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Spudich JA, Nandwani N, Robert-Paganin J, Houdusse A, Ruppel KM. Reassessing the unifying hypothesis for hypercontractility caused by myosin mutations in hypertrophic cardiomyopathy. EMBO J 2024; 43:4139-4155. [PMID: 39192034 PMCID: PMC11445530 DOI: 10.1038/s44318-024-00199-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 07/12/2024] [Accepted: 07/18/2024] [Indexed: 08/29/2024] Open
Affiliation(s)
- James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Neha Nandwani
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Julien Robert-Paganin
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, F-75005, Paris, France
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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Wang H, Sun F. UNC-45A: A potential therapeutic target for malignant tumors. Heliyon 2024; 10:e31276. [PMID: 38803956 PMCID: PMC11128996 DOI: 10.1016/j.heliyon.2024.e31276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/31/2023] [Accepted: 05/14/2024] [Indexed: 05/29/2024] Open
Abstract
Uncoordinated mutant number-45 myosin chaperone A (UNC-45A), a protein highly conserved throughout evolution, is ubiquitously expressed in somatic cells. It is correlated with tumorigenesis, proliferation, metastasis, and invasion of multiple malignant tumors. The current understanding of the role of UNC-45A in tumor progression is mainly related to the regulation of non-muscle myosin II (NM-II). However, many studies have suggested that the mechanisms by which UNC-45A is involved in tumor progression are far greater than those of NM-II regulation. UNC-45A can also promote tumor cell proliferation by regulating checkpoint kinase 1 (ChK1) phosphorylation or the transcriptional activity of nuclear receptors, and induces chemoresistance to paclitaxel in tumor cells by destabilizing microtubule activity. In this review, we discuss the recent advances illuminating the role of UNC-45A in tumor progression. We also put forward therapeutic strategies targeting UNC-45A, in the hope of paving the way the development of UNC-45A-targeted therapies for patients with malignant tumors.
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Affiliation(s)
- Hong Wang
- School of Nursing, Binzhou Medical University, Yantai, 264003, PR China
| | - Fude Sun
- Department of Anesthesiology, Yantai Penglai Traditional Chinese Medicine Hospital, Yantai, 265699, PR China
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Almaas R, Atneosen-Åsegg M, Ytre-Arne ME, Melheim M, Sorte HS, Cízková D, Reims HM, Bezrouk A, Harrison SP, Strand J, Hermansen JU, Andersen SS, Eiklid KL, Mokrý J, Sullivan GJ, Stray-Pedersen A. Aagenaes syndrome/lymphedema cholestasis syndrome 1 is caused by a founder variant in the 5'-untranslated region of UNC45A. J Hepatol 2023; 79:945-954. [PMID: 37328071 DOI: 10.1016/j.jhep.2023.05.037] [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: 05/25/2022] [Revised: 05/12/2023] [Accepted: 05/21/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND & AIMS Lymphedema cholestasis syndrome 1 or Aagenaes syndrome is a condition characterized by neonatal cholestasis, lymphedema, and giant cell hepatitis. The genetic background of this autosomal recessive disease was unknown up to now. METHODS A total of 26 patients with Aagenaes syndrome and 17 parents were investigated with whole-genome sequencing and/or Sanger sequencing. PCR and western blot analyses were used to assess levels of mRNA and protein, respectively. CRISPR/Cas9 was used to generate the variant in HEK293T cells. Light microscopy, transmission electron microscopy and immunohistochemistry for biliary transport proteins were performed in liver biopsies. RESULTS One specific variant (c.-98G>T) in the 5'-untranslated region of Unc-45 myosin chaperone A (UNC45A) was identified in all tested patients with Aagenaes syndrome. Nineteen were homozygous for the c.-98G>T variant and seven were compound heterozygous for the variant in the 5'-untranslated region and an exonic loss-of-function variant in UNC45A. Patients with Aagenaes syndrome exhibited lower expression of UNC45A mRNA and protein than controls, and this was reproduced in a CRISPR/Cas9-created cell model. Liver biopsies from the neonatal period demonstrated cholestasis, paucity of bile ducts and pronounced formation of multinucleated giant cells. Immunohistochemistry revealed mislocalization of the hepatobiliary transport proteins BSEP (bile salt export pump) and MRP2 (multidrug resistance-associated protein 2). CONCLUSIONS c.-98G>T in the 5'-untranslated region of UNC45A is the causative genetic variant in Aagenaes syndrome. IMPACT AND IMPLICATIONS The genetic background of Aagenaes syndrome, a disease presenting with cholestasis and lymphedema in childhood, was unknown until now. A variant in the 5'-untranslated region of the Unc-45 myosin chaperone A (UNC45A) was identified in all tested patients with Aagenaes syndrome, providing evidence of the genetic background of the disease. Identification of the genetic background provides a tool for diagnosis of patients with Aagenaes syndrome before lymphedema is evident.
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Affiliation(s)
- Runar Almaas
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Paediatrics, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway; European Reference Network - Rare Liver.
| | | | - Mari Eknes Ytre-Arne
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Maria Melheim
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway; European Reference Network - Rare Liver
| | - Hanne Sørmo Sorte
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Dana Cízková
- Department of Histology and Embryology, Faculty of Medicine in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Henrik Mikael Reims
- European Reference Network - Rare Liver; Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Aleš Bezrouk
- Department of Medical Biophysics, Faculty of Medicine in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Sean Philip Harrison
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway; European Reference Network - Rare Liver
| | - Janne Strand
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Johanne Uthus Hermansen
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway
| | - Sofie Strøm Andersen
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway
| | | | - Jaroslav Mokrý
- Department of Histology and Embryology, Faculty of Medicine in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic
| | - Gareth John Sullivan
- Department of Pediatric Research, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Pb 4950, Nydalen, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway; European Reference Network - Rare Liver
| | - Asbjørg Stray-Pedersen
- European Reference Network - Rare Liver; Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
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4
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Brito C, Pereira JM, Mesquita FS, Cabanes D, Sousa S. Src-Dependent NM2A Tyrosine Phosphorylation Regulates Actomyosin Remodeling. Cells 2023; 12:1871. [PMID: 37508535 PMCID: PMC10377941 DOI: 10.3390/cells12141871] [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: 06/07/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Non-muscle myosin 2A (NM2A) is a key cytoskeletal enzyme that, along with actin, assembles into actomyosin filaments inside cells. NM2A is fundamental for cell adhesion and motility, playing important functions in different stages of development and during the progression of viral and bacterial infections. Phosphorylation events regulate the activity and the cellular localization of NM2A. We previously identified the tyrosine phosphorylation of residue 158 (pTyr158) in the motor domain of the NM2A heavy chain. This phosphorylation can be promoted by Listeria monocytogenes infection of epithelial cells and is dependent on Src kinase; however, its molecular role is unknown. Here, we show that the status of pTyr158 defines cytoskeletal organization, affects the assembly/disassembly of focal adhesions, and interferes with cell migration. Cells overexpressing a non-phosphorylatable NM2A variant or expressing reduced levels of Src kinase display increased stress fibers and larger focal adhesions, suggesting an altered contraction status consistent with the increased NM2A activity that we also observed. We propose NM2A pTyr158 as a novel layer of regulation of actomyosin cytoskeleton organization.
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Affiliation(s)
- Cláudia Brito
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal
- MCBiology PhD Program-Instituto de Ciências Biomédicas Abel Salazar-ICBAS, University of Porto, 4050-313 Porto, Portugal
| | - Joana M Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal
- MCBiology PhD Program-Instituto de Ciências Biomédicas Abel Salazar-ICBAS, University of Porto, 4050-313 Porto, Portugal
| | - Francisco S Mesquita
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal
| | - Didier Cabanes
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- IBMC, Instituto de Biologia Celular e Molecular, 4200-135 Porto, Portugal
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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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Liu C, Hao J, Yao LL, Wei M, Chen W, Yang Q, Li XD. Insect Sf9 cells are suitable for functional expression of insect, but not vertebrate, striated muscle myosin. Biochem Biophys Res Commun 2022; 635:259-266. [DOI: 10.1016/j.bbrc.2022.10.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 09/28/2022] [Accepted: 10/14/2022] [Indexed: 11/25/2022]
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Analysis of Plasmodium falciparum myosin B ATPase activity and structure in complex with the calmodulin-like domain of its light chain MLC-B. J Biol Chem 2022; 298:102634. [PMID: 36273584 PMCID: PMC9692044 DOI: 10.1016/j.jbc.2022.102634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
Myosin B (MyoB) is a class 14 myosin expressed in all invasive stages of the malaria parasite, Plasmodium falciparum. It is not associated with the glideosome complex that drives motility and invasion of host cells. During red blood cell invasion, MyoB remains at the apical tip of the merozoite but is no longer observed once invasion is completed. MyoB is not essential for parasite survival, but when it is knocked out, merozoites are delayed in the initial stages of red blood cell invasion, giving rise to a growth defect that correlates with reduced invasion success. Therefore, further characterization is needed to understand how MyoB contributes to parasite invasion. Here, we have expressed and purified functional MyoB with the help of parasite-specific chaperones Hsp90 and Unc45, characterized its binding to actin and its known light chain MLC-B using biochemical and biophysical methods and determined its low-resolution structure in solution using small angle X-ray scattering. In addition to MLC-B, we found that four other putative regulatory light chains bind to the MyoB IQ2 motif in vitro. The purified recombinant MyoB adopted the overall shape of a myosin, exhibited actin-activated ATPase activity, and moved actin filaments in vitro. Additionally, we determined that the ADP release rate was faster than the ATP turnover number, and thus, does not appear to be rate limiting. This, together with the observed high affinity to actin and the specific localization of MyoB, may point toward a role in tethering and/or force sensing during early stages of invasion.
