1
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Stroik D, Gregorich ZR, Raza F, Ge Y, Guo W. Titin: roles in cardiac function and diseases. Front Physiol 2024; 15:1385821. [PMID: 38660537 PMCID: PMC11040099 DOI: 10.3389/fphys.2024.1385821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The giant protein titin is an essential component of muscle sarcomeres. A single titin molecule spans half a sarcomere and mediates diverse functions along its length by virtue of its unique domains. The A-band of titin functions as a molecular blueprint that defines the length of the thick filaments, the I-band constitutes a molecular spring that determines cell-based passive stiffness, and various domains, including the Z-disk, I-band, and M-line, serve as scaffolds for stretch-sensing signaling pathways that mediate mechanotransduction. This review aims to discuss recent insights into titin's functional roles and their relationship to cardiac function. The role of titin in heart diseases, such as dilated cardiomyopathy and heart failure with preserved ejection fraction, as well as its potential as a therapeutic target, is also discussed.
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Affiliation(s)
- Dawson Stroik
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Zachery R. Gregorich
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Farhan Raza
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Ying Ge
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Wei Guo
- Cellular and Molecular Pathology Program, Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
- Department of Animal and Dairy Sciences, College of Agriculture and Life Science, University of Wisconsin-Madison, Madison, WI, United States
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2
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Nakamura F. The Role of Mechanotransduction in Contact Inhibition of Locomotion and Proliferation. Int J Mol Sci 2024; 25:2135. [PMID: 38396812 PMCID: PMC10889191 DOI: 10.3390/ijms25042135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024] Open
Abstract
Contact inhibition (CI) represents a crucial tumor-suppressive mechanism responsible for controlling the unbridled growth of cells, thus preventing the formation of cancerous tissues. CI can be further categorized into two distinct yet interrelated components: CI of locomotion (CIL) and CI of proliferation (CIP). These two components of CI have historically been viewed as separate processes, but emerging research suggests that they may be regulated by both distinct and shared pathways. Specifically, recent studies have indicated that both CIP and CIL utilize mechanotransduction pathways, a process that involves cells sensing and responding to mechanical forces. This review article describes the role of mechanotransduction in CI, shedding light on how mechanical forces regulate CIL and CIP. Emphasis is placed on filamin A (FLNA)-mediated mechanotransduction, elucidating how FLNA senses mechanical forces and translates them into crucial biochemical signals that regulate cell locomotion and proliferation. In addition to FLNA, trans-acting factors (TAFs), which are proteins or regulatory RNAs capable of directly or indirectly binding to specific DNA sequences in distant genes to regulate gene expression, emerge as sensitive players in both the mechanotransduction and signaling pathways of CI. This article presents methods for identifying these TAF proteins and profiling the associated changes in chromatin structure, offering valuable insights into CI and other biological functions mediated by mechanotransduction. Finally, it addresses unanswered research questions in these fields and delineates their possible future directions.
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Affiliation(s)
- Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
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3
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Kellermayer D, Tordai H, Kiss B, Török G, Péter DM, Sayour AA, Pólos M, Hartyánszky I, Szilveszter B, Labeit S, Gángó A, Bedics G, Bödör C, Radovits T, Merkely B, Kellermayer MS. Truncated titin is structurally integrated into the human dilated cardiomyopathic sarcomere. J Clin Invest 2024; 134:e169753. [PMID: 37962957 PMCID: PMC10763722 DOI: 10.1172/jci169753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/08/2023] [Indexed: 11/16/2023] Open
Abstract
Heterozygous (HET) truncating variant mutations in the TTN gene (TTNtvs), encoding the giant titin protein, are the most common genetic cause of dilated cardiomyopathy (DCM). However, the molecular mechanisms by which TTNtv mutations induce DCM are controversial. Here, we studied 127 clinically identified DCM human cardiac samples with next-generation sequencing (NGS), high-resolution gel electrophoresis, Western blot analysis, and super-resolution microscopy in order to dissect the structural and functional consequences of TTNtv mutations. The occurrence of TTNtv was found to be 15% in the DCM cohort. Truncated titin proteins matching, by molecular weight, the gene sequence predictions were detected in the majority of the TTNtv+ samples. Full-length titin was reduced in TTNtv+ compared with TTNtv- samples. Proteomics analysis of washed myofibrils and stimulated emission depletion (STED) super-resolution microscopy of myocardial sarcomeres labeled with sequence-specific anti-titin antibodies revealed that truncated titin was structurally integrated into the sarcomere. Sarcomere length-dependent anti-titin epitope position, shape, and intensity analyses pointed at possible structural defects in the I/A junction and the M-band of TTNtv+ sarcomeres, which probably contribute, possibly via faulty mechanosensor function, to the development of manifest DCM.
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Affiliation(s)
- Dalma Kellermayer
- Heart and Vascular Center
- Department of Biophysics and Radiation Biology, and
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | | | - Balázs Kiss
- Department of Biophysics and Radiation Biology, and
| | - György Török
- Department of Biophysics and Radiation Biology, and
| | | | | | | | | | | | - Siegfried Labeit
- DZHK Partnersite Mannheim-Heidelberg, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ambrus Gángó
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Gábor Bedics
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Csaba Bödör
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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4
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Mierke CT. Magnetic tweezers in cell mechanics. Methods Enzymol 2024; 694:321-354. [PMID: 38492957 DOI: 10.1016/bs.mie.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
The chapter provides an overview of the applications of magnetic tweezers in living cells. It discusses the advantages and disadvantages of magnetic tweezers technology with a focus on individual magnetic tweezers configurations, such as electromagnetic tweezers. Solutions to the disadvantages identified are also outlined. The specific role of magnetic tweezers in the field of mechanobiology, such as mechanosensitivity, mechano-allostery and mechanotransduction are also emphasized. The specific usage of magnetic tweezers in mechanically probing cells via specific cell surface receptors, such as mechanosensitive channels is discussed and why mechanical probing has revealed the opening and closing of the channels. Finally, the future direction of magnetic tweezers is presented.
