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Shultz KD, Al Anbari YF, Wright NT. I told you to stop: obscurin's role in epithelial cell migration. Biochem Soc Trans 2024:BST20240564. [PMID: 39051125 DOI: 10.1042/bst20240564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/02/2024] [Accepted: 07/11/2024] [Indexed: 07/27/2024]
Abstract
The giant cytoskeletal protein obscurin contains multiple cell signaling domains that influence cell migration. Here, we follow each of these pathways, examine how these pathways modulate epithelial cell migration, and discuss the cross-talk between these pathways. Specifically, obscurin uses its PH domain to inhibit phosphoinositide-3-kinase (PI3K)-dependent migration and its RhoGEF domain to activate RhoA and slow cell migration. While obscurin's effect on the PI3K pathway agrees with the literature, obscurin's effect on the RhoA pathway runs counter to most other RhoA effectors, whose activation tends to lead to enhanced motility. Obscurin also phosphorylates cadherins, and this may also influence cell motility. When taken together, obscurin's ability to modulate three independent cell migration pathways is likely why obscurin knockout cells experience enhanced epithelial to mesenchymal transition, and why obscurin is a frequently mutated gene in several types of cancer.
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Affiliation(s)
- Kamrin D Shultz
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, U.S.A
| | - Yasmin F Al Anbari
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, U.S.A
| | - Nathan T Wright
- Department of Chemistry and Biochemistry, James Madison University, 901 Carrier Dr., Harrisonburg, VA 22807, U.S.A
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2
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Ouderkirk S, Sedley A, Ong M, Shifflet MR, Harkrider QC, Wright NT, Miller CJ. A Perspective on Developing Modeling and Image Analysis Tools to Investigate Mechanosensing Proteins. Integr Comp Biol 2023; 63:1532-1542. [PMID: 37558388 PMCID: PMC10755202 DOI: 10.1093/icb/icad107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 08/11/2023] Open
Abstract
The shift of funding organizations to prioritize interdisciplinary work points to the need for workflow models that better accommodate interdisciplinary studies. Most scientists are trained in a specific field and are often unaware of the kind of insights that other disciplines could contribute to solving various problems. In this paper, we present a perspective on how we developed an experimental pipeline between a microscopy and image analysis/bioengineering lab. Specifically, we connected microscopy observations about a putative mechanosensing protein, obscurin, to image analysis techniques that quantify cell changes. While the individual methods used are well established (fluorescence microscopy; ImageJ WEKA and mTrack2 programs; MATLAB), there are no existing best practices for how to integrate these techniques into a cohesive, interdisciplinary narrative. Here, we describe a broadly applicable workflow of how microscopists can more easily quantify cell properties (e.g., perimeter, velocity) from microscopy videos of eukaryotic (MDCK) adherent cells. Additionally, we give examples of how these foundational measurements can create more complex, customizable cell mechanics tools and models.
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Affiliation(s)
- Stephanie Ouderkirk
- Department of Chemistry, James Madison University, Harrisonburg, VA 22807, USA
| | - Alex Sedley
- Department of Engineering, James Madison University, Harrisonburg, VA 22807, USA
| | - Mason Ong
- Department of Engineering, James Madison University, Harrisonburg, VA 22807, USA
| | - Mary Ruth Shifflet
- Department of Chemistry, Bridgewater College, Bridgewater, VA 22812, USA
| | - Quinn C Harkrider
- Department of Chemistry, James Madison University, Harrisonburg, VA 22807, USA
| | - Nathan T Wright
- Department of Chemistry, James Madison University, Harrisonburg, VA 22807, USA
| | - Callie J Miller
- Department of Engineering, James Madison University, Harrisonburg, VA 22807, USA
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3
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Koch D, Kho AL, Fukuzawa A, Alexandrovich A, Vanaanen KJ, Beavil A, Pfuhl M, Rees M, Gautel M. Obscurin Rho GEF domains are phosphorylated by MST-family kinases but do not exhibit nucleotide exchange factor activity towards Rho GTPases in vitro. PLoS One 2023; 18:e0284453. [PMID: 37079638 PMCID: PMC10118190 DOI: 10.1371/journal.pone.0284453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 04/01/2023] [Indexed: 04/21/2023] Open
Abstract
Obscurin is a giant muscle protein (>800 kDa) featuring multiple signalling domains, including an SH3-DH-PH domain triplet from the Trio-subfamily of guanosine nucleotide exchange factors (GEFs). While previous research suggests that these domains can activate the small GTPases RhoA and RhoQ in cells, in vitro characterization of these interactions using biophysical techniques has been hampered by the intrinsic instability of obscurin GEF domains. To study substrate specificity, mechanism and regulation of obscurin GEF function by individual domains, we successfully optimized recombinant production of obscurin GEF domains and found that MST-family kinases phosphorylate the obscurin DH domain at Thr5798. Despite extensive testing of multiple GEF domain fragments, we did not detect any nucleotide exchange activity in vitro against 9 representative small GTPases. Bioinformatic analyses show that obscurin differs from other Trio-subfamily GEFs in several important aspects. While further research is necessary to evaluate obscurin GEF activity in vivo, our results indicate that obscurin has atypical GEF domains that, if catalytically active at all, are subject to complex regulation.
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Affiliation(s)
- Daniel Koch
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Ay Lin Kho
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Atsushi Fukuzawa
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Alexander Alexandrovich
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Kutti J. Vanaanen
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Andrew Beavil
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Mark Pfuhl
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Martin Rees
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
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4
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Is the fundamental pathology in Duchenne's muscular dystrophy caused by a failure of glycogenolysis–glycolysis in costameres? J Genet 2023. [DOI: 10.1007/s12041-022-01410-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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5
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McCourt JL, Stearns-Reider KM, Mamsa H, Kannan P, Afsharinia MH, Shu C, Gibbs EM, Shin KM, Kurmangaliyev YZ, Schmitt LR, Hansen KC, Crosbie RH. Multi-omics analysis of sarcospan overexpression in mdx skeletal muscle reveals compensatory remodeling of cytoskeleton-matrix interactions that promote mechanotransduction pathways. Skelet Muscle 2023; 13:1. [PMID: 36609344 PMCID: PMC9817407 DOI: 10.1186/s13395-022-00311-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 12/06/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The dystrophin-glycoprotein complex (DGC) is a critical adhesion complex of the muscle cell membrane, providing a mechanical link between the extracellular matrix (ECM) and the cortical cytoskeleton that stabilizes the sarcolemma during repeated muscle contractions. One integral component of the DGC is the transmembrane protein, sarcospan (SSPN). Overexpression of SSPN in the skeletal muscle of mdx mice (murine model of DMD) restores muscle fiber attachment to the ECM in part through an associated increase in utrophin and integrin adhesion complexes at the cell membrane, protecting the muscle from contraction-induced injury. In this study, we utilized transcriptomic and ECM protein-optimized proteomics data sets from wild-type, mdx, and mdx transgenic (mdxTG) skeletal muscle tissues to identify pathways and proteins driving the compensatory action of SSPN overexpression. METHODS The tibialis anterior and quadriceps muscles were isolated from wild-type, mdx, and mdxTG mice and subjected to bulk RNA-Seq and global proteomics analysis using methods to enhance capture of ECM proteins. Data sets were further analyzed through the ingenuity pathway analysis (QIAGEN) and integrative gene set enrichment to identify candidate networks, signaling pathways, and upstream regulators. RESULTS Through our multi-omics approach, we identified 3 classes of differentially expressed genes and proteins in mdxTG muscle, including those that were (1) unrestored (significantly different from wild type, but not from mdx), (2) restored (significantly different from mdx, but not from wild type), and (3) compensatory (significantly different from both wild type and mdx). We identified signaling pathways that may contribute to the rescue phenotype, most notably cytoskeleton and ECM organization pathways. ECM-optimized proteomics revealed an increased abundance of collagens II, V, and XI, along with β-spectrin in mdxTG samples. Using ingenuity pathway analysis, we identified upstream regulators that are computationally predicted to drive compensatory changes, revealing a possible mechanism of SSPN rescue through a rewiring of cell-ECM bidirectional communication. We found that SSPN overexpression results in upregulation of key signaling molecules associated with regulation of cytoskeleton organization and mechanotransduction, including Yap1, Sox9, Rho, RAC, and Wnt. CONCLUSIONS Our findings indicate that SSPN overexpression rescues dystrophin deficiency partially through mechanotransduction signaling cascades mediated through components of the ECM and the cortical cytoskeleton.
