, King EJ, Geeves MA. A micro-volume adaptation of a stopped-flow system; use with μg quantities of muscle proteins. Anal Biochem 2019; 581:113338. [PMID: 31201789 DOI: 10.1016/j.ab.2019.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 11/29/2022]
Abstract
Stopped-flow spectroscopy is a powerful method for measuring very fast biological and chemical reactions. The technique however is often limited by the volumes of reactants needed to load the system. Here we present a simple adaptation of commercial stopped-flow system that reduces the volume needed by a factor of 4 to ≈120 μl. After evaluation the volume requirements of the system we show that many standard myosin based assays can be performed using <100 μg of myosin. This adaptation both reduces the volume and therefore mass of protein required and also produces data of similar quality to that produced using the standard set up. The 100 μg of myosin required for these assays is less than that which can be isolated from 100 mg of muscle tissue. With this reduced quantity of myosin, assays using biopsy samples become possible. This will allow assays to be used to assist diagnoses, to examine the effects of post translational modifications on muscle proteins and to test potential therapeutic drugs using patient derived samples.
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Affiliation(s)
- J Walklate
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, United Kingdom
| | - Zoltan Ujfalusi
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, United Kingdom; Department of Biophysics, University of Pécs, Medical School, Szigeti Street 12, H-7624, Pécs, Hungary
| | - Vincent Behrens
- Molecular and Cell Physiology, Hannover Medical School, Germany
| | - Edward J King
- TgK Scientific Limited, 7 Long's Yard, St. Margaret's Street, Bradford on Avon, BA15 1DH, United Kingdom
| | - Michael A Geeves
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, United Kingdom.
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16
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Berger J, Berger S, Li M, Jacoby AS, Arner A, Bavi N, Stewart AG, Currie PD. In Vivo Function of the Chaperonin TRiC in α-Actin Folding during Sarcomere Assembly. Cell Rep 2019; 22:313-322. [PMID: 29320728 DOI: 10.1016/j.celrep.2017.12.069] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/11/2017] [Accepted: 12/19/2017] [Indexed: 12/14/2022] Open
Abstract
The TCP-1 ring complex (TRiC) is a multi-subunit group II chaperonin that assists nascent or misfolded proteins to attain their native conformation in an ATP-dependent manner. Functional studies in yeast have suggested that TRiC is an essential and generalized component of the protein-folding machinery of eukaryotic cells. However, TRiC's involvement in specific cellular processes within multicellular organisms is largely unknown because little validation of TRiC function exists in animals. Our in vivo analysis reveals a surprisingly specific role of TRiC in the biogenesis of skeletal muscle α-actin during sarcomere assembly in myofibers. TRiC acts at the sarcomere's Z-disk, where it is required for efficient assembly of actin thin filaments. Binding of ATP specifically by the TRiC subunit Cct5 is required for efficient actin folding in vivo. Furthermore, mutant α-actin isoforms that result in nemaline myopathy in patients obtain their pathogenic conformation via this function of TRiC.
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Affiliation(s)
- Joachim Berger
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; Victoria Node, EMBL Australia, Clayton, VIC 3800, Australia.
| | - Silke Berger
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; Victoria Node, EMBL Australia, Clayton, VIC 3800, Australia
| | - Mei Li
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; Victoria Node, EMBL Australia, Clayton, VIC 3800, Australia; Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Arie S Jacoby
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; Victoria Node, EMBL Australia, Clayton, VIC 3800, Australia
| | - Anders Arner
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Navid Bavi
- Department of Physiology, School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Alastair G Stewart
- Molecular, Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Peter D Currie
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia; Victoria Node, EMBL Australia, Clayton, VIC 3800, Australia.
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17
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Abstract
The eukaryotic group II chaperonin TRiC/CCT assists the folding of 10% of cytosolic proteins including many key structural and regulatory proteins. TRiC plays an essential role in maintaining protein homeostasis, and dysfunction of TRiC is closely related to human diseases including cancer and neurodegenerative diseases. TRiC consists of eight paralogous subunits, each of which plays a specific role in the assembly, allosteric cooperativity, and substrate recognition and folding of this complex macromolecular machine. TRiC-mediated substrate folding is regulated through its ATP-driven conformational changes. In recent years, progresses have been made on the structure, subunit arrangement, conformational cycle, and substrate folding of TRiC. Additionally, accumulating evidences also demonstrate the linkage between TRiC oligomer or monomer and diseases. In this review, we focus on the TRiC structure itself, TRiC assisted substrate folding, TRiC and disease, and the potential therapeutic application of TRiC in various diseases.
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Affiliation(s)
- Mingliang Jin
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Caixuan Liu
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Wenyu Han
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Yao Cong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
- Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China.
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18
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Ojima K, Ichimura E, Suzuki T, Oe M, Muroya S, Nishimura T. HSP90 modulates the myosin replacement rate in myofibrils. Am J Physiol Cell Physiol 2018; 315:C104-C114. [PMID: 29561661 DOI: 10.1152/ajpcell.00245.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myosin is a major myofibrillar component in skeletal muscles. In myofibrils, ~300 myosin molecules form a single thick filament in which there is constant turnover of myosin. Our previous study demonstrated that the myosin replacement rate is reduced by inhibition of protein synthesis (Ojima K, Ichimura E, Yasukawa Y, Wakamatsu J, Nishimura T, Am J Physiol Cell Physiol 309: C669-C679, 2015); however, additional factors influencing myosin replacement were unknown. Here, we showed that rapid myosin replacement requires heat shock protein 90 (HSP90) activity. We utilized the fluorescence recovery after photobleaching technique to measure the replacement rate of green fluorescent protein-fused myosin heavy chain (GFP-MYH) in myotubes overexpressing HSP90. Intriguingly, the myosin replacement rate was significantly increased in HSP90-overexpressing myotubes, whereas the myosin replacement rate slowed markedly in the presence of an HSP90-specific inhibitor, indicating that HSP90 activity promotes myosin replacement. To determine the mechanism of this effect, we investigated whether HSP90 activity increased the amount of myosin available for incorporation into myofibrils. Strikingly, the gene expression levels of MYHs were significantly elevated by HSP90 overexpression but downregulated by inhibition of HSP90 activity. Cytosolic myosin content was also increased in myotubes overexpressing HSP90. Taken together, our results demonstrate that HSP90 activity facilitates myosin replacement by upregulating MYH gene expression and thereby increasing cytosolic myosin content.
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Affiliation(s)
- Koichi Ojima
- Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba , Japan
| | - Emi Ichimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University , Sapporo , Japan
| | - Takahiro Suzuki
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University , Sapporo , Japan
| | - Mika Oe
- Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba , Japan
| | - Susumu Muroya
- Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba , Japan
| | - Takanori Nishimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University , Sapporo , Japan
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19
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Melkani GC, Bhide S, Han A, Vyas J, Livelo C, Bodmer R, Bernstein SI. TRiC/CCT chaperonins are essential for maintaining myofibril organization, cardiac physiological rhythm, and lifespan. FEBS Lett 2017; 591:3447-3458. [PMID: 28963798 PMCID: PMC5683924 DOI: 10.1002/1873-3468.12860] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/08/2017] [Accepted: 09/19/2017] [Indexed: 01/12/2023]
Abstract
We recently reported that CCT chaperonin subunits are upregulated in a cardiac-specific manner under time-restricted feeding (TRF) [Gill S et al. (2015) Science 347, 1265-1269], suggesting that TRiC/CCT has a heart-specific function. To understand the CCT chaperonin function in cardiomyocytes, we performed its cardiac-specific knock-down in the Drosophila melanogaster model. This resulted in disorganization of cardiac actin- and myosin-containing myofibrils and severe physiological dysfunction, including restricted heart diameters, elevated cardiac dysrhythmia and compromised cardiac performance. We also noted that cardiac-specific knock-down of CCT chaperonin significantly shortens lifespans. Additionally, disruption of circadian rhythm yields further deterioration of cardiac function of hypomorphic CCT mutants. Our analysis reveals that both the orchestration of protein folding and circadian rhythms mediated by CCT chaperonin are critical for maintaining heart contractility.