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Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth System Sciences, Peter Debye Institute for Soft Matter Physics, Biological Physics Division, Leipzig University, Leipzig, Germany.
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5
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Tamborrini D, Wang Z, Wagner T, Tacke S, Stabrin M, Grange M, Kho AL, Rees M, Bennett P, Gautel M, Raunser S. Structure of the native myosin filament in the relaxed cardiac sarcomere. Nature 2023; 623:863-871. [PMID: 37914933 PMCID: PMC10665186 DOI: 10.1038/s41586-023-06690-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023]
Abstract
The thick filament is a key component of sarcomeres, the basic units of striated muscle1. Alterations in thick filament proteins are associated with familial hypertrophic cardiomyopathy and other heart and muscle diseases2. Despite the central importance of the thick filament, its molecular organization remains unclear. Here we present the molecular architecture of native cardiac sarcomeres in the relaxed state, determined by cryo-electron tomography. Our reconstruction of the thick filament reveals the three-dimensional organization of myosin, titin and myosin-binding protein C (MyBP-C). The arrangement of myosin molecules is dependent on their position along the filament, suggesting specialized capacities in terms of strain susceptibility and force generation. Three pairs of titin-α and titin-β chains run axially along the filament, intertwining with myosin tails and probably orchestrating the length-dependent activation of the sarcomere. Notably, whereas the three titin-α chains run along the entire length of the thick filament, titin-β chains do not. The structure also demonstrates that MyBP-C bridges thin and thick filaments, with its carboxy-terminal region binding to the myosin tails and directly stabilizing the OFF state of the myosin heads in an unforeseen manner. These results provide a foundation for future research investigating muscle disorders involving sarcomeric components.
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Affiliation(s)
- Davide Tamborrini
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Zhexin Wang
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Thorsten Wagner
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sebastian Tacke
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Markus Stabrin
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Michael Grange
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- Structural Biology, The Rosalind Franklin Institute, Didcot, UK
| | - Ay Lin Kho
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Martin Rees
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Pauline Bennett
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, Kings College London BHF Centre of Research Excellence, London, UK
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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6
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Wang G, Wu W, Lv X, Yan C, Lin P. Aberrant mRNA processing caused by splicing mutations in TTN-related neuromuscular disorders. J Hum Genet 2023; 68:777-782. [PMID: 37407718 DOI: 10.1038/s10038-023-01182-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 07/07/2023]
Abstract
Mutations in the TTN gene have been reported to be responsible for a range of neuromuscular disorders, including recessive distal myopathy and congenital myopathy (CM). Only five splicing mutations have been identified to induce aberrant mRNA splicing in TTN-related neuromuscular disorders. In our study, we described detailed clinical characteristics, muscle pathology and genetic analysis of two probands with TTN-related autosomal recessive neuromuscular disorders. Besides, we identified two novel intronic mutations, c.107377+1 G > C in intron 362 and c.19994-2 A > G in intron 68, in the two probands. Through cDNA analysis, we revealed the c.107377+1 G > C mutation induced retention of the entire intron 362, and the c.19994-2 A > G mutation triggered skipping of the first 11 bp of exon 69. Our study broadens the aberrant splicing spectrum of neuromuscular disorders caused by splicing mutations in the TTN gene.
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Affiliation(s)
- Guangyu Wang
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Wenjing Wu
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Xiaoqing Lv
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Chuanzhu Yan
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China
| | - Pengfei Lin
- Department of Neurology and Research Institute of Neuromuscular and Neurodegenerative Diseases, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, China.
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7
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Lepley LK, Stoneback L, Macpherson PC, Butterfield TA. Eccentric Exercise as a Potent Prescription for Muscle Weakness After Joint Injury. Exerc Sport Sci Rev 2023; 51:109-116. [PMID: 37093645 PMCID: PMC10330137 DOI: 10.1249/jes.0000000000000319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Lengthening contractions (i.e., eccentric contractions) are capable of uniquely triggering the nervous system and signaling pathways to promote tissue health/growth. This mode of exercise may be particularly potent for patients suffering from muscle weakness after joint injury. Here we provide a novel framework for eccentric exercise as a safe, effective mode of exercise prescription for muscle recovery.
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Affiliation(s)
| | - Luke Stoneback
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
| | - Peter C.D. Macpherson
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy A. Butterfield
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
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8
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Linke WA. Stretching the story of titin and muscle function. J Biomech 2023; 152:111553. [PMID: 36989971 DOI: 10.1016/j.jbiomech.2023.111553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023]
Abstract
The discovery of the giant protein titin, also known as connectin, dates almost half a century back. In this review, I recapitulate major advances in the discovery of the titin filaments and the recognition of their properties and function until today. I briefly discuss how our understanding of the layout and interactions of titin in muscle sarcomeres has evolved and review key facts about the titin sequence at the gene (TTN) and protein levels. I also touch upon properties of titin important for the stability of the contractile units and the assembly and maintenance of sarcomeric proteins. The greater part of my discussion centers around the mechanical function of titin in skeletal muscle. I cover milestones of research on titin's role in stretch-dependent passive tension development, recollect the reasons behind the enormous elastic diversity of titin, and provide an update on the molecular mechanisms of titin elasticity, details of which are emerging even now. I reflect on current knowledge of how muscle fibers behave mechanically if titin stiffness is removed and how titin stiffness can be dynamically regulated, such as by posttranslational modifications or calcium binding. Finally, I highlight novel and exciting, but still controversially discussed, insight into the role titin plays in active tension development, such as length-dependent activation and contraction from longer muscle lengths.