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Affiliation(s)
- Jackie L. McCourt
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Kristen M. Stearns-Reider
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Orthopedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Hafsa Mamsa
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Pranav Kannan
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Mohammad Hossein Afsharinia
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Cynthia Shu
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Elizabeth M. Gibbs
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Kara M. Shin
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Yerbol Z. Kurmangaliyev
- grid.19006.3e0000 0000 9632 6718Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Lauren R. Schmitt
- grid.241116.10000000107903411Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, CO USA
| | - Kirk C. Hansen
- grid.241116.10000000107903411Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, CO USA
| | - Rachelle H. Crosbie
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Molecular Biology Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Broad Stem Cell Research Center, University of California, Los Angeles, CA USA
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6
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A current overview of RhoA, RhoB, and RhoC functions in vascular biology and pathology. Biochem Pharmacol 2022; 206:115321. [DOI: 10.1016/j.bcp.2022.115321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
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7
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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8
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Tuntithavornwat S, Shea DJ, Wong BS, Guardia T, Lee SJ, Yankaskas CL, Zheng L, Kontrogianni-Konstantopoulos A, Konstantopoulos K. Giant obscurin regulates migration and metastasis via RhoA-dependent cytoskeletal remodeling in pancreatic cancer. Cancer Lett 2022; 526:155-167. [PMID: 34826548 PMCID: PMC9427004 DOI: 10.1016/j.canlet.2021.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/15/2021] [Accepted: 11/12/2021] [Indexed: 12/23/2022]
Abstract
Obscurins, encoded by the OBSCN gene, are giant cytoskeletal proteins with structural and regulatory roles. Large scale omics analyses reveal that OBSCN is highly mutated across different types of cancer, exhibiting a 5-8% mutation frequency in pancreatic cancer. Yet, the functional role of OBSCN in pancreatic cancer progression and metastasis has to be delineated. We herein show that giant obscurins are highly expressed in normal pancreatic tissues, but their levels are markedly reduced in pancreatic ductal adenocarcinomas. Silencing of giant obscurins in non-tumorigenic Human Pancreatic Ductal Epithelial (HPDE) cells and obscurin-expressing Panc5.04 pancreatic cancer cells induces an elongated, spindle-like morphology and faster cell migration via cytoskeletal remodeling. Specifically, depletion of giant obscurins downregulates RhoA activity, which in turn results in reduced focal adhesion density, increased microtubule growth rate and faster actin dynamics. Although OBSCN knockdown is not sufficient to induce de novo tumorigenesis, it potentiates tumor growth in a subcutaneous implantation model and exacerbates metastasis in a hemispleen murine model of pancreatic cancer metastasis, thereby shortening survival. Collectively, these findings reveal a critical role of giant obscurins as tumor suppressors in normal pancreatic epithelium whose loss of function induces RhoA-dependent cytoskeletal remodeling, and promotes cell migration, tumor growth and metastasis.
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Affiliation(s)
- Soontorn Tuntithavornwat
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Daniel J Shea
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Bin Sheng Wong
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA; Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, USA
| | - Talia Guardia
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Se Jong Lee
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Christopher L Yankaskas
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA; Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, USA
| | - Lei Zheng
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aikaterini Kontrogianni-Konstantopoulos
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.
| | - Konstantinos Konstantopoulos
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA; Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, USA; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD, USA.
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9
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Rodríguez-Fdez S, Bustelo XR. Rho GTPases in Skeletal Muscle Development and Homeostasis. Cells 2021; 10:cells10112984. [PMID: 34831205 PMCID: PMC8616218 DOI: 10.3390/cells10112984] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
Rho guanosine triphosphate hydrolases (GTPases) are molecular switches that cycle between an inactive guanosine diphosphate (GDP)-bound and an active guanosine triphosphate (GTP)-bound state during signal transduction. As such, they regulate a wide range of both cellular and physiological processes. In this review, we will summarize recent work on the role of Rho GTPase-regulated pathways in skeletal muscle development, regeneration, tissue mass homeostatic balance, and metabolism. In addition, we will present current evidence that links the dysregulation of these GTPases with diseases caused by skeletal muscle dysfunction. Overall, this information underscores the critical role of a number of members of the Rho GTPase subfamily in muscle development and the overall metabolic balance of mammalian species.
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Affiliation(s)
- Sonia Rodríguez-Fdez
- Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain;
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
- Wellcome-MRC Institute of Metabolic Science and MRC Metabolic Diseases Unit, University of Cambridge, Cambridge CB2 0QQ, UK
- Correspondence: or
| | - Xosé R. Bustelo
- Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain;
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
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10
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Wu G, Liu J, Liu M, Huang Q, Ruan J, Zhang C, Wang D, Sun X, Jiang W, Kang L, Wang J, Song L. Truncating Variants in OBSCN Gene Associated With Disease-Onset and Outcomes of Hypertrophic Cardiomyopathy. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2021; 14:e003401. [PMID: 34601892 DOI: 10.1161/circgen.121.003401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The presence of variants in OBSCN was identified to be linked to hypertrophic cardiomyopathy (HCM), but whether OBSCN truncating variants were associated with HCM remained unknown. METHODS Whole-exome sequencing was performed in 986 patients with HCM and 761 non-HCM controls to search for OBSCN truncating variants, and the result was tested in a replication cohort consisting of 529 patients with HCM and 307 controls. The association of the OBSCN truncating variants with baseline characteristics and prognosis of patients with HCM were ascertained. RESULTS There were 28 qualifying truncating variants in the OBSCN gene detected in 26 (2.6%) patients with HCM and 6 (0.8%) controls. The OBSCN truncating variants were more prevalent in patients with HCM than controls (odds ratio, 3.4, P=0.004). This association was confirmed in the replication cohort (odds ratio, 3.8, P=0.024). The combined effects of the two cohorts estimated the odds ratio to be 3.58 (P<0.001). Patients with or without OBSCN truncating variants shared similar demographic and echocardiographic variables at baseline. During 3.3±2.4 years (4795 patient-years) follow-up, the patients with OBSCN truncating variants were more likely to experience cardiovascular death (adjusted hazard ratio, 3.1 [95% CI, 1.40-6.70], P=0.005) and all-cause death (adjusted hazard ratio, 2.63 [95% CI, 1.21-5.71], P=0.015). CONCLUSIONS Our data indicated that OBSCN truncating variants contributed to the disease-onset of HCM, and increased the risk of malignant events in patients with HCM.
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Affiliation(s)
- Guixin Wu
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jie Liu
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Minghao Liu
- Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qiya Huang
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jieyun Ruan
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Channa Zhang
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dong Wang
- Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaolu Sun
- Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen Jiang
- Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lianming Kang
- Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jizheng Wang
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Song
- State Key Laboratory of Cardiovascular Disease (G.W., J.L., Q.H., J.R., C.Z., J.W., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Cardiomyopathy Ward (G.W., J.L., M.L., Q.H., J.R., D.W., X.S., W.J., L.K., L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,National Clinical Research Center of Cardiovascular Diseases (L.S.), Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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11
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Guardia T, Eason M, Kontrogianni-Konstantopoulos A. Obscurin: A multitasking giant in the fight against cancer. Biochim Biophys Acta Rev Cancer 2021; 1876:188567. [PMID: 34015411 PMCID: PMC8349851 DOI: 10.1016/j.bbcan.2021.188567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/03/2021] [Accepted: 05/11/2021] [Indexed: 12/19/2022]
Abstract
Giant obscurins (720-870 kDa), encoded by OBSCN, were originally discovered in striated muscles as cytoskeletal proteins with scaffolding and regulatory roles. Recently though, they have risen to the spotlight as key players in cancer development and progression. Herein, we provide a timely prudent synopsis of the expanse of OBSCN mutations across 16 cancer types. Given the extensive work on OBSCN's role in breast epithelium, we summarize functional studies implicating obscurins as potent tumor suppressors in breast cancer and delve into an in silico analysis of its mutational profile and epigenetic (de)regulation using different dataset platforms and sophisticated computational tools. Lastly, we formally describe the OBSCN-Antisense-RNA-1 gene, which belongs to the long non-coding RNA family and discuss its potential role in modulating OBSCN expression in breast cancer. Collectively, we highlight the escalating involvement of obscurins in cancer biology and outline novel potential mechanisms of OBSCN (de)regulation that warrant further investigation.
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Affiliation(s)
- Talia Guardia
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Matthew Eason
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Aikaterini Kontrogianni-Konstantopoulos
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, USA.
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12
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Jin F, Guo Y, Wang Z, Badughaish A, Pan X, Zhang L, Qi F. The pathophysiological nature of sarcomeres in trigger points in patients with myofascial pain syndrome: A preliminary study. Eur J Pain 2020; 24:1968-1978. [PMID: 32841448 PMCID: PMC7693045 DOI: 10.1002/ejp.1647] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/08/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022]
Abstract
Background Myofascial pain syndrome (MPS) has a high global prevalence and is associated with myofascial trigger points (MTrPs) in taut bands or nodules. Little is known about the aetiology. The current study assessed the pathophysiological characteristics of MTrPs in MPS patients. Methods Biopsies of the trapezius muscle were collected from the MTrPs of MPS patients (MTrP group; n = 29) and from healthy controls (control group; n = 24), and their morphologies were analysed via haematoxylin‐eosin (H&E) and Masson staining. A protein microarray was used to detect the receptor tyrosine kinase (RTK) family proteins. mRNA and long non‐coding RNA (lncRNA) sequencing and analysis were conducted, and immunohistochemistry and Western blotting were used to examine the expression of EphB and Rho family proteins. Results Abnormally contracted sarcomeres showed enlarged, round fibres without inflammation or fibrosis. An lncRNA‐mRNA network analysis revealed activation of muscle contraction signalling pathways in MTrP regions. Among RTK family proteins, 15 exhibited increased phosphorylation, and two exhibited decreased phosphorylation in the MTrP regions relative to control levels. In particular, EphB1/EphB2 phosphorylation was increased on the muscle cell membranes of abnormal sarcomeres. RhoA and Rac1, but not cell division control protein 42 (Cdc42), were activated in the abnormal sarcomeres. Conclusions EphB1/EphB2 and RhoA/Rac1 might play roles in the aetiology of abnormally contracted sarcomeres in MTrPs without inflammatory cell infiltration and fibrotic adhesion. Significance Contracted sarcomeres were found in MTrP regions, which is consistent with the MTrP formation hypothesis. EphB1/EphB2 and RhoA/Rac1 might play roles in the sarcomere contractile sites of MTrPs, which may be promising therapeutic targets.