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Affiliation(s)
- Girish C. Melkani
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
| | - Shruti Bhide
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
| | - Andrew Han
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
| | - Jay Vyas
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
| | - Catherine Livelo
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
| | - Rolf Bodmer
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Sanford I. Bernstein
- Department of Biology, Molecular Biology and Heart Institutes, San Diego State University San Diego, CA 92182, USA
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20
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Melkani GC, Panda S. Time-restricted feeding for prevention and treatment of cardiometabolic disorders. J Physiol 2017; 595:3691-3700. [PMID: 28295377 PMCID: PMC5471414 DOI: 10.1113/jp273094] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 02/01/2017] [Indexed: 12/11/2022] Open
Abstract
The soaring prevalence of obesity and diabetes is associated with an increase in comorbidities, including elevated risk for cardiovascular diseases (CVDs). CVDs continue to be among the leading causes of death and disability in the United States. While increased nutritional intake from an energy-dense diet is known to disrupt metabolic homeostasis and contributes to the disease risk, circadian rhythm disruption is emerging as a new risk factor for CVD. Circadian rhythms coordinate cardiovascular health via temporal control of organismal metabolism and physiology. Thus, interventions that improve circadian rhythms are prospective entry points to mitigate cardiometabolic disease risk. Although light is a strong modulator of the neural circadian clock, time of food intake is emerging as a dominant agent that affects circadian clocks in metabolic organs. We discovered that imposing a time-restricted feeding (TRF) regimen in which all caloric intakes occur consistently within ≤ 12 h every day exerts many cardiometabolic benefits. TRF prevents excessive body weight gain, improves sleep, and attenuates age- and diet-induced deterioration in cardiac performance. Using an integrative approach that combines Drosophila melanogaster (fruit fly) genetics with transcriptome analyses it was found that the beneficial effects of TRF are mediated by circadian clock, ATP-dependent TCP/TRiC/CCT chaperonin and mitochondrial electron transport chain components. Parallel studies in rodents have shown TRF reduces metabolic disease risks by maintaining metabolic homeostasis. As modern humans continue to live under extended periods of wakefulness and ingestion events, daily eating pattern offers a new potential target for lifestyle intervention to reduce CVD risk.
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Affiliation(s)
- Girish C. Melkani
- Department of Biology, Molecular Biology and Heart InstitutesSan Diego State University San DiegoCA92182USA
| | - Satchidananda Panda
- Regulatory Biology LaboratorySalk Institute for Biological StudiesLa JollaCA92037USA
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21
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Greenberg MJ, Shuman H, Ostap EM. Measuring the Kinetic and Mechanical Properties of Non-processive Myosins Using Optical Tweezers. Methods Mol Biol 2017; 1486:483-509. [PMID: 27844441 DOI: 10.1007/978-1-4939-6421-5_19] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The myosin superfamily of molecular motors utilizes energy from ATP hydrolysis to generate force and motility along actin filaments in a diverse array of cellular processes. These motors are structurally, kinetically, and mechanically tuned to their specific molecular roles in the cell. Optical trapping techniques have played a central role in elucidating the mechanisms by which myosins generate force and in exposing the remarkable diversity of myosin functions. Here, we present thorough methods for measuring and analyzing interactions between actin and non-processive myosins using optical trapping techniques.
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Affiliation(s)
- Michael J Greenberg
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8231, St. Louis, MO, 63110, USA.
| | - Henry Shuman
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - E Michael Ostap
- Department of Physiology, The Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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22
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Walklate J, Ujfalusi Z, Geeves MA. Myosin isoforms and the mechanochemical cross-bridge cycle. ACTA ACUST UNITED AC 2016; 219:168-74. [PMID: 26792327 DOI: 10.1242/jeb.124594] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
At the latest count the myosin family includes 35 distinct groups, all of which have the conserved myosin motor domain attached to a neck or lever arm, followed by a highly variable tail or cargo binding region. The motor domain has an ATPase activity that is activated by the presence of actin. One feature of the myosin ATPase cycle is that it involves an association/dissociation with actin for each ATP hydrolysed. The cycle has been described in detail for a large number of myosins from different classes. In each case the cycle is similar, but the balance between the different molecular events in the cycle has been altered to produce a range of very different mechanical activities. Myosin may spend most of the ATPase cycle attached to actin (high duty ratio), as in the processive myosin (e.g. myosin V) or the strain-sensing myosins (e.g. myosin 1c). In contrast, most muscle myosins spend 80% of their ATPase cycle detached from actin. Within the myosin IIs found in human muscle, there are 11 different sarcomeric myosin isoforms, two smooth muscle isoforms as well as three non-muscle isoforms. We have been exploring how the different myosin isoforms have adapted the cross-bridge cycle to generate different types of mechanical activity and how this goes wrong in inherited myopathies. The ideas are outlined here.
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Affiliation(s)
| | - Zoltan Ujfalusi
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Michael A Geeves
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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23
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Minegishi Y, Sheng X, Yoshitake K, Sergeev Y, Iejima D, Shibagaki Y, Monma N, Ikeo K, Furuno M, Zhuang W, Liu Y, Rong W, Hattori S, Iwata T. CCT2 Mutations Evoke Leber Congenital Amaurosis due to Chaperone Complex Instability. Sci Rep 2016; 6:33742. [PMID: 27645772 PMCID: PMC5028737 DOI: 10.1038/srep33742] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 09/02/2016] [Indexed: 12/22/2022] Open
Abstract
Leber congenital amaurosis (LCA) is a hereditary early-onset retinal dystrophy that is accompanied by severe macular degeneration. In this study, novel compound heterozygous mutations were identified as LCA-causative in chaperonin-containing TCP-1, subunit 2 (CCT2), a gene that encodes the molecular chaperone protein, CCTβ. The zebrafish mutants of CCTβ are known to exhibit the eye phenotype while its mutation and association with human disease have been unknown. The CCT proteins (CCT α-θ) forms ring complex for its chaperon function. The LCA mutants of CCTβ, T400P and R516H, are biochemically instable and the affinity for the adjacent subunit, CCTγ, was affected distinctly in both mutants. The patient-derived induced pluripotent stem cells (iPSCs), carrying these CCTβ mutants, were less proliferative than the control iPSCs. Decreased proliferation under Cct2 knockdown in 661W cells was significantly rescued by wild-type CCTβ expression. However, the expression of T400P and R516H didn’t exhibit the significant effect. In mouse retina, both CCTβ and CCTγ are expressed in the retinal ganglion cells and connecting cilium of photoreceptor cells. The Cct2 knockdown decreased its major client protein, transducing β1 (Gβ1). Here we report the novel LCA mutations in CCTβ and the impact of chaperon disability by these mutations in cellular biology.