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Affiliation(s)
- Wolfgang A Linke
- Institute of Physiology II, University of Münster, Germany; Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Germany; German Centre for Cardiovascular Research, Berlin, Germany.
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9
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Zacharchenko T, Dorendorf T, Locker N, Van Dijk E, Katzemich A, Diederichs K, Bullard B, Mayans O. PK1 from Drosophila obscurin is an inactive pseudokinase with scaffolding properties. Open Biol 2023; 13:220350. [PMID: 37121260 PMCID: PMC10129394 DOI: 10.1098/rsob.220350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/23/2023] [Indexed: 05/02/2023] Open
Abstract
Obscurins are large filamentous proteins with crucial roles in the assembly, stability and regulation of muscle. Characteristic of these proteins is a tandem of two C-terminal kinase domains, PK1 and PK2, that are separated by a long intrinsically disordered sequence. The significance of this conserved domain arrangement is unknown. Our study of PK1 from Drosophila obscurin shows that this is a pseudokinase with features typical of the CAM-kinase family, but which carries a minimalistic regulatory tail that no longer binds calmodulin or has mechanosensory properties typical of other sarcomeric kinases. PK1 binds ATP with high affinity, but in the absence of magnesium and lacks detectable phosphotransfer activity. It also has a highly diverged active site, strictly conserved across arthropods, that might have evolved to accommodate an unconventional binder. We find that PK1 interacts with PK2, suggesting a functional relation to the latter. These findings lead us to speculate that PK1/PK2 form a pseudokinase/kinase dual system, where PK1 might act as an allosteric regulator of PK2 and where mechanosensing properties, akin to those described for regulatory tails in titin-like kinases, might now reside on the unstructured interkinase segment. We propose that the PK1-interkinase-PK2 region constitutes an integrated functional unit in obscurin proteins.
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Affiliation(s)
- Thomas Zacharchenko
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Till Dorendorf
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Evert Van Dijk
- Biosynth B.V., Zuidersluisweg 2, 8243 RC Lelystad, The Netherlands
| | | | - Kay Diederichs
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | | | - Olga Mayans
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
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10
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A Novel Nonsense Pathogenic TTN Variant Identified in a Patient with Severe Dilated Cardiomyopathy. Curr Issues Mol Biol 2023; 45:2422-2430. [PMID: 36975527 PMCID: PMC10047881 DOI: 10.3390/cimb45030157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
Both genetic and environmental factors contribute to the development of dilated cardiomyopathy. Among the genes involved, TTN mutations, including truncated variants, explain 25% of DCM cases. We performed genetic counseling and analysis on a 57-year-old woman diagnosed with severe DCM and presenting relevant acquired risk factors for DCM (hypertension, diabetes, smoking habit, and/or previous alcohol and cocaine abuse) and with a family history of both DCM and sudden cardiac death. The left ventricular systolic function, as assessed by standard echocardiography, was 20%. The genetic analysis performed using TruSight Cardio panel, including 174 genes related to cardiac genetic diseases, revealed a novel nonsense TTN variant (TTN:c.103591A > T, p.Lys34531*), falling within the M-band region of the titin protein. This region is known for its important role in maintaining the structure of the sarcomere and in promoting sarcomerogenesis. The identified variant was classified as likely pathogenic based on ACMG criteria. The current results support the need of genetic analysis in the presence of a family history, even when relevant acquired risk factors for DCM may have contributed to the severity of the disease.
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11
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Yang C, Guo J, Ni K, Wen K, Qin Y, Gu R, Wang C, Liu L, Pan Y, Li J, Luo M, Deng L. Mechanical Ventilation-Related High Stretch Mainly Induces Endoplasmic Reticulum Stress and Thus Mediates Inflammation Response in Cultured Human Primary Airway Smooth Muscle Cells. Int J Mol Sci 2023; 24:ijms24043811. [PMID: 36835223 PMCID: PMC9958795 DOI: 10.3390/ijms24043811] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/29/2023] [Accepted: 02/03/2023] [Indexed: 02/17/2023] Open
Abstract
Ventilator-induced lung injury (VILI) occurs in mechanically ventilated patients of respiratory disease and is typically characterized by airway inflammation. However, recent studies increasingly indicate that a major cause of VILI may be the excessive mechanical loading such as high stretch (>10% strain) on airway smooth muscle cells (ASMCs) due to mechanical ventilation (MV). Although ASMCs are the primary mechanosensitive cells in airways and contribute to various airway inflammation diseases, it is still unclear how they respond to high stretch and what mediates such a response. Therefore, we used whole genome-wide mRNA-sequencing (mRNA-Seq), bioinformatics, and functional identification to systematically analyze the mRNA expression profiles and signaling pathway enrichment of cultured human ASMCs exposed to high stretch (13% strain), aiming to screen the susceptible signaling pathway through which cells respond to high stretch. The data revealed that in response to high stretch, 111 mRNAs with count ≥100 in ASMCs were significantly differentially expressed (defined as DE-mRNAs). These DE-mRNAs are mainly enriched in endoplasmic reticulum (ER) stress-related signaling pathways. ER stress inhibitor (TUDCA) abolished high-stretch-enhanced mRNA expression of genes associated with ER stress, downstream inflammation signaling, and major inflammatory cytokines. These results demonstrate in a data-driven approach that in ASMCs, high stretch mainly induced ER stress and activated ER stress-related signaling and downstream inflammation response. Therefore, it suggests that ER stress and related signaling pathways in ASMCs may be potential targets for timely diagnosis and intervention of MV-related pulmonary airway diseases such as VILI.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Mingzhi Luo
- Correspondence: (M.L.); (L.D.); Tel.: +86-136-1611-9565 (M.L.); +86-136-8520-7009 (L.D.)
| | - Linhong Deng
- Correspondence: (M.L.); (L.D.); Tel.: +86-136-1611-9565 (M.L.); +86-136-8520-7009 (L.D.)