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Kawana M, Spudich JA, Ruppel KM. Hypertrophic cardiomyopathy: Mutations to mechanisms to therapies. Front Physiol 2022; 13:975076. [PMID: 36225299 PMCID: PMC9548533 DOI: 10.3389/fphys.2022.975076] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/22/2022] [Indexed: 01/10/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) affects more than 1 in 500 people in the general population with an extensive burden of morbidity in the form of arrhythmia, heart failure, and sudden death. More than 25 years since the discovery of the genetic underpinnings of HCM, the field has unveiled significant insights into the primary effects of these genetic mutations, especially for the myosin heavy chain gene, which is one of the most commonly mutated genes. Our group has studied the molecular effects of HCM mutations on human β-cardiac myosin heavy chain using state-of-the-art biochemical and biophysical tools for the past 10 years, combining insights from clinical genetics and structural analyses of cardiac myosin. The overarching hypothesis is that HCM-causing mutations in sarcomere proteins cause hypercontractility at the sarcomere level, and we have shown that an increase in the number of myosin molecules available for interaction with actin is a primary driver. Recently, two pharmaceutical companies have developed small molecule inhibitors of human cardiac myosin to counteract the molecular consequences of HCM pathogenesis. One of these inhibitors (mavacamten) has recently been approved by the FDA after completing a successful phase III trial in HCM patients, and the other (aficamten) is currently being evaluated in a phase III trial. Myosin inhibitors will be the first class of medication used to treat HCM that has both robust clinical trial evidence of efficacy and that targets the fundamental mechanism of HCM pathogenesis. The success of myosin inhibitors in HCM opens the door to finding other new drugs that target the sarcomere directly, as we learn more about the genetics and fundamental mechanisms of this disease.
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Affiliation(s)
- Masataka Kawana
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States,Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - James A. Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States
| | - Kathleen M. Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, United States,*Correspondence: Kathleen M. Ruppel,
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Piper PW, Scott JE, Millson SH. UCS Chaperone Folding of the Myosin Head: A Function That Evolved before Animals and Fungi Diverged from a Common Ancestor More than a Billion Years Ago. Biomolecules 2022; 12:biom12081028. [PMID: 35892339 PMCID: PMC9331494 DOI: 10.3390/biom12081028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
The folding of the myosin head often requires a UCS (Unc45, Cro1, She4) domain-containing chaperone. Worms, flies, and fungi have just a single UCS protein. Vertebrates have two; one (Unc45A) which functions primarily in non-muscle cells and another (Unc45B) that is essential for establishing and maintaining the contractile apparatus of cardiac and skeletal muscles. The domain structure of these proteins suggests that the UCS function evolved before animals and fungi diverged from a common ancestor more than a billion years ago. UCS proteins of metazoans and apicomplexan parasites possess a tetratricopeptide repeat (TPR), a domain for direct binding of the Hsp70/Hsp90 chaperones. This, however, is absent in the UCS proteins of fungi and largely nonessential for the UCS protein function in Caenorhabditis elegans and zebrafish. The latter part of this review focusses on the TPR-deficient UCS proteins of fungi. While these are reasonably well studied in yeasts, there is little precise information as to how they might engage in interactions with the Hsp70/Hsp90 chaperones or might assist in myosin operations during the hyphal growth of filamentous fungi.
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Affiliation(s)
- Peter William Piper
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
- Correspondence: (P.W.P.); (S.H.M.)
| | | | - Stefan Heber Millson
- School of Life Sciences, University of Lincoln, Lincoln LN6 7DL, UK;
- Correspondence: (P.W.P.); (S.H.M.)
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Ojima K, Kigaki M, Ichimura E, Suzuki T, Kobayashi K, Muroya S, Nishimura T. Endogenous slow and fast myosin dynamics in myofibers isolated from mice expressing GFP-Myh7 and Kusabira Orange-Myh1. Am J Physiol Cell Physiol 2022; 323:C520-C535. [PMID: 35759444 DOI: 10.1152/ajpcell.00415.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle consists of slow and fast myofibers in which different myosin isoforms are expressed. Approximately 300 myosins form a single thick filament in the myofibrils, where myosin is continuously exchanged. However, endogenous slow and fast myosin dynamics have not been fully understood. To elucidate those dynamics, here we generated mice expressing green fluorescence protein-tagged slow myosin heavy chain (GFP-Myh7) and Kusabira Orange fluorescence protein-tagged fast myosin heavy chain (KuO-Myh1). First, these mice enabled us to distinguish between GFP- and KuO-myofibers under fluorescence microscopy: GFP-Myh7 and KuO-Myh1 were exclusively expressed in slow myofibers and fast myofibers, respectively. Next, to monitor endogenous myosin dynamics, fluorescence recovery after photobleaching (FRAP) was conducted. The mobile fraction (Mf) of GFP-Myh7 and that of KuO-Myh1 were almost constant values independent of the regions of the myofibers and the muscle portions where the myofibers were isolated. Intriguingly, proteasome inhibitor treatment significantly decreased the Mf in GFP-Myh7 but not in KuO-Myh1 myofibers, indicating that the response to a disturbance in protein turnover depended on muscle fiber type. Taken together, the present results indicated that the mice we generated are promising tools not only for distinguishing between GFP- and KuO-myofibers but also for studying the dynamics of endogenous myosin isoforms by live-cell fluorescence imaging.
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Affiliation(s)
- Koichi Ojima
- Muscle Biology Research Unit, Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, Japan
| | - Masahiro Kigaki
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Emi Ichimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Takahiro Suzuki
- Laboratory of Muscle and Meat Science, Department of Animal and Marine Bioresource Sciences, Faculty of Agriculture, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Ken Kobayashi
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Susumu Muroya
- Muscle Biology Research Unit, Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, Japan
| | - Takanori Nishimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
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11
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Lechuga S, Cartagena‐Rivera AX, Khan A, Crawford BI, Narayanan V, Conway DE, Lehtimäki J, Lappalainen P, Rieder F, Longworth MS, Ivanov AI. A myosin chaperone, UNC-45A, is a novel regulator of intestinal epithelial barrier integrity and repair. FASEB J 2022; 36:e22290. [PMID: 35344227 PMCID: PMC9044500 DOI: 10.1096/fj.202200154r] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 01/01/2023]
Abstract
The actomyosin cytoskeleton serves as a key regulator of the integrity and remodeling of epithelial barriers by controlling assembly and functions of intercellular junctions and cell-matrix adhesions. Although biochemical mechanisms that regulate the activity of non-muscle myosin II (NM-II) in epithelial cells have been extensively investigated, little is known about assembly of the contractile myosin structures at the epithelial adhesion sites. UNC-45A is a cytoskeletal chaperone that is essential for proper folding of NM-II heavy chains and myofilament assembly. We found abundant expression of UNC-45A in human intestinal epithelial cell (IEC) lines and in the epithelial layer of the normal human colon. Interestingly, protein level of UNC-45A was decreased in colonic epithelium of patients with ulcerative colitis. CRISPR/Cas9-mediated knock-out of UNC-45A in HT-29cf8 and SK-CO15 IEC disrupted epithelial barrier integrity, impaired assembly of epithelial adherence and tight junctions and attenuated cell migration. Consistently, decreased UNC-45 expression increased permeability of the Drosophila gut in vivo. The mechanisms underlying barrier disruptive and anti-migratory effects of UNC-45A depletion involved disorganization of the actomyosin bundles at epithelial junctions and the migrating cell edge. Loss of UNC-45A also decreased contractile forces at apical junctions and matrix adhesions. Expression of deletion mutants revealed roles for the myosin binding domain of UNC-45A in controlling IEC junctions and motility. Our findings uncover a novel mechanism that regulates integrity and restitution of the intestinal epithelial barrier, which may be impaired during mucosal inflammation.