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Affiliation(s)
- Feihong Jin
- Department of Anesthesiology and Pain Clinic, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China
| | - Yaqiu Guo
- Department of Anesthesiology and Pain Clinic, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China.,Department of Anesthesiology, Jinan Maternity and Child Care Hospital, Ji'nan, China
| | - Zi Wang
- Department of Anesthesiology and Pain Clinic, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China.,Department of Anesthesiology, First Affiliated Hospital of Shandong TCM University, Ji'nan, China
| | - Ahmed Badughaish
- Department of Anesthesiology and Pain Clinic, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China
| | - Xin Pan
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China
| | - Li Zhang
- Department of Orthopedics, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China
| | - Feng Qi
- Department of Anesthesiology and Pain Clinic, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Ji'nan, China
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13
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Hu LYR, Kontrogianni-Konstantopoulos A. Proteomic Analysis of Myocardia Containing the Obscurin R4344Q Mutation Linked to Hypertrophic Cardiomyopathy. Front Physiol 2020; 11:478. [PMID: 32528308 PMCID: PMC7247546 DOI: 10.3389/fphys.2020.00478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 12/25/2022] Open
Abstract
Obscurin is a giant cytoskeletal protein with structural and regulatory roles encoded by the OBSCN gene. Recently, mutations in OBSCN were associated with the development of different forms of cardiomyopathies, including hypertrophic cardiomyopathy (HCM). We previously reported that homozygous mice carrying the HCM-linked R4344Q obscurin mutation develop arrhythmia by 1-year of age under sedentary conditions characterized by increased heart rate, frequent incidents of premature ventricular contractions, and episodes of spontaneous ventricular tachycardia. In an effort to delineate the molecular mechanisms that contribute to the observed arrhythmic phenotype, we subjected protein lysates prepared from left ventricles of 1-year old R4344Q and wild-type mice to comparative proteomics analysis using tandem mass spectrometry; raw data are available via ProteomeXchange with identifier PXD017314. We found that the expression levels of proteins involved in cardiac function and disease, cytoskeletal organization, electropotential regulation, molecular transport and metabolism were significantly altered. Moreover, phospho-proteomic evaluation revealed changes in the phosphorylation profile of Ca2+ cycling proteins, including sAnk1.5, a major binding partner of obscurin localized in the sarcoplasmic reticulum; notably, this is the first report indicating that sAnk1 undergoes phosphorylation. Taken together, our findings implicate obscurin in diverse cellular processes within the myocardium, which is consistent with its multiple binding partners, localization in different subcellular compartments, and disease association.
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Affiliation(s)
- Li-Yen R Hu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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14
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Humphries BA, Wang Z, Yang C. MicroRNA Regulation of the Small Rho GTPase Regulators-Complexities and Opportunities in Targeting Cancer Metastasis. Cancers (Basel) 2020; 12:E1092. [PMID: 32353968 PMCID: PMC7281527 DOI: 10.3390/cancers12051092] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 02/07/2023] Open
Abstract
The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.
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Affiliation(s)
- Brock A. Humphries
- Center for Molecular Imaging, Department of Radiology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Zhishan Wang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
| | - Chengfeng Yang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
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15
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Bukosza EN, Kratochwill K, Kornauth C, Schachner H, Aufricht C, Gebeshuber CA. Podocyte RNA sequencing reveals Wnt- and ECM-associated genes as central in FSGS. PLoS One 2020; 15:e0231898. [PMID: 32302353 PMCID: PMC7164636 DOI: 10.1371/journal.pone.0231898] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 04/02/2020] [Indexed: 12/18/2022] Open
Abstract
Loss of podocyte differentiation can cause nephrotic-range proteinuria and Focal and Segmental Glomerulosclerosis (FSGS). As specific therapy is still lacking, FSGS frequently progresses to end-stage renal disease. The exact molecular mechanisms of FSGS and gene expression changes in podocytes are complex and widely unknown as marker changes have mostly been assessed on the glomerular level. To gain a better insight, we isolated podocytes of miR-193a overexpressing mice, which suffer from FSGS due to suppression of the podocyte master regulator Wt1. We characterised the podocytic gene expression changes by RNAseq and identified many novel candidate genes not linked to FSGS so far. This included strong upregulation of the receptor tyrosine kinase EphA6 and a massive dysregulation of circadian genes including the loss of the transcriptional activator Arntl. By comparison with podocyte-specific changes in other FSGS models we found a shared dysregulation of genes associated with the Wnt signaling cascade, while classical podocyte-specific genes appeared widely unaltered. An overlap with gene expression screens from human FSGS patients revealed a strong enrichment in genes associated with extra-cellular matrix (ECM) and metabolism. Our data suggest that FSGS progression might frequently depend on pathways that are often overlooked when considering podocyte homeostasis.
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Affiliation(s)
- Eva Nora Bukosza
- Translational Medicine Institute, Semmelweis University Budapest, Budapest, Hungary
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Klaus Kratochwill
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Molecular Stress Research in Peritoneal Dialysis, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Christoph Kornauth
- Clinical Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Helga Schachner
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Christoph Aufricht
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Christoph A. Gebeshuber
- Division of Pediatric Nephrology and Gastroenterology, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
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16
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Association of 3p27.1 Variants with Whole Body Lean Mass Identified by a Genome-wide Association Study. Sci Rep 2020; 10:4293. [PMID: 32152362 PMCID: PMC7062907 DOI: 10.1038/s41598-020-61272-z] [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: 10/07/2019] [Accepted: 02/25/2020] [Indexed: 12/25/2022] Open
Abstract
Whole body lean mass (WBLM) is a heritable trait predicting sarcopenia. To identify genomic locus underlying WBLM, we performed a genome-wide association study of fat-adjusted WBLM in the Framingham Heart Study (FHS, N = 6,004), and replicated in the Kansas City Osteoporosis Study (KCOS, N = 2,207). We identified a novel locus 3p27.1 that was associated with WBLM (lead SNP rs3732593 P = 7.19 × 10-8) in the discovery FHS sample, and the lead SNP was successfully replicated in the KCOS sample (one-sided P = 0.04). Bioinformatics analysis found that this SNP and its adjacent SNPs had the function of regulating enhancer activity in skeletal muscle myoblasts cells, further confirming the regulation of WBLM by this locus. Our finding provides new insight into the genetics of WBLM and enhance our understanding of sarcopenia.
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17
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Lange S, Pinotsis N, Agarkova I, Ehler E. The M-band: The underestimated part of the sarcomere. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118440. [PMID: 30738787 PMCID: PMC7023976 DOI: 10.1016/j.bbamcr.2019.02.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/16/2019] [Accepted: 02/05/2019] [Indexed: 12/20/2022]
Abstract
The sarcomere is the basic unit of the myofibrils, which mediate skeletal and cardiac Muscle contraction. Two transverse structures, the Z-disc and the M-band, anchor the thin (actin and associated proteins) and thick (myosin and associated proteins) filaments to the elastic filament system composed of titin. A plethora of proteins are known to be integral or associated proteins of the Z-disc and its structural and signalling role in muscle is better understood, while the molecular constituents of the M-band and its function are less well defined. Evidence discussed here suggests that the M-band is important for managing force imbalances during active muscle contraction. Its molecular composition is fine-tuned, especially as far as the structural linkers encoded by members of the myomesin family are concerned and depends on the specific mechanical characteristics of each particular muscle fibre type. Muscle activity signals from the M-band to the nucleus and affects transcription of sarcomeric genes, especially via serum response factor (SRF). Due to its important role as shock absorber in contracting muscle, the M-band is also more and more recognised as a contributor to muscle disease.
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Affiliation(s)
- Stephan Lange
- Biomedical Research Facility 2, School of Medicine, University of California, San Diego, Medical Sciences Research Bldg, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA; University of Gothenburg, Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Irina Agarkova
- InSphero, Wagistrasse 27, CH-8952 Schlieren, Switzerland
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK; School of Cardiovascular Medicine and Sciences, British Heart Foundation Research Excellence Centre, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK.
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18
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Grogan A, Kontrogianni-Konstantopoulos A. Unraveling obscurins in heart disease. Pflugers Arch 2018; 471:735-743. [PMID: 30099631 DOI: 10.1007/s00424-018-2191-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 08/01/2018] [Indexed: 12/18/2022]
Abstract
Obscurins, expressed from the single OBSCN gene, are a family of giant, modular, cytoskeletal proteins that play key structural and regulatory roles in striated muscles. They were first implicated in the development of heart disease in 2007 when two missense mutations were found in a patient diagnosed with hypertrophic cardiomyopathy (HCM). Since then, the discovery of over a dozen missense, frameshift, and splicing mutations that are linked to various forms of cardiomyopathy, including HCM, dilated cardiomyopathy (DCM), and left ventricular non-compaction (LVNC), has highlighted OBSCN as a potential disease-causing gene. At this time, the functional consequences of the identified mutations remain largely elusive, and much work has yet to be done to characterize the disease mechanisms of pathological OBSCN variants. Herein, we describe the OBSCN mutations known to date, discuss their potential impact on disease development, and provide future directions in order to better understand the involvement of obscurins in heart disease.