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12
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Mechanotransduction for Muscle Protein Synthesis via Mechanically Activated Ion Channels. Life (Basel) 2023; 13:life13020341. [PMID: 36836698 PMCID: PMC9962945 DOI: 10.3390/life13020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
Cell mechanotransduction, the ability to detect physical forces and convert them into a series of biochemical events, is important for a wide range of physiological processes. Cells express an array of mechanosensors transducing physical forces into intracellular signaling cascades, including ion channels. Ion channels that can be directly activated by mechanical cues are known as mechanically activated (MA), or stretch-activated (SA), channels. In response to repeated exposures to mechanical stimulation in the form of resistance training, enhanced protein synthesis and fiber hypertrophy are elicited in skeletal muscle, whereas a lack of mechanical stimuli due to inactivity/mechanical unloading leads to reduced muscle protein synthesis and fiber atrophy. To date, the role of MA channels in the transduction of mechanical load to intracellular signaling pathways regulating muscle protein synthesis is poorly described. This review article will discuss MA channels in striated muscle, their regulation, and putative roles in the anabolic processes in muscle cells/fibers in response to mechanical stimuli.
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13
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Beedle AEM, Garcia-Manyes S. The role of single protein elasticity in mechanobiology. NATURE REVIEWS. MATERIALS 2023; 8:10-24. [PMID: 37469679 PMCID: PMC7614781 DOI: 10.1038/s41578-022-00488-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 07/21/2023]
Abstract
In addition to biochemical signals and genetic considerations, mechanical forces are rapidly emerging as a master regulator of human physiology. Yet the molecular mechanisms that regulate force-induced functionalities across a wide range of scales, encompassing the cell, tissue or organ levels, are comparatively not so well understood. With the advent, development and refining of single molecule nanomechanical techniques, enabling to exquisitely probe the conformational dynamics of individual proteins under the effect of a calibrated force, we have begun to acquire a comprehensive knowledge on the rich plethora of physicochemical principles that regulate the elasticity of single proteins. Here we review the major advances underpinning our current understanding of how the elasticity of single proteins regulates mechanosensing and mechanotransduction. We discuss the present limitations and future challenges of such a prolific and burgeoning field.
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Affiliation(s)
- Amy EM Beedle
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
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14
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Martin AA, Thompson BR, Hahn D, Angulski ABB, Hosny N, Cohen H, Metzger JM. Cardiac Sarcomere Signaling in Health and Disease. Int J Mol Sci 2022; 23:16223. [PMID: 36555864 PMCID: PMC9782806 DOI: 10.3390/ijms232416223] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
The cardiac sarcomere is a triumph of biological evolution wherein myriad contractile and regulatory proteins assemble into a quasi-crystalline lattice to serve as the central point upon which cardiac muscle contraction occurs. This review focuses on the many signaling components and mechanisms of regulation that impact cardiac sarcomere function. We highlight the roles of the thick and thin filament, both as necessary structural and regulatory building blocks of the sarcomere as well as targets of functionally impactful modifications. Currently, a new focus emerging in the field is inter-myofilament signaling, and we discuss here the important mediators of this mechanism, including myosin-binding protein C and titin. As the understanding of sarcomere signaling advances, so do the methods with which it is studied. This is reviewed here through discussion of recent live muscle systems in which the sarcomere can be studied under intact, physiologically relevant conditions.
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Affiliation(s)
| | | | | | | | | | | | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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15
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Rasmussen NL, Kournoutis A, Lamark T, Johansen T. NBR1: The archetypal selective autophagy receptor. J Cell Biol 2022; 221:213552. [PMID: 36255390 PMCID: PMC9582228 DOI: 10.1083/jcb.202208092] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/24/2022] Open
Abstract
NBR1 was discovered as an autophagy receptor not long after the first described vertebrate autophagy receptor p62/SQSTM1. Since then, p62 has currently been mentioned in >10,000 papers on PubMed, while NBR1 is mentioned in <350 papers. Nonetheless, evolutionary analysis reveals that NBR1, and likely also selective autophagy, was present already in the last eukaryotic common ancestor (LECA), while p62 appears first in the early Metazoan lineage. Furthermore, yeast-selective autophagy receptors Atg19 and Atg34 represent NBR1 homologs. NBR1 is the main autophagy receptor in plants that do not contain p62, while most animal taxa contain both NBR1 and p62. Mechanistic studies are starting to shed light on the collaboration between mammalian NBR1 and p62 in the autophagic degradation of protein aggregates (aggrephagy). Several domains of NBR1 are involved in cargo recognition, and the list of known substrates for NBR1-mediated selective autophagy is increasing. Lastly, roles of NBR1 in human diseases such as proteinopathies and cancer are emerging.