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Affiliation(s)
- Susana Lechuga
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA
| | - Alexander X. Cartagena‐Rivera
- Section on MechanobiologyNational Institute of Biomedical Imaging and BioengineeringNational Institutes of HealthBethesdaMarylandUSA
| | - Afshin Khan
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA
| | - Bert I. Crawford
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA
| | - Vani Narayanan
- Department of Biomedical EngineeringVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Daniel E. Conway
- Department of Biomedical EngineeringVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Jaakko Lehtimäki
- Institute of Biotechnology and Helsinki Institute of Life SciencesUniversity of HelsinkiHelsinkiFinland
| | - Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life SciencesUniversity of HelsinkiHelsinkiFinland
| | - Florian Rieder
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA,Department of Gastroenterology, Hepatology and Nutrition, Digestive Diseases and Surgery InstituteCleveland Clinic FoundationClevelandOhioUSA
| | - Michelle S. Longworth
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA
| | - Andrei I. Ivanov
- Department of Inflammation and ImmunityLerner Research InstituteCleveland Clinic FoundationClevelandOhioUSA
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Li Q, Zhou Z, Sun Y, Sun C, Klappe K, van IJzendoorn SC. A Functional Relationship Between UNC45A and MYO5B Connects Two Rare Diseases With Shared Enteropathy. Cell Mol Gastroenterol Hepatol 2022; 14:295-310. [PMID: 35421597 PMCID: PMC9218578 DOI: 10.1016/j.jcmgh.2022.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/05/2022] [Accepted: 04/05/2022] [Indexed: 01/20/2023]
Abstract
BACKGROUND & AIMS UNC45A is a myosin (co-)chaperone, and mutations in the UNC45A gene were recently identified in osteo-oto-hepato-enteric (O2HE) syndrome patients presenting with congenital diarrhea and intrahepatic cholestasis. Congenital diarrhea and intrahepatic cholestasis are also the prime symptoms in patients with microvillus inclusion disease (MVID) and mutations in MYO5B, encoding the recycling endosome-associated myosin Vb. The aim of this study was to determine whether UNC45A and myosin Vb are functionally linked. METHODS CRISPR-Cas9 gene editing and site-directed mutagenesis were performed with intestinal epithelial and hepatocellular cell lines, followed by Western blotting, quantitative polymerase chain reaction, and scanning electron and/or confocal fluorescence microscopy to determine the relationship between (mutants of) UNC45A and myosin Vb. RESULTS UNC45A depletion in intestinal and hepatic cells reduced myosin Vb protein expression, and in intestinal epithelial cells, it affected 2 myosin Vb-dependent processes that underlie MVID pathogenesis: rat sarcoma-associated binding protein (RAB)11A-positve recycling endosome positioning and microvilli development. Reintroduction of UNC45A in UNC45A-depleted cells restored myosin Vb expression, and reintroduction of UNC45A or myosin Vb, but not the O2HE patient UNC45A-c.1268T>A variant, restored recycling endosome positioning and microvilli development. The O2HE patient-associated p.V423D substitution, encoded by the UNC45A-c.1268T>A variant, impaired UNC45A protein stability but as such not the ability of UNC45A to promote myosin Vb expression and microvilli development. CONCLUSIONS A functional relationship exists between UNC45A and myosin Vb, thereby connecting 2 rare congenital diseases with overlapping enteropathy at the molecular level. Protein instability rather than functional impairment underlies the pathogenicity of the O2HE syndrome-associated UNC45A-p.V423D mutation.
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Affiliation(s)
| | | | | | | | | | - Sven C.D. van IJzendoorn
- Correspondence Address correspondence to: Sven C. D. van IJzendoorn, PhD, Department of Biomedical Sciences of Cells & Systems, Section Molecular Cell Biology, University of Groningen, University Medical Center, Antonius Deusinglaan 1, 9713 AV, Groningen, the Netherlands.
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13
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Richardson L, Wang D, Hughes R, Johnson CA, Peckham M. RNA-Seq analysis of a Pax3-expressing myoblast clone in-vitro and effect of culture surface stiffness on differentiation. Sci Rep 2022; 12:2841. [PMID: 35181706 PMCID: PMC8857316 DOI: 10.1038/s41598-022-06795-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 02/02/2022] [Indexed: 11/09/2022] Open
Abstract
Skeletal muscle satellite cells cultured on soft surfaces (12 kPa) show improved differentiation than cells cultured on stiff surfaces (approximately 100 kPa). To better understand the reasons for this, we performed an RNA-Seq analysis for a single satellite cell clone (C1F) derived from the H2kb-tsA58 immortomouse, which differentiates into myotubes under tightly regulated conditions (withdrawal of ɣ-interferon, 37 °C). The largest change in overall gene expression occurred at day 1, as cells switched from proliferation to differentiation. Surprisingly, further analysis showed that proliferating C1F cells express Pax3 and not Pax7, confirmed by immunostaining, yet their subsequent differentiation into myotubes is normal, and enhanced on softer surfaces, as evidenced by significantly higher expression levels of myogenic regulatory factors, sarcomeric genes, enhanced fusion and improved myofibrillogenesis. Levels of mRNA encoding extracellular matrix structural constituents and related genes were consistently upregulated on hard surfaces, suggesting that a consequence of differentiating satellite cells on hard surfaces is that they attempt to manipulate their niche prior to differentiating. This comprehensive RNA-Seq dataset will be a useful resource for understanding Pax3 expressing cells.
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Affiliation(s)
- Louise Richardson
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Dapeng Wang
- LeedsOmics, University of Leeds, Leeds, LS2 9JT, UK.,Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Ruth Hughes
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Colin A Johnson
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Michelle Peckham
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK.
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14
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Wang T, Liu Y, Mei L, Cui T, Wei D, Chen Y, Zhang X, Gao L, Zhang S, Guo L, Yang P, Niu X. Proteins in plasma as a potential biomarkers diagnostic for pelvic organ prolapse. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1117. [PMID: 34430558 PMCID: PMC8350695 DOI: 10.21037/atm-21-1607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/12/2021] [Indexed: 11/18/2022]
Abstract
Background Pelvic organ prolapse (POP) is the most common and widespread type of female pelvic floor dysfunction disease (PFD). At present, the diagnosis of POP is mainly based on a complicated systematic evaluation of the clinical phenotype, medical history, and relevant functional examinations. Rapid and simple tests that are based on biochemical biomarkers that surpass the sensitivity and specificity of the current methods for the diagnosis of POP will greatly facilitate the timely diagnosis and treatment of women with POP. Methods A protein array was used to screen plasma samples collected from healthy controls and women with POP. Enzyme-linked immunosorbent assays (ELISAs) were used to determine the levels of three novel and potentially useful analytes: heat shock protein 10 (HSP10), zinc finger CCCH domain-containing protein 8 (ZC3H8), and unc-45 myosin chaperone A (UNC45A). We then determined the diagnostic value of each of these analytes as potential diagnostic biomarkers for clinical application. Results The mean levels of HSP10, ZC3H8, and UNC45A, were lower in the plasma samples from 76 patients with POP than in 56 samples from healthy controls (P<0.05). Comparisons between patients with POP and healthy controls demonstrated the sensitivity and specificity of HSP10 (73.7% and 71.4%), ZC3H8 (71.1% and 62.5%), and UNC45A (70.7% and 62.5%). Conclusions Analysis indicated that plasma levels of HSP10, ZC3H8, and UNC45A, are sensitive and specific biomarkers for the diagnosis of POP.
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Affiliation(s)
- Tao Wang
- Center for Translational Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yuqing Liu
- Center for Translational Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Ling Mei
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Tao Cui
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Dongmei Wei
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yueyue Chen
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Xiaoli Zhang
- Center for Translational Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Linbo Gao
- Center for Translational Medicine, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Shihong Zhang
- Health Management Center, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Lanfang Guo
- Health Management Center, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Pei Yang
- Health Management Center, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Xiaoyu Niu
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
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15
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Shi K, Yang L, Du X, Guo D, Xue L. Molecular chaperone Hsp90 protects KCBP from degradation by proteasome in Dunaliella salina cells. Folia Microbiol (Praha) 2021; 66:949-957. [PMID: 34240332 DOI: 10.1007/s12223-021-00897-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/01/2021] [Indexed: 11/26/2022]
Abstract
Kinesin-like calmodulin-binding protein (KCBP) is a unique kinesin with half kinesin and half myosin, with kinesin motor domain at C-terminus and myosin tail homology region 4 (MyTH4) and band 4.1, ezrin, radixin, moesin (FERM) domains at N-terminus. The special structure endows KCBP multi-intracellular functions, including cell division, trichome morphogenesis in plants, and flagellar function in algae. However, little is known about the molecular mechanism underlying these functions. Here, we identified a molecular chaperone Hsp90 as a novel binding partner with KCBP in Dunaliella salina using a yeast two-hybrid screen. Further analysis showed that Hsp90 interacted with both the N-terminal and C-terminal of DsKCBP. Since Hsp90 was involved in the stability and proteolytic turnover of numerous proteins, whether Hsp90 regulated the degradation of DsKCBP was investigated. Our results showed that both Hsp90 and DsKCBP presented in the purified proteasome, and the interaction of DsKCBP-Hsp90 was inhibited upon Hsp90 inhibitor geldanamycin treatment. The level of DsKCBP proteins was diminished remarkably indicating that the disassociation of DsKCBP from Hsp90 accelerated the degradation of the former. Furthermore, immunofluorescence results showed that the localization of DsKCBP at basal body and flagella was disappeared by Hsp90 inhibition. The increased mRNA level of DsKCBP during flagellar assembly was not obvious by geldanamycin treatment. These data provided evidence that Hsp90 protected DsKCBP from degradation by proteasome and was involved in the role of DsKCBP in flagellar assembly.
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Affiliation(s)
- Ke Shi
- Department of Biochemistry and Molecular Biology, Henan Medical College, Zhengzhou, Henan, China.
- Laboratory for Cell Biology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, China.
| | - Liang Yang
- Department of Microbiology and Immunology and Medicine, Henan Medical College, Zhengzhou, Henan, China
| | - Xiuhong Du
- Department of Biochemistry and Molecular Biology, Henan Medical College, Zhengzhou, Henan, China
| | - Dan Guo
- Department of Biochemistry and Molecular Biology, Henan Medical College, Zhengzhou, Henan, China
| | - Lexun Xue
- Laboratory for Cell Biology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, China.