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Affiliation(s)
- Yuriko Minegishi
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - XunLun Sheng
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Kazutoshi Yoshitake
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daisuke Iejima
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Yoshio Shibagaki
- Division of Biochemistry, School of Pharmaceutical Science, Kitasato University, Tokyo, Japan
| | - Norikazu Monma
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Kazuho Ikeo
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Masaaki Furuno
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Life Science Accelerator Technology Group, Transcriptome Technology Team, Yokohama, Japan
| | - Wenjun Zhuang
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Yani Liu
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Weining Rong
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Seisuke Hattori
- Division of Biochemistry, School of Pharmaceutical Science, Kitasato University, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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24
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Bujalowski PJ, Nicholls P, Oberhauser AF. UNC-45B chaperone: the role of its domains in the interaction with the myosin motor domain. Biophys J 2015; 107:654-661. [PMID: 25099804 DOI: 10.1016/j.bpj.2014.05.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/22/2014] [Accepted: 05/29/2014] [Indexed: 11/15/2022] Open
Abstract
The proper folding of many proteins can only be achieved by interaction with molecular chaperones. The molecular chaperone UNC-45B is required for the folding of striated muscle myosin II. However, the precise mechanism by which it contributes to proper folding of the myosin head remains unclear. UNC-45B contains three domains: an N-terminal TPR domain known to bind Hsp90, a Central domain of unknown function, and a C-terminal UCS domain known to interact with the myosin head. Here we used fluorescence titrations methods, dynamic light scattering, and single-molecule atomic force microscopy (AFM) unfolding/refolding techniques to study the interactions of the UCS and Central domains with the myosin motor domain. We found that both the UCS and the Central domains bind to the myosin motor domain. Our data show that the domains bind to distinct subsites on the myosin head, suggesting distinct roles in forming the myosin-UNC-45B complex. To determine the chaperone activity of the UCS and Central domains, we used two different methods: 1), prevention of misfolding using single-molecule AFM, and 2), prevention of aggregation using dynamic light scattering. Using the first method, we found that the UCS domain is sufficient to prevent misfolding of a titin mechanical reporter. Application of the second method showed that the UCS domain but not the Central domain prevents the thermal aggregation of the myosin motor domain. We conclude that while both the UCS and the Central domains bind the myosin head with high affinity, only the UCS domain displays chaperone activity.
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Affiliation(s)
- Paul J Bujalowski
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas; Department of Biochemistry Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Paul Nicholls
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas; Department of Biochemistry Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Andres F Oberhauser
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas.
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25
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Up-Regulation of CCT8 Related to Neuronal Apoptosis after Traumatic Brain Injury in Adult Rats. Neurochem Res 2015; 40:1882-91. [DOI: 10.1007/s11064-015-1683-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 07/20/2015] [Accepted: 07/23/2015] [Indexed: 12/21/2022]
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26
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Aksel T, Choe Yu E, Sutton S, Ruppel KM, Spudich JA. Ensemble force changes that result from human cardiac myosin mutations and a small-molecule effector. Cell Rep 2015; 11:910-920. [PMID: 25937279 PMCID: PMC4431957 DOI: 10.1016/j.celrep.2015.04.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/19/2015] [Accepted: 04/01/2015] [Indexed: 11/24/2022] Open
Abstract
Cardiomyopathies due to mutations in human β-cardiac myosin are a significant cause of heart failure, sudden death, and arrhythmia. To understand the underlying molecular basis of changes in the contractile system's force production due to such mutations and search for potential drugs that restore force generation, an in vitro assay is necessary to evaluate cardiac myosin's ensemble force using purified proteins. Here, we characterize the ensemble force of human α- and β-cardiac myosin isoforms and those of β-cardiac myosins carrying left ventricular non-compaction (M531R) and dilated cardiomyopathy (S532P) mutations using a utrophin-based loaded in vitro motility assay and new filament-tracking software. Our results show that human α- and β-cardiac myosin, as well as the mutants, show opposite mechanical and enzymatic phenotypes with respect to each other. We also show that omecamtiv mecarbil, a previously discovered cardiac-specific myosin activator, increases β-cardiac myosin force generation.
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Affiliation(s)
- Tural Aksel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elizabeth Choe Yu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA; Cancer Biology Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shirley Sutton
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA.
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27
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Abstract
The UCS (UNC-45/CRO1/She4p) family of proteins has emerged as chaperones that are specific for the folding, assembly and function of myosin. These proteins participate in various important myosin-dependent cellular processes that include myofibril organization and muscle functions, cell differentiation, cardiac and skeletal muscle development, cytokinesis and endocytosis. Mutations in the genes that code for UCS proteins cause serious defects in these actomyosin-based processes. Homologs of UCS proteins can be broadly divided into (1) animal UCS proteins, generally known as UNC-45 proteins, which contain an N-terminal tetratricopeptide repeat (TPR) domain in addition to the canonical UCS domain, and (2) fungal UCS proteins, which lack the TPR domain. Structurally, except for TPR domain, both sub-classes of UCS proteins comprise of several irregular armadillo (ARM) repeats that are divided into two-domain architecture: a combined central-neck domain and a C-terminal UCS domain. Structural analyses suggest that UNC-45 proteins form elongated oligomers that serve as scaffolds to recruit Hsp90 and/or Hsp70 to form a multi-protein chaperoning complex that assists myosin heads to fold and simultaneously organize them into myofibrils. Similarly, fungal UCS proteins may dimerize to promote folding of non-muscle myosins as well as determine their step size along actin filaments. These findings confirm UCS proteins as a new class of myosin-specific chaperones and co-chaperones for Hsp90. This chapter reviews the implications of the outcome of studies on these proteins in cellular processes such as muscle formation, and disease states such as myopathies and cancer.
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Affiliation(s)
- Weiming Ni
- Department of Genetics, Howard Hughes Medical Institute, Yale School of Medicine, 06520, New Haven, CT, USA,
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28
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Bookwalter CS, Kelsen A, Leung JM, Ward GE, Trybus KM. A Toxoplasma gondii class XIV myosin, expressed in Sf9 cells with a parasite co-chaperone, requires two light chains for fast motility. J Biol Chem 2014; 289:30832-30841. [PMID: 25231988 DOI: 10.1074/jbc.m114.572453] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many diverse myosin classes can be expressed using the baculovirus/Sf9 insect cell expression system, whereas others have been recalcitrant. We hypothesized that most myosins utilize Sf9 cell chaperones, but others require an organism-specific co-chaperone. TgMyoA, a class XIVa myosin from the parasite Toxoplasma gondii, is required for the parasite to efficiently move and invade host cells. The T. gondii genome contains one UCS family myosin co-chaperone (TgUNC). TgMyoA expressed in Sf9 cells was soluble and functional only if the heavy and light chain(s) were co-expressed with TgUNC. The tetratricopeptide repeat domain of TgUNC was not essential to obtain functional myosin, implying that there are other mechanisms to recruit Hsp90. Purified TgMyoA heavy chain complexed with its regulatory light chain (TgMLC1) moved actin in a motility assay at a speed of ∼1.5 μm/s. When a putative essential light chain (TgELC1) was also bound, TgMyoA moved actin at more than twice that speed (∼3.4 μm/s). This result implies that two light chains bind to and stabilize the lever arm, the domain that amplifies small motions at the active site into the larger motions that propel actin at fast speeds. Our results show that the TgMyoA domain structure is more similar to other myosins than previously appreciated and provide a molecular explanation for how it moves actin at fast speeds. The ability to express milligram quantities of a class XIV myosin in a heterologous system paves the way for detailed structure-function analysis of TgMyoA and identification of small molecule inhibitors.