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Affiliation(s)
- Nikoline Lander Rasmussen
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Athanasios Kournoutis
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Trond Lamark
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Terje Johansen
- Autophagy Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
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16
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LIM CHANGHYUN, NUNES EVERSONA, CURRIER BRADS, MCLEOD JONATHANC, THOMAS AARONCQ, PHILLIPS STUARTM. An Evidence-Based Narrative Review of Mechanisms of Resistance Exercise-Induced Human Skeletal Muscle Hypertrophy. Med Sci Sports Exerc 2022; 54:1546-1559. [PMID: 35389932 PMCID: PMC9390238 DOI: 10.1249/mss.0000000000002929] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Skeletal muscle plays a critical role in physical function and metabolic health. Muscle is a highly adaptable tissue that responds to resistance exercise (RE; loading) by hypertrophying, or during muscle disuse, RE mitigates muscle loss. Resistance exercise training (RET)-induced skeletal muscle hypertrophy is a product of external (e.g., RE programming, diet, some supplements) and internal variables (e.g., mechanotransduction, ribosomes, gene expression, satellite cells activity). RE is undeniably the most potent nonpharmacological external variable to stimulate the activation/suppression of internal variables linked to muscular hypertrophy or countering disuse-induced muscle loss. Here, we posit that despite considerable research on the impact of external variables on RET and hypertrophy, internal variables (i.e., inherent skeletal muscle biology) are dominant in regulating the extent of hypertrophy in response to external stimuli. Thus, identifying the key internal skeletal muscle-derived variables that mediate the translation of external RE variables will be pivotal to determining the most effective strategies for skeletal muscle hypertrophy in healthy persons. Such work will aid in enhancing function in clinical populations, slowing functional decline, and promoting physical mobility. We provide up-to-date, evidence-based perspectives of the mechanisms regulating RET-induced skeletal muscle hypertrophy.
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Affiliation(s)
- CHANGHYUN LIM
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
| | - EVERSON A. NUNES
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
- Department of Physiological Science, Federal University of Santa Catarina, Florianópolis, Santa-Catarina, BRAZIL
| | - BRAD S. CURRIER
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
| | - JONATHAN C. MCLEOD
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
| | - AARON C. Q. THOMAS
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
| | - STUART M. PHILLIPS
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
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17
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Veselov M, Uporov IV, Efremova MV, Le-Deygen IM, Prusov AN, Shchetinin IV, Savchenko AG, Golovin YI, Kabanov AV, Klyachko NL. Modulation of α-Chymotrypsin Conjugated to Magnetic Nanoparticles by the Non-Heating Low-Frequency Magnetic Field: Molecular Dynamics, Reaction Kinetics, and Spectroscopy Analysis. ACS OMEGA 2022; 7:20644-20655. [PMID: 35755395 PMCID: PMC9219078 DOI: 10.1021/acsomega.2c00704] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Enzymes conjugated to magnetic nanoparticles (MNPs) undergo changes in the catalytic activity of the non-heating low-frequency magnetic field (LFMF). We apply in silico simulations by molecular dynamics (MD) and in vitro spectroscopic analysis of the enzyme kinetics and secondary structure to study α-chymotrypsin (CT) conjugated to gold-coated iron oxide MNPs. The latter are functionalized by either carboxylic or amino group moieties to vary the points of enzyme attachment. The MD simulation suggests that application of the stretching force to the CT globule by its amino or carboxylic groups causes shrinkage of the substrate-binding site but little if any changes in the catalytic triad. Consistent with this, in CT conjugated to MNPs by either amino or carboxylic groups, LFMF alters the Michaelis-Menten constant but not the apparent catalytic constant k cat (= V max/[E]o). Irrespective of the point of conjugation to MNPs, the CT secondary structure was affected with nearly complete loss of α-helices and increase in the random structures in LFMF, as shown by attenuated total reflection Fourier transformed infrared spectroscopy. Both the catalytic activity and the protein structure of MNP-CT conjugates restored 3 h after the field exposure. We believe that such remotely actuated systems can find applications in advanced manufacturing, nanomedicine, and other areas.
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Affiliation(s)
- Maxim
M. Veselov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Igor V. Uporov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Maria V. Efremova
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- National
University of Science and Technology “MISIS”, Moscow 119049, Russia
- Department
of Applied Physics, Eindhoven University
of Technology, Eindhoven 5600 MB, The Netherlands
| | - Irina M. Le-Deygen
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | | | - Igor V. Shchetinin
- National
University of Science and Technology “MISIS”, Moscow 119049, Russia
| | | | - Yuri I. Golovin
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- G.R.
Derzhavin Tambov State University, Tambov 392000, Russia
| | - Alexander V. Kabanov
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Center
for
Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7362, United States
| | - Natalia L. Klyachko
- School
of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Center
for
Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7362, United States
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18
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Bogomolovas J, Gravenhorst P, Mayans O. Production and analysis of titin kinase: Exploiting active/inactive kinase homologs in pseudokinase validation. Methods Enzymol 2022; 667:147-181. [PMID: 35525541 DOI: 10.1016/bs.mie.2022.03.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protein pseudokinases are key regulators of the eukaryotic cell. Understanding their unconventional molecular mechanisms relies on deciphering their putative potential to perform phosphotransfer, their scaffolding properties and the nature of their regulation. Titin pseudokinase (TK) is the defining member of a family of poorly characterized muscle-specific kinases thought to act as sensors and transducers of mechanical signals in the sarcomere. The functional mechanisms of TK remain obscure due to the challenges posed by its production and analysis. Here, we provide guidelines and tailored research approaches for the study of TK, including profiting from its close structure-function relationship to the catalytically active homolog twitchin kinase (TwcK) from C. elegans. We describe a methodological pipeline to produce recombinant TK and TwcK samples; design, prioritize and validate mutated and truncated variants; assess sample stability and perform activity assays. The strategy is exportable to other pseudokinase members of the TK-like kinase family.
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Affiliation(s)
- Julius Bogomolovas
- School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | | | - Olga Mayans
- Department of Biology, University of Konstanz, Konstanz, Germany.