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16
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Schmauder L, Richter K. hsp-90 and unc-45 depletion induce characteristic transcriptional signatures in coexpression cliques of C. elegans. Sci Rep 2021; 11:12852. [PMID: 34145311 PMCID: PMC8213770 DOI: 10.1038/s41598-021-91690-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/21/2021] [Indexed: 11/09/2022] Open
Abstract
Nematode development is characterized by progression through several larval stages. Thousands of genes were found in large scale RNAi-experiments to block this development at certain steps, two of which target the molecular chaperone HSP-90 and its cofactor UNC-45. Aiming to define the cause of arrest, we here investigate the status of nematodes after treatment with RNAi against hsp-90 and unc-45 by employing an in-depth transcriptional analysis of the arrested larvae. To identify misregulated transcriptional units, we calculate and validate genome-wide coexpression cliques covering the entire nematode genome. We define 307 coexpression cliques and more than half of these can be related to organismal functions by GO-term enrichment, phenotype enrichment or tissue enrichment analysis. Importantly, hsp-90 and unc-45 RNAi induce or repress many of these cliques in a coordinated manner, and then several specifically regulated cliques are observed. To map the developmental state of the arrested nematodes we define the expression behaviour of each of the cliques during development from embryo to adult nematode. hsp-90 RNAi can be seen to arrest development close to the L4 larval stage with further deviations in daf-16 regulated genes. unc-45 RNAi instead leads to arrested development at young adult stage prior to the programmatic downregulation of sperm-cell specific genes. In both cases processes can be defined to be misregulated upon depletion of the respective chaperone. With most of the defined gene cliques showing concerted behaviour at some stage of development from embryo to late adult, the “clique map” together with the clique-specific GO-terms, tissue and phenotype assignments will be a valuable tool in understanding concerted responses on the genome-wide level in Caenorhabditis elegans.
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Affiliation(s)
- Lukas Schmauder
- Center for integrated protein research at the Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Klaus Richter
- Center for integrated protein research at the Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, 85748, Garching, Germany.
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17
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Tumane RG, Thakkar L, Pingle SK, Jain RK, Jawade AA, Raje DV. Expression of serum proteins in noise induced hearing loss workers of mining based industry. J Proteomics 2021; 240:104185. [PMID: 33737237 DOI: 10.1016/j.jprot.2021.104185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/28/2021] [Accepted: 03/04/2021] [Indexed: 12/20/2022]
Abstract
Noise Induced Hearing Loss (NIHL) is caused by excessive noise exposure due to occupational activities thus affects communication and quality of life. Prolonged occupational and environmental exposure to loud noise damages key molecules present in the micro-machinery of the ear which are required for the mechano-electrical transduction of sound waves in cochlea. Specific proteins are known to be associated with hearing loss and related structural and functional disabilities in the human inner, outer hair cells and cochlea. Rationale of this study was to identify the cochlear proteins associated with the pathophysiology of NIHL using proteomic approaches in mining based industrial workers. Total (n = 210) samples were collected from mining based industrial workers of central India. Subjects were categorized based on audiometric analysis. Proteome changes of the host serum were investigated using one and two-dimensional electrophoresis in combination with LC-MS/MS and MALDI-TOF-MS. Up-regulated 46 cochlear proteins among confirmed NIHL cases were identified by MASCOT. Shrinkage discriminant analysis provided top 25 discriminating feature proteins namely myosin, transthyretin, SERPIN, CCDC50, enkurin, transferin etc. The identified potential proteins may be used as biomarkers for early detection and to understand the pathogenic mechanism of NIHL. Evaluation of these biomarkers in follow-up cases may further aid in improving NIHL diagnosis. SIGNIFICANCE: Human proteome study in Noise Induced Hearing Loss (NIHL) cases has not been published till date. This study represents most comprehensive proteomic analysis in NIHL cases taken from Indian mine workers. The identified key twenty-five discriminating feature proteins which are upregulated when an individual develops (or is in stage of development of) NIHL, provides insights into the potential roles of these varied proteins in disease progression. The proteins thus identified by proteomic approach may be used as early diagnostic biomarker to predict the occurrence of disease at very early stage.
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Affiliation(s)
- Rajani G Tumane
- Department of Biochemistry, National Institute of Miners' Health, JNARDDC Campus, Wadi, Nagpur 440023, Maharashtra, India
| | - Lucky Thakkar
- Department of Biochemistry, National Institute of Miners' Health, JNARDDC Campus, Wadi, Nagpur 440023, Maharashtra, India
| | - Shubhangi K Pingle
- Department of Biochemistry, National Institute of Miners' Health, JNARDDC Campus, Wadi, Nagpur 440023, Maharashtra, India.
| | - Ruchika K Jain
- Department of Biochemistry, National Institute of Miners' Health, JNARDDC Campus, Wadi, Nagpur 440023, Maharashtra, India
| | - Aruna A Jawade
- Department of Biochemistry, National Institute of Miners' Health, JNARDDC Campus, Wadi, Nagpur 440023, Maharashtra, India
| | - Dhananjay V Raje
- MDS Analytics, First Floor Sakar Enclave, Plot No. 127, Shankar Nagar, Nagpur, Maharashtra, India
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18
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Spectrum of MYO7A Mutations in an Indigenous South African Population Further Elucidates the Nonsyndromic Autosomal Recessive Phenotype of DFNB2 to Include Both Homozygous and Compound Heterozygous Mutations. Genes (Basel) 2021; 12:genes12020274. [PMID: 33671976 PMCID: PMC7919343 DOI: 10.3390/genes12020274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 11/17/2022] Open
Abstract
MYO7A gene encodes unconventional myosin VIIA, which, when mutated, causes a phenotypic spectrum ranging from recessive hearing loss DFNB2 to deaf-blindness, Usher Type 1B (USH1B). MYO7A mutations are reported in nine DFNB2 families to date, none from sub-Saharan Africa.In DNA, from a cohort of 94 individuals representing 92 families from the Limpopo province of South Africa, eight MYO7A variations were detected among 10 individuals. Family studies identified homozygous and compound heterozygous mutations in 17 individuals out of 32 available family members. Four mutations were novel, p.Gly329Asp, p.Arg373His, p.Tyr1780Ser, and p.Pro2126Leufs*5. Two variations, p.Ser617Pro and p.Thr381Met, previously listed as of uncertain significance (ClinVar), were confirmed to be pathogenic. The identified mutations are predicted to interfere with the conformational properties of myosin VIIA through interruption or abrogation of multiple interactions between the mutant and neighbouring residues. Specifically, p.Pro2126Leufs*5, is predicted to abolish the critical site for the interactions between the tail and the motor domain essential for the autoregulation, leaving a non-functional, unregulated protein that causes hearing loss. We have identified MYO7A as a possible key deafness gene among indigenous sub-Saharan Africans. The spectrum of MYO7A mutations in this South African population points to DFNB2 as a specific entity that may occur in a homozygous or in a compound heterozygous state.
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19
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Jiang F, Takagi Y, Shams A, Heissler SM, Friedman TB, Sellers JR, Bird JE. The ATPase mechanism of myosin 15, the molecular motor mutated in DFNB3 human deafness. J Biol Chem 2021; 296:100243. [PMID: 33372036 PMCID: PMC7948958 DOI: 10.1074/jbc.ra120.014903] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 12/23/2020] [Accepted: 12/28/2020] [Indexed: 11/18/2022] Open
Abstract
Cochlear hair cells each possess an exquisite bundle of actin-based stereocilia that detect sound. Unconventional myosin 15 (MYO15) traffics and delivers critical molecules required for stereocilia development and thus is essential for building the mechanosensory hair bundle. Mutations in the human MYO15A gene interfere with stereocilia trafficking and cause hereditary hearing loss, DFNB3, but the impact of these mutations is not known, as MYO15 itself is poorly characterized. To learn more, we performed a kinetic study of the ATPase motor domain to characterize its mechanochemical cycle. Using the baculovirus-Sf9 system, we purified a recombinant minimal motor domain (S1) by coexpressing the mouse MYO15 ATPase, essential and regulatory light chains that bind its IQ domains, and UNC45 and HSP90A chaperones required for correct folding of the ATPase. MYO15 purified with either UNC45A or UNC45B coexpression had similar ATPase activities (kcat = ∼ 6 s-1 at 20 °C). Using stopped-flow and quenched-flow transient kinetic analyses, we measured the major rate constants describing the ATPase cycle, including ATP, ADP, and actin binding; hydrolysis; and phosphate release. Actin-attached ADP release was the slowest measured transition (∼12 s-1 at 20 °C), although this did not rate-limit the ATPase cycle. The kinetic analysis shows the MYO15 motor domain has a moderate duty ratio (∼0.5) and weak thermodynamic coupling between ADP and actin binding. These findings are consistent with MYO15 being kinetically adapted for processive motility when oligomerized. Our kinetic characterization enables future studies into how deafness-causing mutations affect MYO15 and disrupt stereocilia trafficking necessary for hearing.
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Affiliation(s)
- Fangfang Jiang
- Department of Pharmacology and Therapeutics, and the Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Yasuharu Takagi
- Laboratory of Molecular Physiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Arik Shams
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA
| | - Sarah M Heissler
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA
| | - James R Sellers
- Laboratory of Molecular Physiology, Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jonathan E Bird
- Department of Pharmacology and Therapeutics, and the Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA.