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Affiliation(s)
- Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD, 21201, USA
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19
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Rajendran BK, Deng CX. Characterization of potential driver mutations involved in human breast cancer by computational approaches. Oncotarget 2018; 8:50252-50272. [PMID: 28477017 PMCID: PMC5564847 DOI: 10.18632/oncotarget.17225] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/26/2017] [Indexed: 02/06/2023] Open
Abstract
Breast cancer is the second most frequently occurring form of cancer and is also the second most lethal cancer in women worldwide. A genetic mutation is one of the key factors that alter multiple cellular regulatory pathways and drive breast cancer initiation and progression yet nature of these cancer drivers remains elusive. In this article, we have reviewed various computational perspectives and algorithms for exploring breast cancer driver mutation genes. Using both frequency based and mutational exclusivity based approaches, we identified 195 driver genes and shortlisted 63 of them as candidate drivers for breast cancer using various computational approaches. Finally, we conducted network and pathway analysis to explore their functions in breast tumorigenesis including tumor initiation, progression, and metastasis.
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Affiliation(s)
- Barani Kumar Rajendran
- Cancer Research Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Chu-Xia Deng
- Cancer Research Centre, Faculty of Health Sciences, University of Macau, Macau SAR, China
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20
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Wang L, Geist J, Grogan A, Hu LYR, Kontrogianni-Konstantopoulos A. Thick Filament Protein Network, Functions, and Disease Association. Compr Physiol 2018; 8:631-709. [PMID: 29687901 PMCID: PMC6404781 DOI: 10.1002/cphy.c170023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcomeres consist of highly ordered arrays of thick myosin and thin actin filaments along with accessory proteins. Thick filaments occupy the center of sarcomeres where they partially overlap with thin filaments. The sliding of thick filaments past thin filaments is a highly regulated process that occurs in an ATP-dependent manner driving muscle contraction. In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles. Consistent with this, mutations in the respective genes have been associated with idiopathic and congenital forms of skeletal and cardiac myopathies. In this review, we aim to summarize our current knowledge on the molecular structure, subcellular localization, interacting partners, function, modulation via posttranslational modifications, and disease involvement of these five major proteins that comprise the thick filament of striated muscle cells. © 2018 American Physiological Society. Compr Physiol 8:631-709, 2018.
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Affiliation(s)
- Li Wang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Li-Yen R. Hu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
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21
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Calender A, Rollat Farnier PA, Buisson A, Pinson S, Bentaher A, Lebecque S, Corvol H, Abou Taam R, Houdouin V, Bardel C, Roy P, Devouassoux G, Cottin V, Seve P, Bernaudin JF, Lim CX, Weichhart T, Valeyre D, Pacheco Y, Clement A, Nathan N. Whole exome sequencing in three families segregating a pediatric case of sarcoidosis. BMC Med Genomics 2018; 11:23. [PMID: 29510755 PMCID: PMC5839022 DOI: 10.1186/s12920-018-0338-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 02/19/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Sarcoidosis (OMIM 181000) is a multi-systemic granulomatous disorder of unknown origin. Despite multiple genome-wide association (GWAS) studies, no major pathogenic pathways have been identified to date. To find out relevant sarcoidosis predisposing genes, we searched for de novo and recessive mutations in 3 young probands with sarcoidosis and their healthy parents using a whole-exome sequencing (WES) methodology. METHODS From the SARCFAM project based on a national network collecting familial cases of sarcoidosis, we selected three families (trios) in which a child, despite healthy parents, develop the disease before age 15 yr. Each trio was genotyped by WES (Illumina HiSEQ 2500) and we selected the gene variants segregating as 1) new mutations only occurring in affected children and 2) as recessive traits transmitted from each parents. The identified coding variants were compared between the three families. Allelic frequencies and in silico functional results were analyzed using ExAC, SIFT and Polyphenv2 databases. The clinical and genetic studies were registered by the ClinicalTrials.gov - Protocol Registration and Results System (PRS) ( https://clinicaltrials.gov ) receipt under the reference NCT02829853 and has been approved by the ethical committee (CPP LYON SUD EST - 2 - REF IRB 00009118 - September 21, 2016). RESULTS We identified 37 genes sharing coding variants occurring either as recessive mutations in at least 2 trios or de novo mutations in one of the three affected children. The genes were classified according to their potential roles in immunity related pathways: 9 to autophagy and intracellular trafficking, 6 to G-proteins regulation, 4 to T-cell activation, 4 to cell cycle and immune synapse, 2 to innate immunity. Ten of the 37 genes were studied in a bibliographic way to evaluate the functional link with sarcoidosis. CONCLUSIONS Whole exome analysis of case-parent trios is useful for the identification of genes predisposing to complex genetic diseases as sarcoidosis. Our data identified 37 genes that could be putatively linked to a pediatric form of sarcoidosis in three trios. Our in-depth focus on 10 of these 37 genes may suggest that the formation of the characteristic lesion in sarcoidosis, granuloma, results from combined deficits in autophagy and intracellular trafficking (ex: Sec16A, AP5B1 and RREB1), G-proteins regulation (ex: OBSCN, CTTND2 and DNAH11), T-cell activation (ex: IDO2, IGSF3), mitosis and/or immune synapse (ex: SPICE1 and KNL1). The significance of these findings needs to be confirmed by functional tests on selected gene variants.
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Affiliation(s)
- Alain Calender
- Genetics Department, Hospices Civils de LYON (HCL), University Hospital, East Pathology Center, LYON, B-A3, 59 Bld Pinel, 69677 BRON Cedex, France
- Inflammation & Immunity of the Respiratory Epithelium - EA7426 (PI3) – South Medical University Hospital – Lyon 1 Claude Bernard University, 165 Chemin du Grand Revoyet, 69310 Pierre-Bénite, France
| | | | - Adrien Buisson
- Genetics Department, Hospices Civils de LYON (HCL), University Hospital, East Pathology Center, LYON, B-A3, 59 Bld Pinel, 69677 BRON Cedex, France
| | - Stéphane Pinson
- Genetics Department, Hospices Civils de LYON (HCL), University Hospital, East Pathology Center, LYON, B-A3, 59 Bld Pinel, 69677 BRON Cedex, France
| | - Abderrazzaq Bentaher
- Inflammation & Immunity of the Respiratory Epithelium - EA7426 (PI3) – South Medical University Hospital – Lyon 1 Claude Bernard University, 165 Chemin du Grand Revoyet, 69310 Pierre-Bénite, France
| | - Serge Lebecque
- Cancer Research Center, INSERM U-1052, CNRS 5286, 69008 Lyon, France
| | - Harriet Corvol
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Trousseau, AP-HP, INSERM UMR-S938, Sorbonne University, Paris, France
| | - Rola Abou Taam
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Necker, Paris, France
| | - Véronique Houdouin
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Robert Debré, INSERM U-1142, University Paris Diderot VII, Paris, France
| | - Claire Bardel
- Department of biostatistics, University Hospital, Hospices Civils de LYON (HCL), Lyon, France
| | - Pascal Roy
- Department of biostatistics, University Hospital, Hospices Civils de LYON (HCL), Lyon, France
| | - Gilles Devouassoux
- Department of Pulmonology, University Hospital, Hôpital Croix Rousse, Lyon, France
| | - Vincent Cottin
- Department of Pulmonology, University Hospital, Hôpital Louis Pradel, Lyon, France
| | - Pascal Seve
- Department of Internal medicine, University Hospital, Hôpital Croix Rousse, Lyon, France
| | | | - Clarice X. Lim
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Währinger Straße 10, 1090 Vienna, Austria
| | - Thomas Weichhart
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Währinger Straße 10, 1090 Vienna, Austria
| | - Dominique Valeyre
- EA2363, University Paris 13, COMUE Sorbonne-Paris-Cité, 74 rue Marcel Cachin, 93009 Bobigny, France
- Assistance Publique Hôpitaux de Paris, Department of Pulmonology, Avicenne University Hospital, 93009 Bobigny, France
| | - Yves Pacheco
- Inflammation & Immunity of the Respiratory Epithelium - EA7426 (PI3) – South Medical University Hospital – Lyon 1 Claude Bernard University, 165 Chemin du Grand Revoyet, 69310 Pierre-Bénite, France
| | - Annick Clement
- AP-HP Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Trousseau, INSERM UMR-S933, Sorbonne University, Paris, France
| | - Nadia Nathan
- AP-HP Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Trousseau, INSERM UMR-S933, Sorbonne University, Paris, France
| | - in the frame of GSF (Groupe Sarcoïdose France)
- Genetics Department, Hospices Civils de LYON (HCL), University Hospital, East Pathology Center, LYON, B-A3, 59 Bld Pinel, 69677 BRON Cedex, France
- Department of biostatistics, University Hospital, Hospices Civils de LYON (HCL), Lyon, France
- Inflammation & Immunity of the Respiratory Epithelium - EA7426 (PI3) – South Medical University Hospital – Lyon 1 Claude Bernard University, 165 Chemin du Grand Revoyet, 69310 Pierre-Bénite, France
- Cancer Research Center, INSERM U-1052, CNRS 5286, 69008 Lyon, France
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Trousseau, AP-HP, INSERM UMR-S938, Sorbonne University, Paris, France
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Necker, Paris, France
- Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Robert Debré, INSERM U-1142, University Paris Diderot VII, Paris, France
- Department of Pulmonology, University Hospital, Hôpital Croix Rousse, Lyon, France
- Department of Pulmonology, University Hospital, Hôpital Louis Pradel, Lyon, France
- Department of Internal medicine, University Hospital, Hôpital Croix Rousse, Lyon, France
- Histology and Tumor Biology, ER2 UPMC, Hôpital Tenon, Paris, France
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Währinger Straße 10, 1090 Vienna, Austria
- EA2363, University Paris 13, COMUE Sorbonne-Paris-Cité, 74 rue Marcel Cachin, 93009 Bobigny, France
- Assistance Publique Hôpitaux de Paris, Department of Pulmonology, Avicenne University Hospital, 93009 Bobigny, France
- AP-HP Pediatric pulmonology and Reference Center for rare lung diseases RespiRare, Hôpital Trousseau, INSERM UMR-S933, Sorbonne University, Paris, France
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Randazzo D, Pierantozzi E, Rossi D, Sorrentino V. The potential of obscurin as a therapeutic target in muscle disorders. Expert Opin Ther Targets 2017; 21:897-910. [DOI: 10.1080/14728222.2017.1361931] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Davide Randazzo
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda
| | - Enrico Pierantozzi
- Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Daniela Rossi
- Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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23
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Abstract
The inherited cardiomyopathies, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and left ventricular non-compaction (LVNC), have been frequently associated with mutations in sarcomeric proteins. In recent years, advances in DNA sequencing technology has allowed the study of the giant proteins of the sarcomere, such as titin and nebulin. Obscurin has been somewhat neglected in these studies, largely because its functional role is far from clear, although there was an isolated report in 2007 of obscurin mutations associated with HCM. Recently, whole exome sequencing methodology (WES) has been used to address mutations in OBSCN, the gene for obscurin, and OBSCN variants were found to be relatively common in inherited cardiomyopathies. In different studies, 5 OBSCN unique variants have been found in a group of 30 end-stage failing hearts, 6 OBSCN unique variants in 74 HCM cases and 3 OBSCN unique variants in 10 LVNC patients. As yet, the number of known potentially disease-causing OBSCN variants is quite small. The reason for this is that mutations in the OBSCN gene have not been recognised as potentially disease-causing until recently, and were not included in large-scale genetic surveys. OBSCN mutations may be causative of HCM, DCM and LVNC and other cardiomyopathies, or they may work in concert with other variants in the same or other genes to initiate the pathology. Currently, the function of obscurin is not well understood, but we anticipate that many more OBSCN variants linked to cardiomyopathy will be found when the large cohorts of patient sequences available are tested. It is to be hoped that the establishment of the importance of obscurin in pathology will stimulate a thorough investigation of obscurin function.