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19
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Novel compound heterozygous mutations in the TTN gene: elongation and truncation variants causing limb-girdle muscular dystrophy type 2J in a Han Chinese family. Neurol Sci 2022; 43:3427-3433. [DOI: 10.1007/s10072-022-05979-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/18/2022] [Indexed: 10/18/2022]
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20
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de Regt AK, Clark CJ, Asbury CL, Biggins S. Tension can directly suppress Aurora B kinase-triggered release of kinetochore-microtubule attachments. Nat Commun 2022; 13:2152. [PMID: 35443757 PMCID: PMC9021268 DOI: 10.1038/s41467-022-29542-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 03/03/2022] [Indexed: 11/09/2022] Open
Abstract
Chromosome segregation requires sister kinetochores to attach microtubules emanating from opposite spindle poles. Proper attachments come under tension and are stabilized, but defective attachments lacking tension are released, giving another chance for correct attachments to form. This error correction process depends on Aurora B kinase, which phosphorylates kinetochores to destabilize their microtubule attachments. However, the mechanism by which Aurora B distinguishes tense versus relaxed kinetochores remains unclear because it is difficult to detect kinase-triggered detachment and to manipulate kinetochore tension in vivo. To address these challenges, we apply an optical trapping-based assay using soluble Aurora B and reconstituted kinetochore-microtubule attachments. Strikingly, the tension on these attachments suppresses their Aurora B-triggered release, suggesting that tension-dependent changes in the conformation of kinetochores can regulate Aurora B activity or its outcome. Our work uncovers the basis for a key mechano-regulatory event that ensures accurate segregation and may inform studies of other mechanically regulated enzymes.
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Affiliation(s)
- Anna K de Regt
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Cordell J Clark
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA.
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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21
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Ferenczy GG, Kellermayer M. Contribution of Hydrophobic Interactions to Protein Mechanical Stability. Comput Struct Biotechnol J 2022; 20:1946-1956. [PMID: 35521554 PMCID: PMC9062142 DOI: 10.1016/j.csbj.2022.04.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 04/07/2022] [Accepted: 04/17/2022] [Indexed: 11/26/2022] Open
Abstract
The role of hydrophobic and polar interactions in providing thermodynamic stability to folded proteins has been intensively studied, but the relative contribution of these interactions to the mechanical stability is less explored. We used steered molecular dynamics simulations with constant-velocity pulling to generate force-extension curves of selected protein domains and monitor hydrophobic surface unravelling upon extension. Hydrophobic contribution was found to vary between one fifth and one third of the total force while the rest of the contribution is attributed primarily to hydrogen bonds. Moreover, hydrophobic force peaks were shifted towards larger protein extensions with respect to the force peaks attributed to hydrogen bonds. The higher importance of hydrogen bonds compared to hydrophobic interactions in providing mechanical resistance is in contrast with the relative importance of the hydrophobic interactions in providing thermodynamic stability of proteins. The different contributions of these interactions to the mechanical stability are explained by the steeper free energy dependence of hydrogen bonds compared to hydrophobic interactions on the relative positions of interacting atoms. Comparative analyses for several protein domains revealed that the variation of hydrophobic forces is modest, while the contribution of hydrogen bonds to the force peaks becomes increasingly important for mechanically resistant protein domains.
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22
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Lamber EP, Guicheney P, Pinotsis N. The role of the M-band myomesin proteins in muscle integrity and cardiac disease. J Biomed Sci 2022; 29:18. [PMID: 35255917 PMCID: PMC8900313 DOI: 10.1186/s12929-022-00801-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/28/2022] [Indexed: 11/30/2022] Open
Abstract
Transversal structural elements in cross-striated muscles, such as the M-band or the Z-disc, anchor and mechanically stabilize the contractile apparatus and its minimal unit—the sarcomere. The ability of proteins to target and interact with these structural sarcomeric elements is an inevitable necessity for the correct assembly and functionality of the myofibrillar apparatus. Specifically, the M-band is a well-recognized mechanical and signaling hub dealing with active forces during contraction, while impairment of its function leads to disease and death. Research on the M-band architecture is focusing on the assembly and interactions of the three major filamentous proteins in the region, mainly the three myomesin proteins including their embryonic heart (EH) isoform, titin and obscurin. These proteins form the basic filamentous network of the M-band, interacting with each other as also with additional proteins in the region that are involved in signaling, energetic or mechanosensitive processes. While myomesin-1, titin and obscurin are found in every muscle, the expression levels of myomesin-2 (also known as M-protein) and myomesin-3 are tissue specific: myomesin-2 is mainly expressed in the cardiac and fast skeletal muscles, while myomesin-3 is mainly expressed in intermediate muscles and specific regions of the cardiac muscle. Furthermore, EH-myomesin apart from its role during embryonic stages, is present in adults with specific cardiac diseases. The current work in structural, molecular, and cellular biology as well as in animal models, provides important details about the assembly of myomesin-1, obscurin and titin, the information however about the myomesin-2 and -3, such as their interactions, localization and structural details remain very limited. Remarkably, an increasing number of reports is linking all three myomesin proteins and particularly myomesin-2 to serious cardiovascular diseases suggesting that this protein family could be more important than originally thought. In this review we will focus on the myomesin protein family, the myomesin interactions and structural differences between isoforms and we will provide the most recent evidence why the structurally and biophysically unexplored myomesin-2 and myomesin-3 are emerging as hot targets for understanding muscle function and disease.