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20
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Edkins AL, Boshoff A. General Structural and Functional Features of Molecular Chaperones. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:11-73. [PMID: 34569020 DOI: 10.1007/978-3-030-78397-6_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Molecular chaperones are a group of structurally diverse and highly conserved ubiquitous proteins. They play crucial roles in facilitating the correct folding of proteins in vivo by preventing protein aggregation or facilitating the appropriate folding and assembly of proteins. Heat shock proteins form the major class of molecular chaperones that are responsible for protein folding events in the cell. This is achieved by ATP-dependent (folding machines) or ATP-independent mechanisms (holders). Heat shock proteins are induced by a variety of stresses, besides heat shock. The large and varied heat shock protein class is categorised into several subfamilies based on their sizes in kDa namely, small Hsps (HSPB), J domain proteins (Hsp40/DNAJ), Hsp60 (HSPD/E; Chaperonins), Hsp70 (HSPA), Hsp90 (HSPC), and Hsp100. Heat shock proteins are localised to different compartments in the cell to carry out tasks specific to their environment. Most heat shock proteins form large oligomeric structures, and their functions are usually regulated by a variety of cochaperones and cofactors. Heat shock proteins do not function in isolation but are rather part of the chaperone network in the cell. The general structural and functional features of the major heat shock protein families are discussed, including their roles in human disease. Their function is particularly important in disease due to increased stress in the cell. Vector-borne parasites affecting human health encounter stress during transmission between invertebrate vectors and mammalian hosts. Members of the main classes of heat shock proteins are all represented in Plasmodium falciparum, the causative agent of cerebral malaria, and they play specific functions in differentiation, cytoprotection, signal transduction, and virulence.
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Affiliation(s)
- Adrienne Lesley Edkins
- Biomedical Biotechnology Research Unit (BioBRU), Department of Biochemistry and Microbiology, Rhodes University, Makhanda/Grahamstown, South Africa.
- Rhodes University, Makhanda/Grahamstown, South Africa.
| | - Aileen Boshoff
- Rhodes University, Makhanda/Grahamstown, South Africa.
- Biotechnology Innovation Centre, Rhodes University, Makhanda/Grahamstown, South Africa.
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21
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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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22
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Adhikari AS, Trivedi DV, Sarkar SS, Song D, Kooiker KB, Bernstein D, Spudich JA, Ruppel KM. β-Cardiac myosin hypertrophic cardiomyopathy mutations release sequestered heads and increase enzymatic activity. Nat Commun 2019; 10:2685. [PMID: 31213605 PMCID: PMC6582153 DOI: 10.1038/s41467-019-10555-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) affects 1 in 500 people and leads to hyper-contractility of the heart. Nearly 40 percent of HCM-causing mutations are found in human β-cardiac myosin. Previous studies looking at the effect of HCM mutations on the force, velocity and ATPase activity of the catalytic domain of human β-cardiac myosin have not shown clear trends leading to hypercontractility at the molecular scale. Here we present functional data showing that four separate HCM mutations located at the myosin head-tail (R249Q, H251N) and head-head (D382Y, R719W) interfaces of a folded-back sequestered state referred to as the interacting heads motif (IHM) lead to a significant increase in the number of heads functionally accessible for interaction with actin. These results provide evidence that HCM mutations can modulate myosin activity by disrupting intramolecular interactions within the proposed sequestered state, which could lead to hypercontractility at the molecular level. Hypertrophic cardiomyopathy (HCM) leads to hyper-contractility of the heart and is often caused by mutations in human β-cardiac myosin. Here authors show that four separate β-cardiac myosin mutations can modulate myosin activity by disrupting intramolecular interactions.
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Affiliation(s)
- Arjun S Adhikari
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA
| | - Darshan V Trivedi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA
| | - Saswata S Sarkar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA
| | - Dan Song
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA
| | - Kristina B Kooiker
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA.,Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Daniel Bernstein
- Stanford Cardiovascular Institute, 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. .,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA.
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA. .,Stanford Cardiovascular Institute, Stanford, CA, 94305, USA. .,Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, 94305, USA.
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23
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Ghosh A, Dai Y, Biswas P, Stuehr DJ. Myoglobin maturation is driven by the hsp90 chaperone machinery and by soluble guanylyl cyclase. FASEB J 2019; 33:9885-9896. [PMID: 31170354 DOI: 10.1096/fj.201802793rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Myoglobin (Mb) maturation involves heme incorporation as a final step. We investigated a role for heat shock protein (hsp) 90 in Mb maturation in C2C12 skeletal muscle myoblasts and cell lines. We found the following: 1) Hsp90 directly interacts preferentially with heme-free Mb both in purified form and in cells. 2) Hsp90 drives heme insertion into apoprotein-Mb in an ATP-dependent process. 3) During differentiation of C2C12 myoblasts into myotubes, the apo-Mb-hsp90 complex associates with 5 cell cochaperons, Hsp70, activator of hsp90 ATPase protein 1 (Aha1), alanyl-tRNA synthetase domain containing 1 (Aarsd1), cell division cycle 37 (Cdc37), and stress induced phosphoprotein 1 (STIP1) in a pattern that is consistent with their enabling Mb maturation. 4) Mb heme insertion was significantly increased in cells that had a functional soluble guanylyl cyclase (sGC)-cGMP signaling pathway and was diminished upon small interfering RNA knockdown of sGCβ1 or upon overexpression of a phosphodiesterase to prevent cGMP buildup. Together, our findings suggest that hsp90 works in concert with cochaperons (Hsp70, Aha1, Aarsd1, STIP1, and Cdc37) and an active sGC-cGMP signaling pathway to promote heme insertion into immature apo-Mb, and thus generate functional Mb during muscle myotube formation. This fills gaps in our understanding and suggests new ways to potentially control these processes.-Ghosh, A., Dai, Y., Biswas, P., Stuehr, D. J. Myoglobin maturation is driven by the hsp90 chaperone machinery and by soluble guanylyl cyclase.
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Affiliation(s)
- Arnab Ghosh
- Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio, USA
| | - Yue Dai
- Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio, USA
| | - Pranjal Biswas
- Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio, USA
| | - Dennis J Stuehr
- Department of Inflammation and Immunity, Lerner Research Institute, The Cleveland Clinic, Cleveland, Ohio, USA
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24
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Ojima K. Myosin: Formation and maintenance of thick filaments. Anim Sci J 2019; 90:801-807. [PMID: 31134719 PMCID: PMC6618170 DOI: 10.1111/asj.13226] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/27/2019] [Accepted: 04/18/2019] [Indexed: 12/17/2022]
Abstract
Skeletal muscle consists of bundles of myofibers containing millions of myofibrils, each of which is formed of longitudinally aligned sarcomere structures. Sarcomeres are the minimum contractile unit, which mainly consists of four components: Z‐bands, thin filaments, thick filaments, and connectin/titin. The size and shape of the sarcomere component is strictly controlled. Surprisingly, skeletal muscle cells not only synthesize a series of myofibrillar proteins but also regulate the assembly of those proteins into the sarcomere structures. However, authentic sarcomere structures cannot be reconstituted by combining purified myofibrillar proteins in vitro, therefore there must be an elaborate mechanism ensuring the correct formation of myofibril structure in skeletal muscle cells. This review discusses the role of myosin, a main component of the thick filament, in thick filament formation and the dynamics of myosin in skeletal muscle cells. Changes in the number of myofibrils in myofibers can cause muscle hypertrophy or atrophy. Therefore, it is important to understand the fundamental mechanisms by which myofibers control myofibril formation at the molecular level to develop approaches that effectively enhance muscle growth in animals.
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Affiliation(s)
- Koichi Ojima
- Muscle Biology Research Unit, Division of Animal Products Research, National Institute of Livestock and Grassland Science, NARO, Tsukuba, Japan
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25
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Mooneyham A, Iizuka Y, Yang Q, Coombes C, McClellan M, Shridhar V, Emmings E, Shetty M, Chen L, Ai T, Meints J, Lee MK, Gardner M, Bazzaro M. UNC-45A Is a Novel Microtubule-Associated Protein and Regulator of Paclitaxel Sensitivity in Ovarian Cancer Cells. Mol Cancer Res 2019; 17:370-383. [PMID: 30322860 PMCID: PMC6359974 DOI: 10.1158/1541-7786.mcr-18-0670] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/11/2018] [Accepted: 10/02/2018] [Indexed: 12/14/2022]
Abstract
UNC-45A, a highly conserved member of the UCS (UNC45A/CRO1/SHE4P) protein family of cochaperones, plays an important role in regulating cytoskeletal-associated functions in invertebrates and mammalian cells, including cytokinesis, exocytosis, cell motility, and neuronal development. Here, for the first time, UNC-45A is demonstrated to function as a mitotic spindle-associated protein that destabilizes microtubules (MT) activity. Using in vitro biophysical reconstitution and total internal reflection fluorescence microscopy analysis, we reveal that UNC-45A directly binds to taxol-stabilized MTs in the absence of any additional cellular cofactors or other MT-associated proteins and acts as an ATP-independent MT destabilizer. In cells, UNC-45A binds to and destabilizes mitotic spindles, and its depletion causes severe defects in chromosome congression and segregation. UNC-45A is overexpressed in human clinical specimens from chemoresistant ovarian cancer and that UNC-45A-overexpressing cells resist chromosome missegregation and aneuploidy when treated with clinically relevant concentrations of paclitaxel. Lastly, UNC-45A depletion exacerbates paclitaxel-mediated stabilizing effects on mitotic spindles and restores sensitivity to paclitaxel. IMPLICATIONS: These findings reveal novel and significant roles for UNC-45A in regulation of cytoskeletal dynamics, broadening our understanding of the basic mechanisms regulating MT stability and human cancer susceptibility to paclitaxel, one of the most widely used chemotherapy agents for the treatment of human cancers.