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Affiliation(s)
- Carol S Bookwalter
- Departments of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05405
| | - Anne Kelsen
- Departments of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Jacqueline M Leung
- Departments of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Gary E Ward
- Departments of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405.
| | - Kathleen M Trybus
- Departments of Molecular Physiology and Biophysics and University of Vermont, Burlington, Vermont 05405.
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29
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Smith DA, Carland CR, Guo Y, Bernstein SI. Getting folded: chaperone proteins in muscle development, maintenance and disease. Anat Rec (Hoboken) 2014; 297:1637-1649. [PMID: 25125177 PMCID: PMC4135391 DOI: 10.1002/ar.22980] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/11/2014] [Accepted: 04/12/2014] [Indexed: 09/26/2024]
Abstract
Chaperone proteins are critical for protein folding and stability, and hence are necessary for normal cellular organization and function. Recent studies have begun to interrogate the role of this specialized class of proteins in muscle biology. During development, chaperone-mediated folding of client proteins enables their integration into nascent functional sarcomeres. In addition to assisting with muscle differentiation, chaperones play a key role in the maintenance of muscle tissues. Furthermore, disruption of the chaperone network can result in neuromuscular disease. In this review, we discuss how chaperones are involved in myofibrillogenesis, sarcomere maintenance, and muscle disorders. We also consider the possibilities of therapeutically targeting chaperones to treat muscle disease.
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Affiliation(s)
- Daniel A. Smith
- Department of Biology and the Molecular Biology Institute, San Diego State
University, San Diego, CA 92182, USA
| | - Carmen R. Carland
- Department of Biology and the Molecular Biology Institute, San Diego State
University, San Diego, CA 92182, USA
| | - Yiming Guo
- Department of Biology and the Molecular Biology Institute, San Diego State
University, San Diego, CA 92182, USA
| | - Sanford I. Bernstein
- Department of Biology and the Molecular Biology Institute, San Diego State
University, San Diego, CA 92182, USA
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30
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Huang X, Wang X, Cheng C, Cai J, He S, Wang H, Liu F, Zhu C, Ding Z, Huang X, Zhang T, Zhang Y. Chaperonin containing TCP1, subunit 8 (CCT8) is upregulated in hepatocellular carcinoma and promotes HCC proliferation. APMIS 2014; 122:1070-9. [PMID: 24862099 DOI: 10.1111/apm.12258] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/02/2014] [Indexed: 12/25/2022]
Abstract
The development of molecular pathogenesis of hepatocellular carcinoma (HCC) is complex and involves alterations in the expression and conformation of assorted oncoproteins and tumor suppressors. Chaperonin containing TCP1 (CCT) is a cytolic molecular chaperone complex that is required for the correct folding of numerous proteins. In this study, we investigated a possible involvement of CCT subunit 8 (CCT8) in HCC development. Immunohistochemical analysis was performed in 102 human HCC samples. High CCT8 expression was detected in clinical HCC samples compared with adjacent noncancerous tissues. The univariate and multivariate survival analyses were also performed to determine their prognostic significance. Western blot confirmed the high expression of CCT8 in HCC compared with adjacent normal tissue. Moreover, the biological significance of the aberrant expression of CCT8 was investigated in HCC cell lines. Expression of CCT8 was correlated directly with the histologic grades and tumor size of HCC and high expression of CCT8 was associated with a poor prognosis. CCT8 depletion by siRNA inhibited cell proliferation and blocked S-phase entry in HuH7 cells. These results suggested that CCT8 might be an oncogene and participate in HCC cell proliferation. These findings provide a potential therapeutic strategy for the treatment of HCC.
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Affiliation(s)
- Xiaodong Huang
- Department of Pathology, Affiliated Cancer Hospital of Nantong University, Nantong University, Nantong
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31
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Kasembeli M, Lau WCY, Roh SH, Eckols TK, Frydman J, Chiu W, Tweardy DJ. Modulation of STAT3 folding and function by TRiC/CCT chaperonin. PLoS Biol 2014; 12:e1001844. [PMID: 24756126 PMCID: PMC3995649 DOI: 10.1371/journal.pbio.1001844] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 03/17/2014] [Indexed: 02/06/2023] Open
Abstract
Levels, folding, and function of the infamous cancer and inflammatory disease-related signaling molecule Stat3 are regulated by interaction with the chaperonin TRiC; manipulation of this interaction is a therapeutic avenue for exploration. Signal transducer and activator of transcription 3 (Stat3) transduces signals of many peptide hormones from the cell surface to the nucleus and functions as an oncoprotein in many types of cancers, yet little is known about how it achieves its native folded state within the cell. Here we show that Stat3 is a novel substrate of the ring-shaped hetero-oligomeric eukaryotic chaperonin, TRiC/CCT, which contributes to its biosynthesis and activity in vitro and in vivo. TRiC binding to Stat3 was mediated, at least in part, by TRiC subunit CCT3. Stat3 binding to TRiC mapped predominantly to the β-strand rich, DNA-binding domain of Stat3. Notably, enhancing Stat3 binding to TRiC by engineering an additional TRiC-binding domain from the von Hippel-Lindau protein (vTBD), at the N-terminus of Stat3, further increased its affinity for TRiC as well as its function, as determined by Stat3's ability to bind to its phosphotyrosyl-peptide ligand, an interaction critical for Stat3 activation. Thus, Stat3 levels and function are regulated by TRiC and can be modulated by manipulating its interaction with TRiC. Stat3 is a multidomain transcription factor that contributes to many cellular functions by transmitting signals for over 40 peptide hormones from the cell surface to the nucleus. Understanding how multidomain proteins achieve their fully folded and functional state is of substantial biological interest. As Stat3 signaling is up-regulated in many pathological conditions, including cancer and inflammatory diseases, insight into what controls its folding may be useful for the identification of vulnerabilities that can be therapeutically exploited. We demonstrate that the major protein-folding machine or chaperonin within eukaryotic cells, TRiC/CCT, is required for Stat3 to fold during its synthesis and for Stat3 to be fully functional within the cell. We also find that TRiC can refold chemically denatured Stat3 and provide evidence that the CCT3 subunit of TRiC binds to the DNA-binding domain of Stat3. We also show that Stat3 activity is decreased by down-modulating levels of TRiC and can be increased by increasing Stat3's interaction with TRiC. TRiC therefore regulates both Stat3 protein levels and its function, making Stat3 modulation by manipulation of its interaction with TRiC a potential approach for the treatment of cancer and inflammatory diseases.
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Affiliation(s)
- Moses Kasembeli
- Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wilson Chun Yu Lau
- Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Soung-Hun Roh
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - T. Kris Eckols
- Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - Judith Frydman
- Department of Biology and the BioX Program, Stanford University, Stanford, California, United States of America
| | - Wah Chiu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - David J. Tweardy
- Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Cellular and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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32
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Lee CF, Melkani GC, Bernstein SI. The UNC-45 myosin chaperone: from worms to flies to vertebrates. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 313:103-44. [PMID: 25376491 DOI: 10.1016/b978-0-12-800177-6.00004-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
UNC-45 (uncoordinated mutant number 45) is a UCS (UNC-45, CRO1, She4p) domain protein that is critical for myosin stability and function. It likely aides in folding myosin during cellular differentiation and maintenance, and protects myosin from denaturation during stress. Invertebrates have a single unc-45 gene that is expressed in both muscle and nonmuscle tissues. Vertebrates possess one gene expressed in striated muscle (unc-45b) and another that is more generally expressed (unc-45a). Structurally, UNC-45 is composed of a series of α-helices connected by loops. It has an N-terminal tetratricopeptide repeat domain that binds to Hsp90 and a central domain composed of armadillo repeats. Its C-terminal UCS domain, which is also comprised of helical armadillo repeats, interacts with myosin. In this chapter, we present biochemical, structural, and genetic analyses of UNC-45 in Caenorhabditis elegans, Drosophila melanogaster, and various vertebrates. Further, we provide insights into UNC-45 functions, its potential mechanism of action, and its roles in human disease.