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23
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Daday C, de Buhr S, Mercadante D, Gräter F. Mechanical force can enhance c-Src kinase activity by impairing autoinhibition. Biophys J 2022; 121:684-691. [PMID: 35120901 PMCID: PMC8943751 DOI: 10.1016/j.bpj.2022.01.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/21/2021] [Accepted: 01/28/2022] [Indexed: 11/25/2022] Open
Abstract
Cellular mechanosensing is pivotal for virtually all biological processes, and many molecular mechano-sensors and their way of function are being uncovered. In this work, we suggest that c-Src kinase acts as a direct mechano-sensor. c-Src is responsible for, among others, cell proliferation, and shows increased activity in stretched cells. In its native state, c-Src has little basal activity, because its kinase domain binds to an SH2 and SH3 domain. However, it is known that c-Src can bind to p130Cas, through which force can be transmitted to the membrane. Using molecular dynamics simulations, we show that force acting between the membrane-bound N-terminus of the SH3 domain and p130Cas induces partial SH3 unfolding, thereby impeding rebinding of the kinase domain onto SH2/SH3 and effectively enhancing kinase activity. Forces involved in this process are slightly lower or similar to the forces required to pull out c-Src from the membrane through the myristoyl linker, and key interactions involved in this anchoring are salt bridges between negative lipids and nearby basic residues in c-Src. Thus, c-Src appears to be a candidate for an intriguing mechanosensing mechanism of impaired kinase inhibition, which can be potentially tuned by membrane composition and other environmental factors.
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Affiliation(s)
- Csaba Daday
- Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Svenja de Buhr
- Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | | | - Frauke Gräter
- Heidelberg Institute for Theoretical Studies, Heidelberg, Germany; Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Mathematikon, Heidelberg, Germany.
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24
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Attwaters M, Hughes SM. Cellular and molecular pathways controlling muscle size in response to exercise. FEBS J 2022; 289:1428-1456. [PMID: 33755332 DOI: 10.1111/febs.15820] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/27/2021] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
From the discovery of ATP and motor proteins to synaptic neurotransmitters and growth factor control of cell differentiation, skeletal muscle has provided an extreme model system in which to understand aspects of tissue function. Muscle is one of the few tissues that can undergo both increase and decrease in size during everyday life. Muscle size depends on its contractile activity, but the precise cellular and molecular pathway(s) by which the activity stimulus influences muscle size and strength remain unclear. Four correlates of muscle contraction could, in theory, regulate muscle growth: nerve-derived signals, cytoplasmic calcium dynamics, the rate of ATP consumption and physical force. Here, we summarise the evidence for and against each stimulus and what is known or remains unclear concerning their molecular signal transduction pathways and cellular effects. Skeletal muscle can grow in three ways, by generation of new syncytial fibres, addition of nuclei from muscle stem cells to existing fibres or increase in cytoplasmic volume/nucleus. Evidence suggests the latter two processes contribute to exercise-induced growth. Fibre growth requires increase in sarcolemmal surface area and cytoplasmic volume at different rates. It has long been known that high-force exercise is a particularly effective growth stimulus, but how this stimulus is sensed and drives coordinated growth that is appropriately scaled across organelles remains a mystery.
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Affiliation(s)
- Michael Attwaters
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
| | - Simon M Hughes
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
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25
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Yang T, Park C, Rah SH, Shon MJ. Nano-Precision Tweezers for Mechanosensitive Proteins and Beyond. Mol Cells 2022; 45:16-25. [PMID: 35114644 PMCID: PMC8819490 DOI: 10.14348/molcells.2022.2026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/27/2022] Open
Abstract
Mechanical forces play pivotal roles in regulating cell shape, function, and fate. Key players that govern the mechanobiological interplay are the mechanosensitive proteins found on cell membranes and in cytoskeleton. Their unique nanomechanics can be interrogated using single-molecule tweezers, which can apply controlled forces to the proteins and simultaneously measure the ensuing structural changes. Breakthroughs in high-resolution tweezers have enabled the routine monitoring of nanometer-scale, millisecond dynamics as a function of force. Undoubtedly, the advancement of structural biology will be further fueled by integrating static atomic-resolution structures and their dynamic changes and interactions observed with the force application techniques. In this minireview, we will introduce the general principles of single-molecule tweezers and their recent applications to the studies of force-bearing proteins, including the synaptic proteins that need to be categorized as mechanosensitive in a broad sense. We anticipate that the impact of nano-precision approaches in mechanobiology research will continue to grow in the future.
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Affiliation(s)
- Taehyun Yang
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Celine Park
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sang-Hyun Rah
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Min Ju Shon
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 37673, Korea
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26
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Nanosurgical Manipulation of Titin and Its M-Complex. NANOMATERIALS 2022; 12:nano12020178. [PMID: 35055197 PMCID: PMC8779236 DOI: 10.3390/nano12020178] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 01/21/2023]
Abstract
Titin is a multifunctional filamentous protein anchored in the M-band, a hexagonally organized supramolecular lattice in the middle of the muscle sarcomere. Functionally, the M-band is a framework that cross-links myosin thick filaments, organizes associated proteins, and maintains sarcomeric symmetry via its structural and putative mechanical properties. Part of the M-band appears at the C-terminal end of isolated titin molecules in the form of a globular head, named here the “M-complex”, which also serves as the point of head-to-head attachment of titin. We used high-resolution atomic force microscopy and nanosurgical manipulation to investigate the topographical and internal structure and local mechanical properties of the M-complex and its associated titin molecules. We find that the M-complex is a stable structure that corresponds to the transverse unit of the M-band organized around the myosin thick filament. M-complexes may be interlinked into an M-complex array that reflects the local structural and mechanical status of the transversal M-band lattice. Local segments of titin and the M-complex could be nanosurgically manipulated to achieve extension and domain unfolding. Long threads could be pulled out of the M-complex, suggesting that it is a compact supramolecular reservoir of extensible filaments. Nanosurgery evoked an unexpected volume increment in the M-complex, which may be related to its function as a mechanical spacer. The M-complex thus displays both elastic and plastic properties which support the idea that the M-band may be involved in mechanical functions within the muscle sarcomere.