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Affiliation(s)
- Ashley Mooneyham
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women’s Heath, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yoshie Iizuka
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women’s Heath, University of Minnesota, Minneapolis, MN 55455, USA
| | - Qing Yang
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Courtney Coombes
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Mark McClellan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Vijayalakshmi Shridhar
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Edith Emmings
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women’s Heath, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mihir Shetty
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women’s Heath, University of Minnesota, Minneapolis, MN 55455, USA
| | - Liqiang Chen
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN 55455 USA
| | - Teng Ai
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN 55455 USA
| | - Joyce Meints
- Department of Neuroscience, University of Minnesota Minneapolis, MN 55455 USA
| | - Michael K Lee
- Department of Neuroscience, University of Minnesota Minneapolis, MN 55455 USA
| | - Melissa Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Martina Bazzaro
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women’s Heath, University of Minnesota, Minneapolis, MN 55455, USA,,Corresponding author: Martina Bazzaro, Masonic Cancer Center, 420 Delaware Street S.E, Room 490, Minneapolis, Minnesota 55455, Tel: 612-6252889, Fax: 612-626-0665,
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26
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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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27
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Carlisle C, Prill K, Pilgrim D. Chaperones and the Proteasome System: Regulating the Construction and Demolition of Striated Muscle. Int J Mol Sci 2017; 19:E32. [PMID: 29271938 PMCID: PMC5795982 DOI: 10.3390/ijms19010032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 11/28/2017] [Accepted: 12/18/2017] [Indexed: 12/21/2022] Open
Abstract
Protein folding factors (chaperones) are required for many diverse cellular functions. In striated muscle, chaperones are required for contractile protein function, as well as the larger scale assembly of the basic unit of muscle, the sarcomere. The sarcomere is complex and composed of hundreds of proteins and the number of proteins and processes recognized to be regulated by chaperones has increased dramatically over the past decade. Research in the past ten years has begun to discover and characterize the chaperones involved in the assembly of the sarcomere at a rapid rate. Because of the dynamic nature of muscle, wear and tear damage is inevitable. Several systems, including chaperones and the ubiquitin proteasome system (UPS), have evolved to regulate protein turnover. Much of our knowledge of muscle development focuses on the formation of the sarcomere but recent work has begun to elucidate the requirement and role of chaperones and the UPS in sarcomere maintenance and disease. This review will cover the roles of chaperones in sarcomere assembly, the importance of chaperone homeostasis and the cooperation of chaperones and the UPS in sarcomere integrity and disease.
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Affiliation(s)
- Casey Carlisle
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Kendal Prill
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Dave Pilgrim
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
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28
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Lehtimäki JI, Fenix AM, Kotila TM, Balistreri G, Paavolainen L, Varjosalo M, Burnette DT, Lappalainen P. UNC-45a promotes myosin folding and stress fiber assembly. J Cell Biol 2017; 216:4053-4072. [PMID: 29055011 PMCID: PMC5716280 DOI: 10.1083/jcb.201703107] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/28/2017] [Accepted: 09/19/2017] [Indexed: 12/15/2022] Open
Abstract
Contractile actomyosin bundles, stress fibers, are crucial for adhesion, morphogenesis, and mechanosensing in nonmuscle cells. However, the mechanisms by which nonmuscle myosin II (NM-II) is recruited to those structures and assembled into functional bipolar filaments have remained elusive. We report that UNC-45a is a dynamic component of actin stress fibers and functions as a myosin chaperone in vivo. UNC-45a knockout cells display severe defects in stress fiber assembly and consequent abnormalities in cell morphogenesis, polarity, and migration. Experiments combining structured-illumination microscopy, gradient centrifugation, and proteasome inhibition approaches revealed that a large fraction of NM-II and myosin-1c molecules fail to fold in the absence of UNC-45a. The remaining properly folded NM-II molecules display defects in forming functional bipolar filaments. The C-terminal UNC-45/Cro1/She4p domain of UNC-45a is critical for NM-II folding, whereas the N-terminal tetratricopeptide repeat domain contributes to the assembly of functional stress fibers. Thus, UNC-45a promotes generation of contractile actomyosin bundles through synchronized NM-II folding and filament-assembly activities.
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Affiliation(s)
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Tommi M Kotila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Giuseppe Balistreri
- Department of Biosciences, Division of General Microbiology, University of Helsinki, Helsinki, Finland
| | - Lassi Paavolainen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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29
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Yagi H, Takabayashi T, Xie MJ, Kuroda K, Sato M. Subcellular distribution of non-muscle myosin IIb is controlled by FILIP through Hsc70. PLoS One 2017; 12:e0172257. [PMID: 28234934 PMCID: PMC5325215 DOI: 10.1371/journal.pone.0172257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/02/2017] [Indexed: 12/11/2022] Open
Abstract
The neuronal spine is a small, actin-rich dendritic or somatic protrusion that serves as the postsynaptic compartment of the excitatory synapse. The morphology of the spine reflects the activity of the synapse and is regulated by the dynamics of the actin cytoskeleton inside, which is controlled by actin binding proteins such as non-muscle myosin. Previously, we demonstrated that the subcellular localization and function of myosin IIb are regulated by its binding partner, filamin-A interacting protein (FILIP). However, how the subcellular distribution of myosin IIb is controlled by FILIP is not yet known. The objective of this study was to identify potential binding partners of FILIP that contribute to its regulation of non-muscle myosin IIb. Pull-down assays detected a 70-kDa protein that was identified by mass spectrometry to be the chaperone protein Hsc70. The binding of Hsc70 to FILIP was controlled by the adenosine triphosphatase (ATPase) activity of Hsc70. Further, FILIP bound to Hsc70 via a domain that was not required for binding non-muscle myosin IIb. Inhibition of ATPase activity of Hsc70 impaired the effect of FILIP on the subcellular distribution of non-muscle myosin IIb. Further, in primary cultured neurons, an inhibitor of Hsc70 impeded the morphological change in spines induced by FILIP. Collectively, these results demonstrate that Hsc70 interacts with FILIP to mediate its effects on non-muscle myosin IIb and to regulate spine morphology.
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Affiliation(s)
- Hideshi Yagi
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, Hyogo, Japan.,Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Tetsuji Takabayashi
- Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Min-Jue Xie
- Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, University of Fukui, Fukui, Japan
| | - Kazuki Kuroda
- Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Makoto Sato
- Division of Cell Biology and Neuroscience, Department of Morphological and Physiological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, University of Fukui, Fukui, Japan.,United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, Japan.,Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
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30
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Adhikari AS, Kooiker KB, Sarkar SS, Liu C, Bernstein D, Spudich JA, Ruppel KM. Early-Onset Hypertrophic Cardiomyopathy Mutations Significantly Increase the Velocity, Force, and Actin-Activated ATPase Activity of Human β-Cardiac Myosin. Cell Rep 2016; 17:2857-2864. [PMID: 27974200 PMCID: PMC11088367 DOI: 10.1016/j.celrep.2016.11.040] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/11/2016] [Accepted: 11/11/2016] [Indexed: 01/01/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a heritable cardiovascular disorder that affects 1 in 500 people. A significant percentage of HCM is attributed to mutations in β-cardiac myosin, the motor protein that powers ventricular contraction. This study reports how two early-onset HCM mutations, D239N and H251N, affect the molecular biomechanics of human β-cardiac myosin. We observed significant increases (20%-90%) in actin gliding velocity, intrinsic force, and ATPase activity in comparison to wild-type myosin. Moreover, for H251N, we found significantly lower binding affinity between the S1 and S2 domains of myosin, suggesting that this mutation may further increase hyper-contractility by releasing active motors. Unlike previous HCM mutations studied at the molecular level using human β-cardiac myosin, early-onset HCM mutations lead to significantly larger changes in the fundamental biomechanical parameters and show clear hyper-contractility.
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Affiliation(s)
- Arjun S Adhikari
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kristina B Kooiker
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Saswata S Sarkar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chao Liu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Daniel Bernstein
- Stanford Cardiovascular Institute, 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; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305, USA.
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31
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Nag S, Sommese RF, Ujfalusi Z, Combs A, Langer S, Sutton S, Leinwand LA, Geeves MA, Ruppel KM, Spudich JA. Contractility parameters of human β-cardiac myosin with the hypertrophic cardiomyopathy mutation R403Q show loss of motor function. SCIENCE ADVANCES 2015; 1:e1500511. [PMID: 26601291 PMCID: PMC4646805 DOI: 10.1126/sciadv.1500511] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/17/2015] [Indexed: 05/20/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most frequently occurring inherited cardiovascular disease. It is caused by mutations in genes encoding the force-generating machinery of the cardiac sarcomere, including human β-cardiac myosin. We present a detailed characterization of the most debated HCM-causing mutation in human β-cardiac myosin, R403Q. Despite numerous studies, most performed with nonhuman or noncardiac myosin, there is no consensus about the mechanism of action of this mutation on the function of the enzyme. We use recombinant human β-cardiac myosin and new methodologies to characterize in vitro contractility parameters of the R403Q myosin compared to wild type. We extend our studies beyond pure actin filaments to include the interaction of myosin with regulated actin filaments containing tropomyosin and troponin. We find that, with pure actin, the intrinsic force generated by R403Q is ~15% lower than that generated by wild type. The unloaded velocity is, however, ~10% higher for R403Q myosin, resulting in a load-dependent velocity curve that has the characteristics of lower contractility at higher external loads compared to wild type. With regulated actin filaments, there is no increase in the unloaded velocity and the contractility of the R403Q myosin is lower than that of wild type at all loads. Unlike that with pure actin, the actin-activated adenosine triphosphatase activity for R403Q myosin with Ca(2+)-regulated actin filaments is ~30% lower than that for wild type, predicting a lower unloaded duty ratio of the motor. Overall, the contractility parameters studied fit with a loss of human β-cardiac myosin contractility as a result of the R403Q mutation.