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Affiliation(s)
- Chi F Lee
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Girish C Melkani
- Department of Biology, San Diego State University, San Diego, CA, USA
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33
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Hellerschmied D, Clausen T. Myosin chaperones. Curr Opin Struct Biol 2013; 25:9-15. [PMID: 24440450 PMCID: PMC4045384 DOI: 10.1016/j.sbi.2013.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/08/2013] [Accepted: 11/08/2013] [Indexed: 12/31/2022]
Abstract
The folding and assembly of myosin motor proteins is essential for most movement processes at the cellular, but also at the organism level. Importantly, myosins, which represent a very diverse family of proteins, require the activity of general and specialized folding factors to develop their full motor function. The activities of the myosin-specific UCS (UNC-45/Cro1/She4) chaperones range from assisting acto-myosin dependent transport processes to scaffolding multi-subunit chaperone complexes, which are required to assemble myofilaments. Recent structure-function studies revealed the structural organization of TPR (tetratricopeptide repeat)-containing and TPR-less UCS chaperones. The observed structural differences seem to reflect the specialized and remarkably versatile working mechanisms of myosin-directed chaperones, as will be discussed in this review.
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Affiliation(s)
- Doris Hellerschmied
- Research Institute of Molecular Pathology, Dr. Bohrgasse 7, A-1030 Vienna, Austria
| | - Tim Clausen
- Research Institute of Molecular Pathology, Dr. Bohrgasse 7, A-1030 Vienna, Austria.
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34
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Preller M, Manstein D. Myosin Structure, Allostery, and Mechano-Chemistry. Structure 2013; 21:1911-22. [DOI: 10.1016/j.str.2013.09.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/19/2013] [Accepted: 09/25/2013] [Indexed: 01/10/2023]
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35
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Li H, Zhong Y, Wang Z, Gao J, Xu J, Chu W, Zhang J, Fang S, Du SJ. Smyd1b is required for skeletal and cardiac muscle function in zebrafish. Mol Biol Cell 2013; 24:3511-21. [PMID: 24068325 PMCID: PMC3826989 DOI: 10.1091/mbc.e13-06-0352] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Myofibrillogenesis is critical for muscle cell differentiation and contraction. This study shows that Smyd1b plays a key role in myofibrillogenesis in muscle cells. Knockdown of smyd1b results in up-regulation of hsp90α1 and unc45b gene expression, increased myosin degradation, and disruption of sarcomere organization in zebrafish embryos. Smyd1b is a member of the Smyd family that is specifically expressed in skeletal and cardiac muscles. Smyd1b plays a key role in thick filament assembly during myofibrillogenesis in skeletal muscles of zebrafish embryos. To better characterize Smyd1b function and its mechanism of action in myofibrillogenesis, we analyzed the effects of smyd1b knockdown on myofibrillogenesis in skeletal and cardiac muscles of zebrafish embryos. The results show that knockdown of smyd1b causes significant disruption of myofibril organization in both skeletal and cardiac muscles of zebrafish embryos. Microarray and quantitative reverse transcription-PCR analyses show that knockdown of smyd1b up-regulates heat shock protein 90 (hsp90) and unc45b gene expression. Biochemical analysis reveals that Smyd1b can be coimmunoprecipitated with heat shock protein 90 α-1 and Unc45b, two myosin chaperones expressed in muscle cells. Consistent with its potential function in myosin folding and assembly, knockdown of smyd1b significantly reduces myosin protein accumulation without affecting mRNA expression. This likely results from increased myosin degradation involving unc45b overexpression. Together these data support the idea that Smyd1b may work together with myosin chaperones to control myosin folding, degradation, and assembly into sarcomeres during myofibrillogenesis.
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Affiliation(s)
- Huiqing Li
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21202 Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201 Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20892 Department of Bioengineering and Environmental Science, Changsha University, Hunan 410003, China
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Lowey S, Bretton V, Gulick J, Robbins J, Trybus KM. Transgenic mouse α- and β-cardiac myosins containing the R403Q mutation show isoform-dependent transient kinetic differences. J Biol Chem 2013; 288:14780-7. [PMID: 23580644 DOI: 10.1074/jbc.m113.450668] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) is a major cause of sudden cardiac death in young athletes. The discovery in 1990 that a point mutation at residue 403 (R403Q) in the β-myosin heavy chain (MHC) caused a severe form of FHC was the first of many demonstrations linking FHC to mutations in muscle proteins. A mouse model for FHC has been widely used to study the mechanochemical properties of mutated cardiac myosin, but mouse hearts express α-MHC, whereas the ventricles of larger mammals express predominantly β-MHC. To address the role of the isoform backbone on function, we generated a transgenic mouse in which the endogenous α-MHC was partially replaced with transgenically encoded β-MHC or α-MHC. A His6 tag was cloned at the N terminus, along with R403Q, to facilitate isolation of myosin subfragment 1 (S1). Stopped flow kinetics were used to measure the equilibrium constants and rates of nucleotide binding and release for the mouse S1 isoforms bound to actin. For the wild-type isoforms, we found that the affinity of MgADP for α-S1 (100 μM) is ~ 4-fold weaker than for β-S1 (25 μM). Correspondingly, the MgADP release rate for α-S1 (350 s(-1)) is ~3-fold greater than for β-S1 (120 s(-1)). Introducing the R403Q mutation caused only a minor reduction in kinetics for β-S1, but R403Q in α-S1 caused the ADP release rate to increase by 20% (430 s(-1)). These transient kinetic studies on mouse cardiac myosins provide strong evidence that the functional impact of an FHC mutation on myosin depends on the isoform backbone.
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Affiliation(s)
- Susan Lowey
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA.
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37
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Bujalowski PJ, Oberhauser AF. Tracking unfolding and refolding reactions of single proteins using atomic force microscopy methods. Methods 2013; 60:151-60. [PMID: 23523554 DOI: 10.1016/j.ymeth.2013.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 11/26/2022] Open
Abstract
During the last two decades single-molecule manipulation techniques such as atomic force microscopy (AFM) has risen to prominence through their unique capacity to provide fundamental information on the structure and function of biomolecules. Here we describe the use of single-molecule AFM to track protein unfolding and refolding pathways, enzymatic catalysis and the effects of osmolytes and chaperones on protein stability and folding. We will outline the principles of operation for two different AFM pulling techniques: length clamp and force-clamp and discuss prominent applications. We provide protocols for the construction of polyproteins which are amenable for AFM experiments, the preparation of different coverslips, choice and calibration of AFM cantilevers. We also discuss the selection criteria for AFM recordings, the calibration of AFM cantilevers, protein sample preparations and analysis of the obtained data.