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Manring HR, Carter OA, Ackermann MA. Obscure functions: the location-function relationship of obscurins. Biophys Rev 2017; 9:245-258. [PMID: 28510116 DOI: 10.1007/s12551-017-0254-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/05/2017] [Indexed: 12/18/2022] Open
Abstract
The obscurin family of polypeptides is essential for normal striated muscle function and contributes to the pathogenesis of fatal diseases, including cardiomyopathies and cancers. The single mammalian obscurin gene, OBSCN, gives rise to giant (∼800 kDa) and smaller (∼40-500 kDa) proteins that are composed of tandem adhesion and signaling motifs. Mammalian obscurin proteins are expressed in a variety of cell types, including striated muscles, and localize to distinct subcellular compartments where they contribute to diverse cellular processes. Obscurin homologs in Caenorhabditis elegans and Drosophila possess a similar domain architecture and are also expressed in striated muscles. The long sought after question, "what does obscurin do?" is complex and cannot be addressed without taking into consideration the subcellular distribution of these proteins and local isoform concentration. Herein, we present an overview of the functions of obscurins and begin to define the intricate relationship between their subcellular distributions and functions in striated muscles.
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Affiliation(s)
- Heather R Manring
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA
| | - Olivia A Carter
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA.,Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA
| | - Maegen A Ackermann
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA. .,Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Ohio State University, Columbus, OH, 43210, USA.
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25
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Abstract
Striated cardiac and skeletal muscles play very different roles in the body, but they are similar at the molecular level. In particular, contraction, regardless of the type of muscle, is a precise and complex process involving the integral protein myofilaments and their associated regulatory components. The smallest functional unit of muscle contraction is the sarcomere. Within the sarcomere can be found a sophisticated ensemble of proteins associated with the thick filaments (myosin, myosin binding protein-C, titin, and obscurin) and thin myofilaments (actin, troponin, tropomyosin, nebulin, and nebulette). These parallel thick and thin filaments slide across one another, pulling the two ends of the sarcomere together to regulate contraction. More specifically, the regulation of both timing and force of contraction is accomplished through an intricate network of intra- and interfilament interactions belonging to each myofilament. This review introduces the sarcomere proteins involved in striated muscle contraction and places greater emphasis on the more recently identified and less well-characterized myofilaments: cardiac myosin binding protein-C, titin, nebulin, and obscurin. © 2017 American Physiological Society. Compr Physiol 7:675-692, 2017.
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Affiliation(s)
- Brian Leei Lin
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Taejeong Song
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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26
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Qadota H, Mayans O, Matsunaga Y, McMurry JL, Wilson KJ, Kwon GE, Stanford R, Deehan K, Tinley TL, Ngwa VM, Benian GM. The SH3 domain of UNC-89 (obscurin) interacts with paramyosin, a coiled-coil protein, in Caenorhabditis elegans muscle. Mol Biol Cell 2016; 27:1606-20. [PMID: 27009202 PMCID: PMC4865318 DOI: 10.1091/mbc.e15-09-0675] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 03/16/2016] [Accepted: 03/16/2016] [Indexed: 11/11/2022] Open
Abstract
UNC-89 is a giant polypeptide located at the sarcomeric M-line of Caenorhabditis elegans muscle. The human homologue is obscurin. To understand how UNC-89 is localized and functions, we have been identifying its binding partners. Screening a yeast two-hybrid library revealed that UNC-89 interacts with paramyosin. Paramyosin is an invertebrate-specific coiled-coil dimer protein that is homologous to the rod portion of myosin heavy chains and resides in thick filament cores. Minimally, this interaction requires UNC-89's SH3 domain and residues 294-376 of paramyosin and has a KD of ∼1.1 μM. In unc-89 loss-of-function mutants that lack the SH3 domain, paramyosin is found in accumulations. When the SH3 domain is overexpressed, paramyosin is mislocalized. SH3 domains usually interact with a proline-rich consensus sequence, but the region of paramyosin that interacts with UNC-89's SH3 is α-helical and lacks prolines. Homology modeling of UNC-89's SH3 suggests structural features that might be responsible for this interaction. The SH3-binding region of paramyosin contains a "skip residue," which is likely to locally unwind the coiled-coil and perhaps contributes to the binding specificity.
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Affiliation(s)
- Hiroshi Qadota
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Olga Mayans
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Yohei Matsunaga
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Jonathan L McMurry
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144
| | - Kristy J Wilson
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Grace E Kwon
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Rachel Stanford
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Kevin Deehan
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Tina L Tinley
- Department of Pathology, Emory University, Atlanta, GA 30322
| | - Verra M Ngwa
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144
| | - Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322
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27
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Loss of the obscurin-RhoGEF downregulates RhoA signaling and increases microtentacle formation and attachment of breast epithelial cells. Oncotarget 2015; 5:8558-68. [PMID: 25261370 PMCID: PMC4226704 DOI: 10.18632/oncotarget.2338] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Obscurins are RhoGEF-containing proteins whose downregulation has been implicated in the development and progression of breast cancer. Herein, we aim to elucidate the mechanism for increased motility of obscurin-deficient cells. We show that shRNA-mediated obscurin downregulation in MCF10A cells leads to >50% reduction in RhoA activity relative to scramble control (shCtrl), as well as decreased phosphorylation of RhoA effectors, including myosin light chain phosphatase, myosin light chain, lim kinase, and cofilin, in both attached and suspended cells. These alterations result in decreased actomyosin contractility, allowing suspended cells to escape detachment-induced apoptosis. Moreover, ~40% of shObsc-expressing cells, but only ~10% of shCtrl-expressing cells, extend microtentacles, tubulin-based projections that mediate the attachment of circulating tumor cells to endothelium. Indeed, we show that MCF10A cells expressing shObsc attach in vitro more readily than shCtrl cells, an advantage that persists following taxane exposure. Overall, our data suggest that loss of obscurins may represent a substantial selective advantage for breast epithelial cells during metastasis, and that treatment with paclitaxel may exacerbate this advantage by preferentially allowing obscurin-deficient, stem-like cells to attach to the endothelium of distant sites, a first step towards colonizing metastatic tumors.
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28
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The sarcomeric M-region: a molecular command center for diverse cellular processes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:714197. [PMID: 25961035 PMCID: PMC4413555 DOI: 10.1155/2015/714197] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
The sarcomeric M-region anchors thick filaments and withstands the mechanical stress of contractions by deformation, thus enabling distribution of physiological forces along the length of thick filaments. While the role of the M-region in supporting myofibrillar structure and contractility is well established, its role in mediating additional cellular processes has only recently started to emerge. As such, M-region is the hub of key protein players contributing to cytoskeletal remodeling, signal transduction, mechanosensing, metabolism, and proteasomal degradation. Mutations in genes encoding M-region related proteins lead to development of severe and lethal cardiac and skeletal myopathies affecting mankind. Herein, we describe the main cellular processes taking place at the M-region, other than thick filament assembly, and discuss human myopathies associated with mutant or truncated M-region proteins.
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29
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Babur Ö, Gönen M, Aksoy BA, Schultz N, Ciriello G, Sander C, Demir E. Systematic identification of cancer driving signaling pathways based on mutual exclusivity of genomic alterations. Genome Biol 2015; 16:45. [PMID: 25887147 PMCID: PMC4381444 DOI: 10.1186/s13059-015-0612-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/10/2015] [Indexed: 12/21/2022] Open
Abstract
We present a novel method for the identification of sets of mutually exclusive gene alterations in a given set of genomic profiles. We scan the groups of genes with a common downstream effect on the signaling network, using a mutual exclusivity criterion that ensures that each gene in the group significantly contributes to the mutual exclusivity pattern. We test the method on all available TCGA cancer genomics datasets, and detect multiple previously unreported alterations that show significant mutual exclusivity and are likely to be driver events.