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Affiliation(s)
- Suman Nag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ruth F. Sommese
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zoltan Ujfalusi
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Ariana Combs
- Department of Molecular, Cellular and Developmental Biology, BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Stephen Langer
- Department of Molecular, Cellular and Developmental Biology, BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Shirley Sutton
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology, BioFrontiers Institute, University of Colorado, Boulder, CO 80309, 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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32
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Winkelmann DA, Forgacs E, Miller MT, Stock AM. Structural basis for drug-induced allosteric changes to human β-cardiac myosin motor activity. Nat Commun 2015; 6:7974. [PMID: 26246073 PMCID: PMC4918383 DOI: 10.1038/ncomms8974] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/01/2015] [Indexed: 11/09/2022] Open
Abstract
Omecamtiv Mecarbil (OM) is a small molecule allosteric effector of cardiac myosin that is in clinical trials for treatment of systolic heart failure. A detailed kinetic analysis of cardiac myosin has shown that the drug accelerates phosphate release by shifting the equilibrium of the hydrolysis step towards products, leading to a faster transition from weak to strong actin-bound states. The structure of the human β-cardiac motor domain (cMD) with OM bound reveals a single OM-binding site nestled in a narrow cleft separating two domains of the human cMD where it interacts with the key residues that couple lever arm movement to the nucleotide state. In addition, OM induces allosteric changes in three strands of the β-sheet that provides the communication link between the actin-binding interface and the nucleotide pocket. The OM-binding interactions and allosteric changes form the structural basis for the kinetic and mechanical tuning of cardiac myosin.
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Affiliation(s)
- Donald A Winkelmann
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Eva Forgacs
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA
| | - Matthew T Miller
- Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Ann M Stock
- Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854, USA.,Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey 08854, USA
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Identification of Reproduction-Related Gene Polymorphisms Using Whole Transcriptome Sequencing in the Large White Pig Population. G3-GENES GENOMES GENETICS 2015; 5:1351-60. [PMID: 25917919 PMCID: PMC4502369 DOI: 10.1534/g3.115.018382] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent developments in high-throughput sequencing techniques have enabled large-scale analysis of genetic variations and gene expression in different tissues and species, but gene expression patterns and genetic variations in livestock are not well-characterized. In this study, we have used high-throughput transcriptomic sequencing of the Finnish Large White to identify gene expression patterns and coding polymorphisms within the breed in the testis and oviduct. The main objective of this study was to identify polymorphisms within genes that are highly and specifically expressed in male and/or female reproductive organs. The differential expression (DE) analysis underlined 1234 genes highly expressed in the testis and 1501 in the oviduct. Furthermore, we used a novel in-house R-package hoardeR for the identification of novel genes and their orthologs, which underlined 55 additional DE genes based on orthologs in the human, cow, and sheep. Identification of polymorphisms in the dataset resulted in a total of 29,973 variants, of which 10,704 were known coding variants. Fifty-seven nonsynonymous SNPs were present among genes with high expression in the testis and 67 were present in the oviduct, underlining possible influential genes for reproduction traits. Seven genes (PGR, FRAS1, TCF4, ADAT1, SPAG6, PIWIL2, and DNAH8) with polymorphisms were highlighted as reproduction-related based on their biological function. The expression and SNPs of these genes were confirmed using RT-PCR and Sanger sequencing. The identified nonsynonymous mutations within genes highly expressed in the testis or oviduct provide a list of candidate genes for reproduction traits within the pig population and enable identification of biomarkers for sow and boar fertility.
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Kanageswaran N, Demond M, Nagel M, Schreiner BSP, Baumgart S, Scholz P, Altmüller J, Becker C, Doerner JF, Conrad H, Oberland S, Wetzel CH, Neuhaus EM, Hatt H, Gisselmann G. Deep sequencing of the murine olfactory receptor neuron transcriptome. PLoS One 2015; 10:e0113170. [PMID: 25590618 PMCID: PMC4295871 DOI: 10.1371/journal.pone.0113170] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/25/2014] [Indexed: 11/18/2022] Open
Abstract
The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation.
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Affiliation(s)
| | - Marilen Demond
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- University Duisburg-Essen, Institute of Medical Radiation Biology, Essen, Germany
| | - Maximilian Nagel
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | - Sabrina Baumgart
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Paul Scholz
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | | | - Julia F. Doerner
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Heike Conrad
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- Cluster of Excellence and DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Sonja Oberland
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian H. Wetzel
- University of Regensburg, Department of Psychiatry and Psychotherapy, Molecular Neurosciences, Regensburg, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hanns Hatt
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Günter Gisselmann
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
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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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Thermally-induced structural changes in an armadillo repeat protein suggest a novel thermosensor mechanism in a molecular chaperone. FEBS Lett 2014; 589:123-30. [PMID: 25436418 DOI: 10.1016/j.febslet.2014.11.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 01/12/2023]
Abstract
Molecular chaperones are commonly identified by their ability to suppress heat-induced protein aggregation. The muscle-specific molecular chaperone UNC-45B is known to be involved in myosin folding and is trafficked to the sarcomeres A-band during thermal stress. Here, we identify temperature-dependent structural changes in the UCS chaperone domain of UNC-45B that occur within a physiologically relevant heat-shock range. We show that distinct changes to the armadillo repeat protein topology result in exposure of hydrophobic patches, and increased flexibility of the molecule. These rearrangements suggest the existence of a novel thermosensor within the chaperone domain of UNC-45B. We propose that these changes may function to suppress aggregation under stress by allowing binding to a wide variety of aggregation prone loops on its client.
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Spudich JA. Hypertrophic and dilated cardiomyopathy: four decades of basic research on muscle lead to potential therapeutic approaches to these devastating genetic diseases. Biophys J 2014; 106:1236-49. [PMID: 24655499 PMCID: PMC3985504 DOI: 10.1016/j.bpj.2014.02.011] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/30/2014] [Accepted: 02/04/2014] [Indexed: 01/10/2023] Open
Abstract
With the advent of technologies to obtain the complete sequence of the human genome in a cost-effective manner, this decade and those to come will see an exponential increase in our understanding of the underlying genetics that lead to human disease. And where we have a deep understanding of the biochemical and biophysical basis of the machineries and pathways involved in those genetic changes, there are great hopes for the development of modern therapeutics that specifically target the actual machinery and pathways altered by individual mutations. Prime examples of such a genetic disease are those classes of hypertrophic and dilated cardiomyopathy that result from single amino-acid substitutions in one of several of the proteins that make up the cardiac sarcomere or from the truncation of myosin binding protein C. Hypertrophic cardiomyopathy alone affects ∼1 in 500 individuals, and it is the leading cause of sudden cardiac death in young adults. Here I describe approaches to understand the molecular basis of the alterations in power output that result from these mutations. Small molecules binding to the mutant sarcomeric protein complex should be able to mitigate the effects of hypertrophic and dilated cardiomyopathy mutations at their sources, leading to possible new therapeutic approaches for these genetic diseases.
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Affiliation(s)
- James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California.
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Jilani Y, Lu S, Lei H, Karnitz LM, Chadli A. UNC45A localizes to centrosomes and regulates cancer cell proliferation through ChK1 activation. Cancer Lett 2014; 357:114-120. [PMID: 25444911 DOI: 10.1016/j.canlet.2014.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 11/26/2022]
Abstract
The UCS family of proteins regulates cellular functions through their interactions with myosin. Here we show that one member of this family, UNC45A, is also a novel centrosomal protein. UNC45A is required for cellular proliferation of cancer cell in vitro and for tumor growth in vivo through its ability to bind and regulate ChK1 nuclear-cytoplasmic localization in an Hsp90-independent manner. Immunocytochemical and biochemical fractionation studies revealed that UNC45A and ChK1 co-localize to the centrosome. Inhibition of UNC45A expression reduced ChK1 activation and its tethering to the centrosome, events required for proper centrosome function. Lack of UNC45A caused the accumulation of multi-nucleated cells, consistent with a defect in Chk1 regulation of centrosomes. These findings identify a novel centrosomal function for UNC45A and its role in cell proliferation and tumorigenesis.
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Affiliation(s)
- Yasmeen Jilani
- Molecular Oncology and Biomarkers Program, GRU Cancer Center, Georgia Regents University, 1410 Laney Walker Blvd, CN-3151, Augusta, GA 30912, USA
| | - Su Lu
- Molecular Oncology and Biomarkers Program, GRU Cancer Center, Georgia Regents University, 1410 Laney Walker Blvd, CN-3151, Augusta, GA 30912, USA
| | - Huang Lei
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912
| | - Larry M Karnitz
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Ahmed Chadli
- Molecular Oncology and Biomarkers Program, GRU Cancer Center, Georgia Regents University, 1410 Laney Walker Blvd, CN-3151, Augusta, GA 30912, USA.