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Affiliation(s)
- Paul J Bujalowski
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, TX 77555, USA
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Kaiser CM, Bujalowski PJ, Ma L, Anderson J, Epstein HF, Oberhauser AF. Tracking UNC-45 chaperone-myosin interaction with a titin mechanical reporter. Biophys J 2012; 102:2212-9. [PMID: 22824286 DOI: 10.1016/j.bpj.2012.03.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 03/01/2012] [Accepted: 03/06/2012] [Indexed: 01/26/2023] Open
Abstract
Myosins are molecular motors that convert chemical energy into mechanical work. Allosterically coupling ATP-binding, hydrolysis, and binding/dissociation to actin filaments requires precise and coordinated structural changes that are achieved by the structurally complex myosin motor domain. UNC-45, a member of the UNC-45/Cro1/She4p family of proteins, acts as a chaperone for myosin and is essential for proper folding and assembly of myosin into muscle thick filaments in vivo. The molecular mechanisms by which UNC-45 interacts with myosin to promote proper folding of the myosin head domain are not known. We have devised a novel approach, to our knowledge, to analyze the interaction of UNC-45 with the myosin motor domain at the single molecule level using atomic force microscopy. By chemically coupling a titin I27 polyprotein to the motor domain of myosin, we introduced a mechanical reporter. In addition, the polyprotein provided a specific attachment point and an unambiguous mechanical fingerprint, facilitating our atomic force microscopy measurements. This approach enabled us to study UNC-45-motor domain interactions. After mechanical unfolding, the motor domain interfered with refolding of the otherwise robust I27 modules, presumably by recruiting them into a misfolded state. In the presence of UNC-45, I27 folding was restored. Our single molecule approach enables the study of UNC-45 chaperone interactions with myosin and their consequences for motor domain folding and misfolding in mechanistic detail.
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Affiliation(s)
- Christian M Kaiser
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
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39
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Deacon JC, Bloemink MJ, Rezavandi H, Geeves MA, Leinwand LA. Erratum to: Identification of functional differences between recombinant human α and β cardiac myosin motors. Cell Mol Life Sci 2012; 69:4239-55. [PMID: 23001010 PMCID: PMC3685716 DOI: 10.1007/s00018-012-1111-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The myosin isoform composition of the heart is dynamic in health and disease and has been shown to affect contractile velocity and force generation. While different mammalian species express different proportions of α and β myosin heavy chain, healthy human heart ventricles express these isoforms in a ratio of about 1:9 (α:β) while failing human ventricles express no detectable α-myosin. We report here fast-kinetic analysis of recombinant human α and β myosin heavy chain motor domains. This represents the first such analysis of any human muscle myosin motor and the first of α-myosin from any species. Our findings reveal substantial isoform differences in individual kinetic parameters, overall contractile character, and predicted cycle times. For these parameters, α-subfragment 1 (S1) is far more similar to adult fast skeletal muscle myosin isoforms than to the slow β isoform despite 91% sequence identity between the motor domains of α- and β-myosin. Among the features that differentiate α- from β-S1: the ATP hydrolysis step of α-S1 is ~ten-fold faster than β-S1, α-S1 exhibits ~five-fold weaker actin affinity than β-S1, and actin·α-S1 exhibits rapid ADP release, which is >ten-fold faster than ADP release for β-S1. Overall, the cycle times are ten-fold faster for α-S1 but the portion of time each myosin spends tightly bound to actin (the duty ratio) is similar. Sequence analysis points to regions that might underlie the basis for this finding.
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Affiliation(s)
- John C. Deacon
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
| | | | - Heresh Rezavandi
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | | | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
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40
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Deacon JC, Bloemink MJ, Rezavandi H, Geeves MA, Leinwand LA. Identification of functional differences between recombinant human α and β cardiac myosin motors. Cell Mol Life Sci 2012; 69:2261-77. [PMID: 22349210 PMCID: PMC3375423 DOI: 10.1007/s00018-012-0927-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 12/29/2011] [Accepted: 01/19/2012] [Indexed: 11/24/2022]
Abstract
The myosin isoform composition of the heart is dynamic in health and disease and has been shown to affect contractile velocity and force generation. While different mammalian species express different proportions of α and β myosin heavy chain, healthy human heart ventricles express these isoforms in a ratio of about 1:9 (α:β) while failing human ventricles express no detectable α-myosin. We report here fast-kinetic analysis of recombinant human α and β myosin heavy chain motor domains. This represents the first such analysis of any human muscle myosin motor and the first of α-myosin from any species. Our findings reveal substantial isoform differences in individual kinetic parameters, overall contractile character, and predicted cycle times. For these parameters, α-subfragment 1 (S1) is far more similar to adult fast skeletal muscle myosin isoforms than to the slow β isoform despite 91% sequence identity between the motor domains of α- and β-myosin. Among the features that differentiate α- from β-S1: the ATP hydrolysis step of α-S1 is ~ten-fold faster than β-S1, α-S1 exhibits ~five-fold weaker actin affinity than β-S1, and actin·α-S1 exhibits rapid ADP release, which is >ten-fold faster than ADP release for β-S1. Overall, the cycle times are ten-fold faster for α-S1 but the portion of time each myosin spends tightly bound to actin (the duty ratio) is similar. Sequence analysis points to regions that might underlie the basis for this finding.
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Affiliation(s)
- John C. Deacon
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
| | | | - Heresh Rezavandi
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | | | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
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41
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At the Start of the Sarcomere: A Previously Unrecognized Role for Myosin Chaperones and Associated Proteins during Early Myofibrillogenesis. Biochem Res Int 2012; 2012:712315. [PMID: 22400118 PMCID: PMC3287041 DOI: 10.1155/2012/712315] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 10/10/2011] [Indexed: 01/03/2023] Open
Abstract
The development of striated muscle in vertebrates requires the assembly of contractile myofibrils, consisting of highly ordered bundles of protein filaments. Myofibril formation occurs by the stepwise addition of complex proteins, a process that is mediated by a variety of molecular chaperones and quality control factors. Most notably, myosin of the thick filament requires specialized chaperone activity during late myofibrillogenesis, including that of Hsp90 and its cofactor, Unc45b. Unc45b has been proposed to act exclusively as an adaptor molecule, stabilizing interactions between Hsp90 and myosin; however, recent discoveries in zebrafish and C. elegans suggest the possibility of an earlier role for Unc45b during myofibrillogenesis. This role may involve functional control of nonmuscle myosins during the earliest stages of myogenesis, when premyofibril scaffolds are first formed from dynamic cytoskeletal actin. This paper will outline several lines of evidence that converge to build a model for Unc45b activity during early myofibrillogenesis.
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42
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Buvoli M, Buvoli A, Leinwand LA. Effects of pathogenic proline mutations on myosin assembly. J Mol Biol 2011; 415:807-18. [PMID: 22155079 DOI: 10.1016/j.jmb.2011.11.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/04/2011] [Accepted: 11/23/2011] [Indexed: 12/27/2022]
Abstract
Laing distal myopathy (MPD1) is a genetically dominant myopathy characterized by early and selective weakness of the distal muscles. Mutations in the MYH7 gene encoding for the β-myosin heavy chain are the underlying genetic cause of MPD1. However, their pathogenic mechanisms are currently unknown. Here, we measure the biological effects of the R1500P and L1706P MPD1 mutations in different cellular systems. We show that, while the two mutations inhibit myosin self-assembly in non-muscle cells, they do not prevent incorporation of the mutant myosin into sarcomeres. Nevertheless, we find that the L1706P mutation affects proper antiparallel myosin association by accumulating in the bare zone of the sarcomere. Furthermore, bimolecular fluorescence complementation assay shows that the α-helix containing the R1500P mutation folds into homodimeric (mutant/mutant) and heterodimeric [mutant/wild type (WT)] myosin molecules that are competent for sarcomere incorporation. Both mutations also form aggregates consisting of cytoplasmic vacuoles surrounding paracrystalline arrays and amorphous rod-like inclusions that sequester WT myosin. Myosin aggregates were also detected in transgenic nematodes expressing the R1500P mutation. By showing that the two MPD1 mutations can have dominant effects on distinct components of the contractile apparatus, our data provide the first insights into the pathogenesis of the disease.