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Affiliation(s)
- Özgün Babur
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
| | - Mithat Gönen
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, 10065, USA.
| | - Bülent Arman Aksoy
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
- Tri-Institutional Training Program in Computational Biology and Medicine, 1275 York Avenue, New York, 10065, USA.
| | - Nikolaus Schultz
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
| | - Giovanni Ciriello
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
| | - Chris Sander
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
| | - Emek Demir
- Computational Biology Center, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 460, New York, 10065, USA.
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30
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Shriver M, Stroka KM, Vitolo MI, Martin S, Huso DL, Konstantopoulos K, Kontrogianni-Konstantopoulos A. Loss of giant obscurins from breast epithelium promotes epithelial-to-mesenchymal transition, tumorigenicity and metastasis. Oncogene 2014; 34:4248-59. [PMID: 25381817 DOI: 10.1038/onc.2014.358] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 09/03/2014] [Accepted: 09/04/2014] [Indexed: 02/07/2023]
Abstract
Obscurins, encoded by the single OBSCN gene, are giant cytoskeletal proteins with structural and regulatory roles. The OBSCN gene is highly mutated in different types of cancers. Loss of giant obscurins from breast epithelial cells confers them with a survival and growth advantage, following exposure to DNA-damaging agents. Here we demonstrate that the expression levels and subcellular distribution of giant obscurins are altered in human breast cancer biopsies compared with matched normal samples. Stable clones of non-tumorigenic MCF10A cells lacking giant obscurins fail to form adhesion junctions, undergo epithelial-to-mesenchymal transition and generate >100-μm mammospheres bearing markers of cancer-initiating cells. Obscurin-knockdown MCF10A cells display markedly increased motility as a sheet in 2-dimensional (2D) substrata and individually in confined spaces and invasion in 3D matrices. In line with these observations, actin filaments redistribute to extending filopodia where they exhibit increased dynamics. MCF10A cells that stably express the K-Ras oncogene and obscurin short hairpin RNA (shRNA), but not scramble control shRNA, exhibit increased primary tumor formation and lung colonization after subcutaneous and tail vein injections, respectively. Collectively, our findings reveal that loss of giant obscurins from breast epithelium results in disruption of the cell-cell contacts and acquisition of a mesenchymal phenotype that leads to enhanced tumorigenesis, migration and invasiveness in vitro and in vivo.
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Affiliation(s)
- M Shriver
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - K M Stroka
- 1] Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA [2] Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, USA [3] Johns Hopkins Physical Sciences-Oncology Center, The Johns Hopkins University, Baltimore, MD, USA
| | - M I Vitolo
- Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - S Martin
- Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - D L Huso
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University and The Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - K Konstantopoulos
- 1] Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA [2] Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, USA [3] Johns Hopkins Physical Sciences-Oncology Center, The Johns Hopkins University, Baltimore, MD, USA
| | - A Kontrogianni-Konstantopoulos
- 1] Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA [2] Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
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31
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Miller NLG, Kleinschmidt EG, Schlaepfer DD. RhoGEFs in cell motility: novel links between Rgnef and focal adhesion kinase. Curr Mol Med 2014; 14:221-34. [PMID: 24467206 DOI: 10.2174/1566524014666140128110339] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 07/08/2013] [Accepted: 12/02/2013] [Indexed: 11/22/2022]
Abstract
Rho guanine exchange factors (GEFs) are a large, diverse family of proteins defined by their ability to catalyze the exchange of GDP for GTP on small GTPase proteins such as Rho family members. GEFs act as integrators from varied intra- and extracellular sources to promote spatiotemporal activity of Rho GTPases that control signaling pathways regulating cell proliferation and movement. Here we review recent studies elucidating roles of RhoGEF proteins in cell motility. Emphasis is placed on Dbl-family GEFs and connections to development, integrin signaling to Rho GTPases regulating cell adhesion and movement, and how these signals may enhance tumor progression. Moreover, RhoGEFs have additional domains that confer distinctive functions or specificity. We will focus on a unique interaction between Rgnef (also termed Arhgef28 or p190RhoGEF) and focal adhesion kinase (FAK), a non-receptor tyrosine kinase that controls migration properties of normal and tumor cells. This Rgnef-FAK interaction activates canonical GEF-dependent RhoA GTPase activity to govern contractility and also functions as a scaffold in a GEF-independent manner to enhance FAK activation. Recent studies have also brought to light the importance of specific regions within the Rgnef pleckstrin homology (PH) domain for targeting the membrane. As revealed by ongoing Rgnef-FAK investigations, exploring GEF roles in cancer will yield fundamental new information on the molecular mechanisms promoting tumor spread and metastasis.
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Affiliation(s)
| | | | - D D Schlaepfer
- University of California San Diego, Moores Cancer Center, Department of Reproductive Medicine, MC 0803, 3855 Health Sciences Dr., La Jolla, CA 92093 USA.
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32
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Obscurins: Goliaths and Davids take over non-muscle tissues. PLoS One 2014; 9:e88162. [PMID: 24516603 PMCID: PMC3916441 DOI: 10.1371/journal.pone.0088162] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/03/2014] [Indexed: 12/11/2022] Open
Abstract
Obscurins comprise a family of proteins originally identified in striated muscles, where they play essential roles in myofibrillogenesis, cytoskeletal organization, and Ca2+ homeostasis. They are encoded by the single OBSCN gene, and are composed of tandem adhesion domains and signaling motifs. To date, two giant obscurin isoforms have been described in detail that differ only at the extreme COOH-terminus; while obscurin-A (∼720 kDa) contains a non-modular COOH-terminus that harbors binding sites for the adaptor proteins ankyrins, obscurin-B (∼870 kDa) contains two COOH-terminal serine-threonine kinase domains preceded by adhesion motifs. Besides the two known giant obscurins, a thorough search of transcript databases suggests that complex alternative splicing of the obscurin transcript results in the generation of additional giant as well as small isoforms with molecular masses ranging between ∼50–970 kDa. These novel isoforms share common domains with the characterized isoforms, but also contain unique regions. Using a panel of highly specific antibodies directed against epitopes spanning the entire length of giant obscurins, we employed western blotting and immunohistochemistry to perform a systematic and comprehensive characterization of the expression profile of obscurins in muscle and non-muscle tissues. Our studies demonstrate for the first time that obscurins are not restricted to striated muscles, but are abundantly expressed in several tissues and organs including brain, skin, kidney, liver, spleen, and lung. While some obscurin isoforms are ubiquitously expressed, others are preferentially present in specific tissues and organs. Moreover, obscurins are present in select structures and cell types where they assume nuclear, cytosolic, and membrane distributions. Given the ubiquitous expression of some obscurins, along with the preferential expression of others, it becomes apparent that obscurins may play common and unique roles, respectively, in the regulation and maintenance of cell homeostasis in various tissues and organs throughout the body.
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33
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Abstract
Giant muscle proteins (e.g., titin, nebulin, and obscurin) play a seminal role in muscle elasticity, stretch response, and sarcomeric organization. Each giant protein consists of multiple tandem structural domains, usually arranged in a modular fashion spanning 500 kDa to 4 MDa. Although many of the domains are similar in structure, subtle differences create a unique function of each domain. Recent high and low resolution structural and dynamic studies now suggest more nuanced overall protein structures than previously realized. These findings show that atomic structure, interactions between tandem domains, and intrasarcomeric environment all influence the shape, motion, and therefore function of giant proteins. In this article we will review the current understanding of titin, obscurin, and nebulin structure, from the atomic level through the molecular level.
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Affiliation(s)
- Logan C Meyer
- Department of Chemistry and Biochemistry, James Madison University Harrisonburg, VA, USA
| | - Nathan T Wright
- Department of Chemistry and Biochemistry, James Madison University Harrisonburg, VA, USA
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34
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Temmerman K, Simon B, Wilmanns M. Structural and functional diversity in the activity and regulation of DAPK-related protein kinases. FEBS J 2013; 280:5533-50. [PMID: 23745726 DOI: 10.1111/febs.12384] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/06/2013] [Accepted: 06/07/2013] [Indexed: 11/30/2022]
Abstract
Within the large group of calcium/calmodulin-dependent protein kinases (CAMKs) of the human kinome, there is a distinct branch of highly related kinases that includes three families: death-associated protein-related kinases, myosin light-chain-related kinases and triple functional domain protein-related kinases. In this review, we refer to these collectively as DMT kinases. There are several functional features that span the three families, such as a broad involvement in apoptotic processes, cytoskeletal association and cellular plasticity. Other CAMKs contain a highly conserved HRD motif, which is a prerequisite for kinase regulation through activation-loop phosphorylation, but in all 16 members of the DMT branch, this is replaced by an HF/LD motif. This DMT kinase signature motif substitutes phosphorylation-dependent active-site interactions with a local hydrophobic core that maintains an active kinase conformation. Only about half of the DMT kinases have an additional autoregulatory domain, C-terminal to the kinase domain that binds calcium/calmodulin in order to regulate kinase activity. Protein substrates have been identified for some of the DMT kinases, but little is known about the mechanism of recognition. Substrate conformation could be an equally important parameter in substrate recognition as specific preferences in sequence position. Taking the data together, this kinase branch encapsulates a treasure trove of features that renders it distinct from many other protein kinases and calls for future research activities in this field.