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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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40
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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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41
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Chaperone-enhanced purification of unconventional myosin 15, a molecular motor specialized for stereocilia protein trafficking. Proc Natl Acad Sci U S A 2014; 111:12390-5. [PMID: 25114250 DOI: 10.1073/pnas.1409459111] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unconventional myosin 15 is a molecular motor expressed in inner ear hair cells that transports protein cargos within developing mechanosensory stereocilia. Mutations of myosin 15 cause profound hearing loss in humans and mice; however, the properties of this motor and its regulation within the stereocilia organelle are unknown. To address these questions, we expressed a subfragment 1-like (S1) truncation of mouse myosin 15, comprising the predicted motor domain plus three light-chain binding sites. Following unsuccessful attempts to express functional myosin 15-S1 using the Spodoptera frugiperda (Sf9)-baculovirus system, we discovered that coexpression of the muscle-myosin-specific chaperone UNC45B, in addition to the chaperone heat-shock protein 90 (HSP90) significantly increased the yield of functional protein. Surprisingly, myosin 15-S1 did not bind calmodulin with high affinity. Instead, the IQ domains bound essential and regulatory light chains that are normally associated with class II myosins. We show that myosin 15-S1 is a barbed-end-directed motor that moves actin filaments in a gliding assay (∼ 430 nm · s(-1) at 30 °C), using a power stroke of 7.9 nm. The maximum ATPase rate (k(cat) ∼ 6 s(-1)) was similar to the actin-detachment rate (k(det) = 6.2 s(-1)) determined in single molecule optical trapping experiments, indicating that myosin 15-S1 was rate limited by transit through strongly actin-bound states, similar to other processive myosin motors. Our data further indicate that in addition to folding muscle myosin, UNC45B facilitates maturation of an unconventional myosin. We speculate that chaperone coexpression may be a simple method to optimize the purification of other myosin motors from Sf9 insect cells.
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42
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Myhre JL, Hills JA, Jean F, Pilgrim DB. Unc45b is essential for early myofibrillogenesis and costamere formation in zebrafish. Dev Biol 2014; 390:26-40. [DOI: 10.1016/j.ydbio.2014.02.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/25/2014] [Indexed: 01/16/2023]
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43
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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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44
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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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45
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Stark BC, James ML, Pollard LW, Sirotkin V, Lord M. UCS protein Rng3p is essential for myosin-II motor activity during cytokinesis in fission yeast. PLoS One 2013; 8:e79593. [PMID: 24244528 PMCID: PMC3828377 DOI: 10.1371/journal.pone.0079593] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/27/2013] [Indexed: 12/25/2022] Open
Abstract
UCS proteins have been proposed to operate as co-chaperones that work with Hsp90 in the de novo folding of myosin motors. The fission yeast UCS protein Rng3p is essential for actomyosin ring assembly and cytokinesis. Here we investigated the role of Rng3p in fission yeast myosin-II (Myo2p) motor activity. Myo2p isolated from an arrested rng3-65 mutant was capable of binding actin, yet lacked stability and activity based on its expression levels and inactivity in ATPase and actin filament gliding assays. Myo2p isolated from a myo2-E1 mutant (a mutant hyper-sensitive to perturbation of Rng3p function) showed similar behavior in the same assays and exhibited an altered motor conformation based on limited proteolysis experiments. We propose that Rng3p is not required for the folding of motors per se, but instead works to ensure the activity of intrinsically unstable myosin-II motors. Rng3p is specific to conventional myosin-II and the actomyosin ring, and is not required for unconventional myosin motor function at other actin structures. However, artificial destabilization of myosin-I motors at endocytic actin patches (using a myo1-E1 mutant) led to recruitment of Rng3p to patches. Thus, while Rng3p is specific to myosin-II, UCS proteins are adaptable and can respond to changes in the stability of other myosin motors.
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Affiliation(s)
- Benjamin C. Stark
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, United States of America
| | - Michael L. James
- Department of Cell and Developmental Biology, State University of New York - Upstate Medical University, Syracuse, New York, United States of America
| | - Luther W. Pollard
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, United States of America
| | - Vladimir Sirotkin
- Department of Cell and Developmental Biology, State University of New York - Upstate Medical University, Syracuse, New York, United States of America
| | - Matthew Lord
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
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Sequence and domain conservation of the coelacanth Hsp40 and Hsp90 chaperones suggests conservation of function. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 322:359-78. [DOI: 10.1002/jez.b.22541] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 07/13/2013] [Accepted: 08/16/2013] [Indexed: 01/17/2023]
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Expression of heat shock protein (Hsp90) paralogues is regulated by amino acids in skeletal muscle of Atlantic salmon. PLoS One 2013; 8:e74295. [PMID: 24040223 PMCID: PMC3765391 DOI: 10.1371/journal.pone.0074295] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 07/29/2013] [Indexed: 01/09/2023] Open
Abstract
Heat shock proteins 90 (Hsp90) have an essential role in sarcomere formation and differentiation in skeletal muscle and also act as molecular chaperones during protein folding impacting a wide range of physiological processes. We characterised and provided a phylogenetically consistent nomenclature for the complete repertoire of six Hsp90 paralogues present in duplicated salmonid fish genomes (Hsp90α1a, Hsp90α1b, Hsp90α2a, Hsp90α2b, Hsp90ß1a and Hsp90ß1b). The expression of paralogues in fast skeletal muscle was investigated using in vivo fasting-feeding experiments and primary myogenic cultures. Fasted juvenile Atlantic salmon (Salmo salar) showed a transient 2 to 8-fold increase in the expression of all 4 Hsp90α paralogues within 24h of satiation feeding. Hsp90α1a and hsp90α1b also showed a pronounced secondary increase in expression after 10 days, concomitant with muscle differentiation and the expression of myogenin and sarcomeric proteins (mlc2, myhc). Hsp90ß1b was constitutively expressed whereas Hsp90ß1a expression was downregulated 10-fold between fasted and fed individuals. Hsp90α1a and Hsp90α1b were upregulated 10 to 15-fold concomitant with myotube formation and muscle differentiation in vitro whereas other Hsp90 paralogues showed no change in expression. In cells starved of amino acid (AA) and serum for 72h the addition of AA, but not insulin-like growth factor 1, increased phosphorylation of mTor and expression of all 4 hsp90α paralogues and associated co-chaperones including hsp30, tbcb, pdia4, pdia6, stga and fk504bp1, indicating a general activation of the protein folding response. In contrast, Hsp90ß1a expression in vitro was unresponsive to AA treatment indicating that some other as yet uncharacterised signal(s) regulate its expression in response to altered nutritional state.
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48
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Chaperone-interacting TPR proteins in Caenorhabditis elegans. J Mol Biol 2013; 425:2922-39. [PMID: 23727266 DOI: 10.1016/j.jmb.2013.05.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 04/30/2013] [Accepted: 05/22/2013] [Indexed: 11/21/2022]
Abstract
The ATP-hydrolyzing molecular chaperones Hsc70/Hsp70 and Hsp90 bind a diverse set of tetratricopeptide repeat (TPR)-containing cofactors via their C-terminal peptide motifs IEEVD and MEEVD. These cochaperones contribute to substrate turnover and confer specific activities to the chaperones. Higher eukaryotic genomes encode a large number of TPR-domain-containing proteins. The human proteome contains more than 200 TPR proteins, and that of Caenorhabditis elegans, about 80. It is unknown how many of them interact with Hsc70 or Hsp90. We systematically screened the C. elegans proteome for TPR-domain-containing proteins that likely interact with Hsc70 and Hsp90 and ranked them due to their similarity with known chaperone-interacting TPRs. We find C. elegans to encode many TPR proteins, which are not present in yeast. All of these have homologs in fruit fly or humans. Highly ranking uncharacterized open reading frames C33H5.8, C34B2.5 and ZK370.8 may encode weakly conserved homologs of the human proteins RPAP3, TTC1 and TOM70. C34B2.5 and ZK370.8 bind both Hsc70 and Hsp90 with low micromolar affinities. Mutation of amino acids involved in EEVD binding disrupts the interaction. In vivo, ZK370.8 is localized to mitochondria in tissues with known chaperone requirements, while C34B2.5 colocalizes with Hsc70 in intestinal cells. The highest-ranking open reading frame with non-conserved EEVD-interacting residues, F52H3.5, did not show any binding to Hsc70 or Hsp90, suggesting that only about 15 of the TPR-domain-containing proteins in C. elegans interact with chaperones, while the many others may have evolved to bind other ligands.
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The chaperone Hsp90: changing partners for demanding clients. Trends Biochem Sci 2013; 38:253-62. [PMID: 23507089 DOI: 10.1016/j.tibs.2013.02.003] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 01/25/2013] [Accepted: 02/04/2013] [Indexed: 11/21/2022]
Abstract
The heat shock protein (Hsp)90 chaperone machinery regulates the activity of hundreds of client proteins in the eukaryotic cytosol. It undergoes large conformational changes between states that are similar in energy. These transitions are rate-limiting for the ATPase cycle. It has become evident that several of the many Hsp90 co-chaperones affect the conformational equilibrium by stabilizing specific intermediate states. Consequently, there is an ordered progression of different co-chaperones during the conformational cycle. Asymmetric complexes containing two different co-chaperones may be important for the processing of the client protein, although our understanding of this aspect, as well as the details of the interaction of Hsp90 with client proteins, is still in its infancy.
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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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