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Affiliation(s)
- Massimo Buvoli
- Department of Molecular, Cellular, and Developmental Biology and Biofrontiers Institute, University of Colorado, Boulder, CO 80309, USA
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43
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Just S, Meder B, Berger IM, Etard C, Trano N, Patzel E, Hassel D, Marquart S, Dahme T, Vogel B, Fishman MC, Katus HA, Strähle U, Rottbauer W. The myosin-interacting protein SMYD1 is essential for sarcomere organization. J Cell Sci 2011; 124:3127-36. [PMID: 21852424 DOI: 10.1242/jcs.084772] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
Assembly, maintenance and renewal of sarcomeres require highly organized and balanced folding, transport, modification and degradation of sarcomeric proteins. However, the molecules that mediate these processes are largely unknown. Here, we isolated the zebrafish mutant flatline (fla), which shows disturbed sarcomere assembly exclusively in heart and fast-twitch skeletal muscle. By positional cloning we identified a nonsense mutation within the SET- and MYND-domain-containing protein 1 gene (smyd1) to be responsible for the fla phenotype. We found SMYD1 expression to be restricted to the heart and fast-twitch skeletal muscle cells. Within these cell types, SMYD1 localizes to both the sarcomeric M-line, where it physically associates with myosin, and the nucleus, where it supposedly represses transcription through its SET and MYND domains. However, although we found transcript levels of thick filament chaperones, such as Hsp90a1 and UNC-45b, to be severely upregulated in fla, its histone methyltransferase activity - mainly responsible for the nuclear function of SMYD1 - is dispensable for sarcomerogenesis. Accordingly, sarcomere assembly in fla mutant embryos can be reconstituted by ectopically expressing histone methyltransferase-deficient SMYD1. By contrast, ectopic expression of myosin-binding-deficient SMYD1 does not rescue fla mutants, implicating an essential role for the SMYD1-myosin interaction in cardiac and fast-twitch skeletal muscle thick filament assembly.
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Affiliation(s)
- Steffen Just
- Department of Medicine II, University of Ulm, 89081 Ulm, Germany
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Melkani GC, Bodmer R, Ocorr K, Bernstein SI. The UNC-45 chaperone is critical for establishing myosin-based myofibrillar organization and cardiac contractility in the Drosophila heart model. PLoS One 2011; 6:e22579. [PMID: 21799905 PMCID: PMC3143160 DOI: 10.1371/journal.pone.0022579] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 06/24/2011] [Indexed: 11/25/2022] Open
Abstract
UNC-45 is a UCS (UNC-45/CRO1/She4P) class chaperone necessary for myosin folding and/or accumulation, but its requirement for maintaining cardiac contractility has not been explored. Given the prevalence of myosin mutations in eliciting cardiomyopathy, chaperones like UNC-45 are likely to be equally critical in provoking or modulating myosin-associated cardiomyopathy. Here, we used the Drosophila heart model to examine its role in cardiac physiology, in conjunction with RNAi-mediated gene silencing specifically in the heart in vivo. Analysis of cardiac physiology was carried out using high-speed video recording in conjunction with movement analysis algorithms. unc-45 knockdown resulted in severely compromised cardiac function in adults as evidenced by prolonged diastolic and systolic intervals, and increased incidence of arrhythmias and extreme dilation; the latter was accompanied by a significant reduction in muscle contractility. Structural analysis showed reduced myofibrils, myofibrillar disarray, and greatly decreased cardiac myosin accumulation. Cardiac unc-45 silencing also dramatically reduced life-span. In contrast, third instar larval and young pupal hearts showed mild cardiac abnormalities, as severe cardiac defects only developed during metamorphosis. Furthermore, cardiac unc-45 silencing in the adult heart (after metamorphosis) led to less severe phenotypes. This suggests that UNC-45 is mostly required for myosin accumulation/folding during remodeling of the forming adult heart. The cardiac defects, myosin deficit and decreased life-span in flies upon heart-specific unc-45 knockdown were significantly rescued by UNC-45 over-expression. Our results are the first to demonstrate a cardiac-specific requirement of a chaperone in Drosophila, suggestive of a critical role of UNC-45 in cardiomyopathies, including those associated with unfolded proteins in the failing human heart. The dilated cardiomyopathy phenotype associated with UNC-45 deficiency is mimicked by myosin knockdown suggesting that UNC-45 plays a crucial role in stabilizing myosin and possibly preventing human cardiomyopathies associated with functional deficiencies of myosin.
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Affiliation(s)
- Girish C. Melkani
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, California, United States of America
- Development and Aging Program, Sanford-Burnham Institute for Medical Research, La Jolla, California, United States of America
| | - Rolf Bodmer
- Development and Aging Program, Sanford-Burnham Institute for Medical Research, La Jolla, California, United States of America
| | - Karen Ocorr
- Development and Aging Program, Sanford-Burnham Institute for Medical Research, La Jolla, California, United States of America
- * E-mail: (SIB); (KO)
| | - Sanford I. Bernstein
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, California, United States of America
- * E-mail: (SIB); (KO)
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45
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Differential turnover of myosin chaperone UNC-45A isoforms increases in metastatic human breast cancer. J Mol Biol 2011; 412:365-78. [PMID: 21802425 DOI: 10.1016/j.jmb.2011.07.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/08/2011] [Accepted: 07/12/2011] [Indexed: 01/10/2023]
Abstract
UNC-45A is a molecular chaperone targeted to non-muscle myosins and is essential for cell division. Here, we show that UNC-45A mRNA and protein expression was elevated in human breast carcinomas and cell lines derived from breast carcinoma metastases. Moreover, small hairpin RNA knockdowns of endogenously overexpressed UNC-45A in the most metastatic cell line led to significant decreases in the rates of cell proliferation and invasion, concomitant with reduction in the interaction of myosin II with actin filaments. Exploring the mechanism of these findings further, we found that UNC-45A is alternatively expressed at the mRNA and protein levels as two isoforms. The two isoforms differ only by a proline-rich 15-amino-acid sequence near the amino-terminus. In the increased expression with metastatic activity, the ratio of the isoform mRNAs remained constant, but the 929-amino-acid protein isoform showed increases up to about 3-fold in comparison to the 944-amino-acid isoform. The differential accumulation was explained by cellular labeling experiments that showed that the 944 isoform is degraded at a 5-fold greater rate than the 929 isoform and that this degradation required the ubiquitin-proteasome system.