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35
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Randazzo D, Giacomello E, Lorenzini S, Rossi D, Pierantozzi E, Blaauw B, Reggiani C, Lange S, Peter AK, Chen J, Sorrentino V. Obscurin is required for ankyrinB-dependent dystrophin localization and sarcolemma integrity. ACTA ACUST UNITED AC 2013; 200:523-36. [PMID: 23420875 PMCID: PMC3575540 DOI: 10.1083/jcb.201205118] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Obscurin contributes to the organization of subsarcolemma microtubules, localization of dystrophin at costameres, and maintenance of sarcolemmal integrity in skeletal muscle fibers. Obscurin is a large myofibrillar protein that contains several interacting modules, one of which mediates binding to muscle-specific ankyrins. Interaction between obscurin and the muscle-specific ankyrin sAnk1.5 regulates the organization of the sarcoplasmic reticulum in striated muscles. Additional muscle-specific ankyrin isoforms, ankB and ankG, are localized at the subsarcolemma level, at which they contribute to the organization of dystrophin and β-dystroglycan at costameres. In this paper, we report that in mice deficient for obscurin, ankB was displaced from its localization at the M band, whereas localization of ankG at the Z disk was not affected. In obscurin KO mice, localization at costameres of dystrophin, but not of β-dystroglycan, was altered, and the subsarcolemma microtubule cytoskeleton was disrupted. In addition, these mutant mice displayed marked sarcolemmal fragility and reduced muscle exercise tolerance. Altogether, the results support a model in which obscurin, by targeting ankB at the M band, contributes to the organization of subsarcolemma microtubules, localization of dystrophin at costameres, and maintenance of sarcolemmal integrity.
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Affiliation(s)
- Davide Randazzo
- Molecular Medicine Section, Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy
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36
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Perry NA, Ackermann MA, Shriver M, Hu LYR, Kontrogianni-Konstantopoulos A. Obscurins: unassuming giants enter the spotlight. IUBMB Life 2013; 65:479-86. [PMID: 23512348 DOI: 10.1002/iub.1157] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/31/2013] [Indexed: 02/04/2023]
Abstract
Discovered about a decade ago, obscurin (~720 kDa) is a member of a family of giant proteins expressed in striated muscle that are essential for normal muscle function. Much of what we understand about obscurin stems from its functions in cardiac and skeletal muscle. However, recent evidence has indicated that variants of obscurin ("obscurins") are expressed in diverse cell types, where they contribute to distinct cellular processes. Dysfunction or abrogation of obscurins has also been implicated in the development of several pathological conditions, including cardiac hypertrophy and cancer. Herein, we present an overview of obscurins with an emphasis on novel findings that demonstrate their heretofore-unsuspected importance in cell signaling and disease progression.
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Affiliation(s)
- Nicole A Perry
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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37
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Qu Z, Yu J, Ruan Q. TGF-β1-induced LPP expression dependant on Rho kinase during differentiation and migration of bone marrow-derived smooth muscle progenitor cells. ACTA ACUST UNITED AC 2012; 32:459-465. [PMID: 22886954 DOI: 10.1007/s11596-012-0080-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Indexed: 12/24/2022]
Abstract
Lipoma preferred partner (LPP) has been identified as a protein which is highly selective for smooth muscle progenitor cells (SMPCs) and regulates differentiation and migration of SMPCs, but mechanisms of LPP expression are not elucidated clearly. The aim of the present study was to discuss the mechanisms by which LPP expression is regulated in the differentiation and migration of SMPCs induced by TGF-β1. It was found that TGF-β1 could significantly increase the expression of LPP, smooth muscle α-actin, smooth muscle myosin heavy chain (SM-MHC), and smoothelin in SMPCs. Moreover, inactivation of Rho kinase (ROK) with ROK inhibitors significantly inhibited LPP mRNA expression in TGF-β1-treated SMPCs and mouse aortic smooth muscle cells (MAoSMCs). At the same time, LPP silencing with short interfering RNA significantly decreased SMPCs migration. In conclusion, LPP appears to be a ROK-dependant SMPCs differentiation marker that plays a role in regulating SMPCs migration.
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Affiliation(s)
- Zhiling Qu
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jun Yu
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qiurong Ruan
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Large isoforms of UNC-89 (obscurin) are required for muscle cell architecture and optimal calcium release in Caenorhabditis elegans. PLoS One 2012; 7:e40182. [PMID: 22768340 PMCID: PMC3388081 DOI: 10.1371/journal.pone.0040182] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Accepted: 06/01/2012] [Indexed: 11/19/2022] Open
Abstract
Calcium, a ubiquitous intracellular signaling molecule, controls a diverse array of cellular processes. Consequently, cells have developed strategies to modulate the shape of calcium signals in space and time. The force generating machinery in muscle is regulated by the influx and efflux of calcium ions into the muscle cytoplasm. In order for efficient and effective muscle contraction to occur, calcium needs to be rapidly, accurately and reliably regulated. The mechanisms underlying this highly regulated process are not fully understood. Here, we show that the Caenorhabditis elegans homolog of the giant muscle protein obscurin, UNC-89, is required for normal muscle cell architecture. The large immunoglobulin domain-rich isoforms of UNC-89 are critical for sarcomere and sarcoplasmic reticulum organization. Furthermore, we have found evidence that this structural organization is crucial for excitation-contraction coupling in the body wall muscle, through the coordination of calcium signaling. Thus, our data implicates UNC-89 in maintaining muscle cell architecture and that this precise organization is essential for optimal calcium mobilization and efficient and effective muscle contraction.
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Lange S, Perera S, Teh P, Chen J. Obscurin and KCTD6 regulate cullin-dependent small ankyrin-1 (sAnk1.5) protein turnover. Mol Biol Cell 2012; 23:2490-504. [PMID: 22573887 PMCID: PMC3386213 DOI: 10.1091/mbc.e12-01-0052] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Small ankyrin-1 isoform 5 (sAnk1.5) turnover is regulated by posttranslational modification (ubiquitylation, neddylation, and acetylation), the presence of obscurin, and KCTD6 (a novel tissue-specific interaction partner). KCTD6 links sAnk1.5 to cullin-3. The absence of obscurin results in translocation of sAnk1.5/KCTD6 to the Z-disk and loss of sAnk1.5 on the protein level. Protein turnover through cullin-3 is tightly regulated by posttranslational modifications, the COP9 signalosome, and BTB/POZ-domain proteins that link cullin-3 to specific substrates for ubiquitylation. In this paper, we report how potassium channel tetramerization domain containing 6 (KCTD6) represents a novel substrate adaptor for cullin-3, effectively regulating protein levels of the muscle small ankyrin-1 isoform 5 (sAnk1.5). Binding of sAnk1.5 to KCTD6, and its subsequent turnover is regulated through posttranslational modification by nedd8, ubiquitin, and acetylation of C-terminal lysine residues. The presence of the sAnk1.5 binding partner obscurin, and mutation of lysine residues increased sAnk1.5 protein levels, as did knockdown of KCTD6 in cardiomyocytes. Obscurin knockout muscle displayed reduced sAnk1.5 levels and mislocalization of the sAnk1.5/KCTD6 complex. Scaffolding functions of obscurin may therefore prevent activation of the cullin-mediated protein degradation machinery and ubiquitylation of sAnk1.5 through sequestration of sAnk1.5/KCTD6 at the sarcomeric M-band, away from the Z-disk–associated cullin-3. The interaction of KCTD6 with ankyrin-1 may have implications beyond muscle for hereditary spherocytosis, as KCTD6 is also present in erythrocytes, and erythrocyte ankyrin isoforms contain its mapped minimal binding site.
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Affiliation(s)
- Stephan Lange
- School of Medicine, University of California, San Diego, La Jolla, CA 92093-0613, USA.
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Perry NA, Shriver M, Mameza MG, Grabias B, Balzer E, Kontrogianni-Konstantopoulos A. Loss of giant obscurins promotes breast epithelial cell survival through apoptotic resistance. FASEB J 2012; 26:2764-75. [PMID: 22441987 DOI: 10.1096/fj.12-205419] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Obscurins (∼70 - 870 kDa), encoded by the single OBSCN gene, are cytoskeletal proteins originally identified in striated muscles with structural and regulatory roles. Recently, analysis of 13,023 genes in breast and colorectal cancers identified OBSCN as one of the most frequently mutated genes, implicating it in cancer formation. Herein we studied the expression profile of obscurins in breast, colon, and skin cancer cell lines and their involvement in cell survival. Immunoblot analysis demonstrated significant reduction of obscurin proteins [corrected] in cancer cells, resulting from decreased mRNA levels and/or the presence of mutant transcripts. In normal epithelium, obscurins localize in cytoplasmic puncta, the cell membrane, and the nucleus. Accordingly, subcellular fractionation demonstrated the presence of 2 novel nuclear isoforms of ∼110 and ∼120 kDa. Nontumorigenic MCF10A breast epithelial cells stably transduced with shRNAs targeting giant obscurins exhibited increased viability (∼30%) and reduced apoptosis (∼20%) following exposure to the DNA-damaging agent etoposide. Quantitative RT-PCR further indicated that the antiapoptotic genes BAG4 and HAX1 were up-regulated (1.5- and 1.4-fold, respectively), whereas initiator caspase-9 and death caspase-3 transcripts were down-regulated (0.8- and 0.6-fold, respectively). Our findings are the first to pinpoint critical roles for obscurins in cancer development by contributing to the regulation of cell survival.