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46
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Scaffolds and chaperones in myofibril assembly: putting the striations in striated muscle. Biophys Rev 2011; 3:25-32. [PMID: 21666840 DOI: 10.1007/s12551-011-0043-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sarcomere assembly in striated muscles has long been described as a series of steps leading to assembly of individual proteins into thick filaments, thin filaments and Z-lines. Decades of previous work focused on the order in which various structural proteins adopted the striated organization typical of mature myofibrils. These studies led to the view that actin and α-actinin assemble into premyofibril structures separately from myosin filaments, and that these structures are then assembled into myofibrils with centered myosin filaments and actin filaments anchored at the Z-lines. More recent studies have shown that particular scaffolding proteins and chaperone proteins are required for individual steps in assembly. Here, we review the evidence that N-RAP, a LIM domain and nebulin repeat protein, scaffolds assembly of actin and α-actinin into I-Z-I structures in the first steps of assembly; that the heat shock chaperone proteins Hsp90 & Hsc70 cooperate with UNC-45 to direct the folding of muscle myosin and its assembly into thick filaments; and that the kelch repeat protein Krp1 promotes lateral fusion of premyofibril structures to form mature striated myofibrils. The evidence shows that myofibril assembly is a complex process that requires the action of particular catalysts and scaffolds at individual steps. The scaffolds and chaperones required for assembly are potential regulators of myofibrillogenesis, and abnormal function of these proteins caused by mutation or pathological processes could in principle contribute to diseases of cardiac and skeletal muscles.
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Lee CF, Melkani GC, Yu Q, Suggs JA, Kronert WA, Suzuki Y, Hipolito L, Price MG, Epstein HF, Bernstein SI. Drosophila UNC-45 accumulates in embryonic blastoderm and in muscles, and is essential for muscle myosin stability. J Cell Sci 2011; 124:699-705. [PMID: 21285246 DOI: 10.1242/jcs.078964] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
UNC-45 is a chaperone that facilitates folding of myosin motor domains. We have used Drosophila melanogaster to investigate the role of UNC-45 in muscle development and function. Drosophila UNC-45 (dUNC-45) is expressed at all developmental stages. It colocalizes with non-muscle myosin in embryonic blastoderm of 2-hour-old embryos. At 14 hours, it accumulates most strongly in embryonic striated muscles, similarly to muscle myosin. dUNC-45 localizes to the Z-discs of sarcomeres in third instar larval body-wall muscles. We produced a dunc-45 mutant in which zygotic expression is disrupted. This results in nearly undetectable dUNC-45 levels in maturing embryos as well as late embryonic lethality. Muscle myosin accumulation is robust in dunc-45 mutant embryos at 14 hours. However, myosin is dramatically decreased in the body-wall muscles of 22-hour-old mutant embryos. Furthermore, electron microscopy showed only a few thick filaments and irregular thick-thin filament lattice spacing. The lethality, defective protein accumulation, and ultrastructural abnormalities are rescued with a wild-type dunc-45 transgene, indicating that the mutant phenotypes arise from the dUNC-45 deficiency. Overall, our data indicate that dUNC-45 is important for myosin accumulation and muscle function. Furthermore, our results suggest that dUNC-45 acts post-translationally for proper myosin folding and maturation.
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Affiliation(s)
- Chi F Lee
- Department of Biology and the Molecular Biology Institute, San Diego State University, San Diego, CA 92182, USA
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48
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A proteomic analysis of PKCε targets in astrocytes: implications for astrogliosis. Amino Acids 2010; 40:641-51. [PMID: 20640460 DOI: 10.1007/s00726-010-0691-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 07/06/2010] [Indexed: 12/16/2022]
Abstract
Astrocytes are glial cells in the central nervous system (CNS) that play key roles in brain physiology, controlling processes, such as neurogenesis, brain energy metabolism and synaptic transmission. Recently, immune functions have also been demonstrated in astrocytes, influencing neuronal survival in the course of neuroinflammatory pathologies. In this regard, PKCepsilon (PKCε) is a protein kinase with an outstanding role in inflammation. Our previous findings indicating that PKCε regulates voltage-dependent calcium channels as well as morphological stellation imply that this kinase controls multiple signalling pathways within astrocytes, including those implicated in activation of immune functions. The present study applies proteomics to investigate new protein targets of PKCε in astrocytes. Primary astrocyte cultures infected with an adenovirus that expresses constitutively active PKCε were compared with infection controls. Two-dimensional gel electrophoresis clearly detected 549 spots in cultured astrocytes, and analysis of differential protein expression revealed 18 spots regulated by PKCε. Protein identification by mass spectrometry (nano-LC-ESI-MS/MS) showed that PKCε targets molecules with heterogeneous functions, including chaperones, cytoskeletal components and proteins implicated in metabolism and signalling. These results support the notion that PKCε is involved in astrocyte activation; also suggesting that multiple astrocyte-dependent processes are regulated by PKCε, including those associated to neuroinflammation.
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49
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Moncman CL, Andrade FH. Nonmuscle myosin IIB, a sarcomeric component in the extraocular muscles. Exp Cell Res 2010; 316:1958-65. [PMID: 20350540 DOI: 10.1016/j.yexcr.2010.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 03/19/2010] [Accepted: 03/22/2010] [Indexed: 12/26/2022]
Abstract
Extraocular muscles (EOMs) are categorized as skeletal muscles; however, emerging evidence indicates that their gene expression profile, metabolic characteristics and functional properties are significantly different from the prototypical members of this muscle class. Gene expression profiling of developing and adult EOM suggest that many myofilament and cytoskeletal proteins have unique expression patterns in EOMs, including the maintained expression of embryonic and fetal isoforms of myosin heavy chains (MyHC), the presence of a unique EOM specific MyHC and mixtures of both cardiac and skeletal muscle isoforms of thick and thin filament accessory proteins. We demonstrate that nonmuscle myosin IIB (nmMyH IIB) is a sarcomeric component in approximately 20% of the global layer fibers in adult rat EOMs. Comparisons of the myofibrillar distribution of nmMyHC IIB with sarcomeric MyHCs indicate that nmMyH IIB co-exists with slow MyHC isoforms. In longitudinal sections of adult rat EOM, nmMyHC IIB appears to be restricted to the A-bands. Although nmMyHC IIB has been previously identified as a component of skeletal and cardiac sarcomeres at the level of the Z-line, the novel distribution of this protein within the A band in EOMs is further evidence of both the EOMs complexity and unconventional phenotype.
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Affiliation(s)
- Carole L Moncman
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA.
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de Groot NS, Ventura S. Protein aggregation profile of the bacterial cytosol. PLoS One 2010; 5:e9383. [PMID: 20195530 PMCID: PMC2828471 DOI: 10.1371/journal.pone.0009383] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Accepted: 01/30/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Protein misfolding is usually deleterious for the cell, either as a consequence of the loss of protein function or the buildup of insoluble and toxic aggregates. The aggregation behavior of a given polypeptide is strongly influenced by the intrinsic properties encoded in its sequence. This has allowed the development of effective computational methods to predict protein aggregation propensity. METHODOLOGY/PRINCIPAL FINDINGS Here, we use the AGGRESCAN algorithm to approximate the aggregation profile of an experimental cytosolic Escherichia coli proteome. The analysis indicates that the aggregation propensity of bacterial proteins is associated with their length, conformation, location, function, and abundance. The data are consistent with the predictions of other algorithms on different theoretical proteomes. CONCLUSIONS/SIGNIFICANCE Overall, the study suggests that the avoidance of protein aggregation in functional environments acts as a strong evolutionary constraint on polypeptide sequences in both prokaryotic and eukaryotic organisms.
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Affiliation(s)
- Natalia S. de Groot
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Salvador Ventura
- Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain
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