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Affiliation(s)
- Nicole A Perry
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. ako
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Benian GM, Epstein HF. Caenorhabditis elegans muscle: a genetic and molecular model for protein interactions in the heart. Circ Res 2011; 109:1082-95. [PMID: 21998299 DOI: 10.1161/circresaha.110.237685] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The nematode Caenorhabditis elegans has become established as a major experimental organism with applications to many biomedical research areas. The body wall muscle cells are a useful model for the study of human cardiomyocytes and their homologous structures and proteins. The ability to readily identify mutations affecting these proteins and structures in C elegans and to be able to rigorously characterize their genotypes and phenotypes at the cellular and molecular levels permits mechanistic studies of the responsible interactions relevant to the inherited human cardiomyopathies. Future work in C elegans muscle holds great promise in uncovering new mechanisms in the pathogenesis of these cardiac disorders.
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Affiliation(s)
- Guy M Benian
- Department of Pathology, Emory University, Atlanta, GA 30322, USA.
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Yu YM, Gibbs KM, Davila J, Campbell N, Sung S, Todorova TI, Otsuka S, Sabaawy HE, Hart RP, Schachner M. MicroRNA miR-133b is essential for functional recovery after spinal cord injury in adult zebrafish. Eur J Neurosci 2011; 33:1587-97. [PMID: 21447094 DOI: 10.1111/j.1460-9568.2011.07643.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) play important roles during development and also in adult organisms by regulating the expression of multiple target genes. Here, we studied the function of miR-133b during zebrafish spinal cord regeneration and show upregulation of miR-133b expression in regenerating neurons of the brainstem after transection of the spinal cord. miR-133b has been shown to promote tissue regeneration in other tissue, but its ability to do so in the nervous system has yet to be tested. Inhibition of miR-133b expression by antisense morpholino (MO) application resulted in impaired locomotor recovery and reduced regeneration of axons from neurons in the nucleus of the medial longitudinal fascicle, superior reticular formation and intermediate reticular formation. miR-133b targets the small GTPase RhoA, which is an inhibitor of axonal growth, as well as other neurite outgrowth-related molecules. Our results indicate that miR-133b is an important determinant in spinal cord regeneration of adult zebrafish through reduction in RhoA protein levels by direct interaction with its mRNA. While RhoA has been studied as a therapeutic target in spinal cord injury, this is the first demonstration of endogenous regulation of RhoA by a microRNA that is required for spinal cord regeneration in zebrafish. The ability of miR-133b to suppress molecules that inhibit axon regrowth may underlie the capacity for adult zebrafish to recover locomotor function after spinal cord injury.
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Affiliation(s)
- Young-Mi Yu
- W. M. Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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Busby B, Oashi T, Willis CD, Ackermann MA, Kontrogianni-Konstantopoulos A, Mackerell AD, Bloch RJ. Electrostatic interactions mediate binding of obscurin to small ankyrin 1: biochemical and molecular modeling studies. J Mol Biol 2011; 408:321-34. [PMID: 21333652 DOI: 10.1016/j.jmb.2011.01.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/25/2011] [Accepted: 01/28/2011] [Indexed: 10/18/2022]
Abstract
Small ankyrin 1 (sAnk1; also known as Ank1.5) is an integral protein of the sarcoplasmic reticulum (SR) in skeletal and cardiac muscle cells, where it is thought to bind to the C-terminal region of obscurin, a large modular protein that surrounds the contractile apparatus. Using fusion proteins in vitro, in combination with site-directed mutagenesis and surface plasmon resonance measurements, we previously showed that the binding site on sAnk1 for obscurin consists, in part, of six lysine and arginine residues. Here we show that four charged residues in the high-affinity binding site on obscurin for sAnk1 (between residues 6316 and 6345), consisting of three glutamates and a lysine, are necessary, but not sufficient, for this site on obscurin to bind to sAnk1 with high affinity. We also identify specific complementary mutations in sAnk1 that can partially or completely compensate for the changes in binding caused by charge-switching mutations in obscurin. We used molecular modeling to develop structural models of residues 6322-6339 of obscurin bound to sAnk1. The models, based on a combination of Brownian and molecular dynamics simulations, predict that the binding site on sAnk1 for obscurin is organized as two ankyrin-like repeats, with the last α-helical segment oriented at an angle to nearby helices, allowing lysine 6338 of obscurin to form an ionic interaction with aspartate 111 of sAnk1. This prediction was validated by double-mutant cycle experiments. Our results are consistent with a model in which electrostatic interactions between specific pairs of side chains on obscurin and sAnk1 promote binding and complex formation.
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Affiliation(s)
- Ben Busby
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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Iwama E, Tsuchimoto D, Iyama T, Sakumi K, Nakagawara A, Takayama K, Nakanishi Y, Nakabeppu Y. Cancer-related PRUNE2 protein is associated with nucleotides and is highly expressed in mature nerve tissues. J Mol Neurosci 2011; 44:103-14. [PMID: 21234814 DOI: 10.1007/s12031-010-9490-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 12/28/2010] [Indexed: 10/18/2022]
Abstract
Human PRUNE is thought to enhance the metastasis of tumor cells. We found that a hypothetical paralog of PRUNE, PRUNE2, binds to 8-oxo-GTP, an oxidized form of GTP. Hypothetical PRUNE2 gene consists of C9orf65 and BMCC1/BNIPXL, both of which are malignant tumor-associated genes. We isolated PRUNE2 complementary DNA and revealed that the protein is composed of 3,062 residues. C9orf65 and BMCC1/BNIPXL encode the N-terminal part (259 residues) and C-terminal part (2,729 residues) of PRUNE2, respectively. We demonstrated the endogenous full-length PRUNE2 protein (338 kDa) by Western blot and mass spectrometry. PRUNE2 bound to 8-oxo-GTP as well as GTP. The expression levels of human PRUNE2 and mouse Prune2 messenger RNA (mRNA) were highest in the dorsal root ganglia (DRG) and, to a lesser extent, in other nerve tissues. DRG neurons express higher levels of PRUNE2 in their soma compared with adjacent cells. In addition, their expression levels in the adult nerve tissues were higher than those in fetal or neonatal nerve tissues. The present study indicates that C9orf65 and BMCC1/BNIPXL are transcribed as PRUNE2 mRNA, which is translated to a large PRUNE2 protein. The nerve tissue-specific and post-development expression of PRUNE2/Prune2 suggests that PRUNE2 may contribute to the maintenance of mature nervous systems.
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Affiliation(s)
- Eiji Iwama
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
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Raeker MO, Bieniek AN, Ryan AS, Tsai HJ, Zahn KM, Russell MW. Targeted deletion of the zebrafish obscurin A RhoGEF domain affects heart, skeletal muscle and brain development. Dev Biol 2009; 337:432-43. [PMID: 19931525 DOI: 10.1016/j.ydbio.2009.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 10/28/2009] [Accepted: 11/11/2009] [Indexed: 10/20/2022]
Abstract
Obscurin is a giant structural and signaling protein that participates in the assembly and structural integrity of striated myofibrils. Previous work has examined the physical interactions between obscurin and other cytoskeletal elements but its in vivo role in cell signaling, including the functions of its RhoGTPase Exchange Factor (RhoGEF) domain have not been characterized. In this study, morpholino antisense oligonucleotides were used to create an in-frame deletion of the active site of the obscurin A RhoGEF domain in order to examine its functions in zebrafish development. Cardiac myocytes in the morphant embryos lacked the intercalated disks that were present in controls by 72 and, in the more severely affected embryos, the contractile filaments were not organized into mature sarcomeres. Neural abnormalities included delay or loss of retinal lamination. Rescue of the phenotype with co-injection of mini-obscurin A expression constructs demonstrated that the observed effects were due to the loss of small GTPase activation by obscurin A. The immature phenotype of the cardiac myocytes and the retinal neuroblasts observed in the morphant embryos suggests that obscurin A-mediated small GTPase signaling promotes tissue-specific cellular differentiation. This is the first demonstration of the importance of the obscurin A-mediated RhoGEF signaling in vertebrate organogenesis and highlights the central role of obscurin A in striated muscle and neural development.
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Affiliation(s)
- Maide O Raeker
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
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Kontrogianni-Konstantopoulos A, Ackermann MA, Bowman AL, Yap SV, Bloch RJ. Muscle giants: molecular scaffolds in sarcomerogenesis. Physiol Rev 2009; 89:1217-67. [PMID: 19789381 PMCID: PMC3076733 DOI: 10.1152/physrev.00017.2009] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Myofibrillogenesis in striated muscles is a highly complex process that depends on the coordinated assembly and integration of a large number of contractile, cytoskeletal, and signaling proteins into regular arrays, the sarcomeres. It is also associated with the stereotypical assembly of the sarcoplasmic reticulum and the transverse tubules around each sarcomere. Three giant, muscle-specific proteins, titin (3-4 MDa), nebulin (600-800 kDa), and obscurin (approximately 720-900 kDa), have been proposed to play important roles in the assembly and stabilization of sarcomeres. There is a large amount of data showing that each of these molecules interacts with several to many different protein ligands, regulating their activity and localizing them to particular sites within or surrounding sarcomeres. Consistent with this, mutations in each of these proteins have been linked to skeletal and cardiac myopathies or to muscular dystrophies. The evidence that any of them plays a role as a "molecular template," "molecular blueprint," or "molecular ruler" is less definitive, however. Here we review the structure and function of titin, nebulin, and obscurin, with the literature supporting a role for them as scaffolding molecules and the contradictory evidence regarding their roles as molecular guides in sarcomerogenesis.
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