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27
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Mahdavi M, Mohsen-Pour N, Maleki M, Hesami M, Naderi N, Houshmand G, Rasouli Jazi HR, Shahzadi H, Kalayinia S. Whole-exome sequencing identified compound heterozygous variants in the TTN gene causing Salih myopathy with dilated cardiomyopathy in an Iranian family. Cardiol Young 2021; 32:1-6. [PMID: 34782032 DOI: 10.1017/s1047951121004455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Salih myopathy, characterised by both congenital myopathy and fatal dilated cardiomyopathy, is an inherited muscle disorder that affects skeletal and cardiac muscles. TTN has been identified as the main cause of this myopathy, the enormous size of this gene poses a formidable challenge to molecular genetic diagnostics. METHOD In the present study, whole-exome sequencing, cardiac MRI, and metabolic parameter assessment were performed to investigate the genetic causes of Salih myopathy in a consanguineous Iranian family who presented with titinopathy involving both skeletal and heart muscles in an autosomal recessive inheritance pattern. RESULTS Two missense variants of TTN gene (NM_001267550.2), namely c.61280A>C (p. Gln20427Pro) and c.54970G>A (p. Gly18324Ser), were detected and segregations were confirmed by polymerase chain reaction-based Sanger sequencing. CONCLUSIONS The compound heterozygous variants, c.61280A>C, (p. Gln20427Pro) and c.54970G>A, (p. Gly18324Ser) in the TTN gene appear to be the cause of Salih myopathy and dilated cardiomyopathy in the family presented. Whole-exome sequencing is an effective molecular diagnostic tool to identify the causative genetic variants of large genes such as TTN.
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Affiliation(s)
- Mohammad Mahdavi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Neda Mohsen-Pour
- Zanjan Pharmaceutical Biotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahshid Hesami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Niloofar Naderi
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Golnaz Houshmand
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Hamid R Rasouli Jazi
- Biotechnology Research Center, Malek Ashtar University of Technology, Tehran, Iran
| | - Hossein Shahzadi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
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28
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Gene expression changes in vastus lateralis muscle after different strength training regimes during rehabilitation following anterior cruciate ligament reconstruction. PLoS One 2021; 16:e0258635. [PMID: 34648569 PMCID: PMC8516190 DOI: 10.1371/journal.pone.0258635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 10/03/2021] [Indexed: 11/19/2022] Open
Abstract
Impaired muscle regeneration has repeatedly been described after anterior cruciate ligament reconstruction (ACL-R). The results of recent studies provided some evidence for negative alterations in knee extensor muscles after ACL-R causing persisting strength deficits in spite of the regain of muscle mass. Accordingly, we observed that 12 weeks of concentric/eccentric quadriceps strength training with eccentric overload (CON/ECC+) induced a significantly greater hypertrophy of the atrophied quadriceps muscle after ACL-R than conventional concentric/eccentric quadriceps strength training (CON/ECC). However, strength deficits persisted and there was an unexpected increase in the proportion of slow type I fibers instead of the expected shift towards a faster muscle phenotype after CON/ECC+. In order to shed further light on muscle recovery after ACL-R, the steady-state levels of 84 marker mRNAs were analyzed in biopsies obtained from the vastus lateralis muscle of 31 subjects before and after 12 weeks of CON/ECC+ (n = 18) or CON/ECC strength training (n = 13) during rehabilitation after ACL-R using a custom RT2 Profiler PCR array. Significant (p < 0.05) changes were detected in the expression of 26 mRNAs, several of them involved in muscle wasting/atrophy. A different pattern with regard to the strength training mode was observed for 16 mRNAs, indicating an enhanced hypertrophic stimulus, mechanical sensing or fast contractility after CON/ECC+. The effects of the type of autograft (quadriceps, QUAD, n = 19, or semitendinosus tendon, SEMI, n = 12) were reflected in the lower expression of 6 mRNAs involved in skeletal muscle hypertrophy or contractility in QUAD. In conclusion, the greater hypertrophic stimulus and mechanical stress induced by CON/ECC+ and a beginning shift towards a faster muscle phenotype after CON/ECC+ might be indicated by significant gene expression changes as well as still ongoing muscle wasting processes and a negative impact of QUAD autograft.
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29
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Bogomolovas J, Fleming JR, Franke B, Manso B, Simon B, Gasch A, Markovic M, Brunner T, Knöll R, Chen J, Labeit S, Scheffner M, Peter C, Mayans O. Titin kinase ubiquitination aligns autophagy receptors with mechanical signals in the sarcomere. EMBO Rep 2021; 22:e48018. [PMID: 34402565 PMCID: PMC8490993 DOI: 10.15252/embr.201948018] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/13/2022] Open
Abstract
Striated muscle undergoes remodelling in response to mechanical and physiological stress, but little is known about the integration of such varied signals in the myofibril. The interaction of the elastic kinase region from sarcomeric titin (A168-M1) with the autophagy receptors Nbr1/p62 and MuRF E3 ubiquitin ligases is well suited to link mechanosensing with the trophic response of the myofibril. To investigate the mechanisms of signal cross-talk at this titin node, we elucidated its 3D structure, analysed its response to stretch using steered molecular dynamics simulations and explored its functional relation to MuRF1 and Nbr1/p62 using cellular assays. We found that MuRF1-mediated ubiquitination of titin kinase promotes its scaffolding of Nbr1/p62 and that the process can be dynamically down-regulated by the mechanical unfolding of a linker sequence joining titin kinase with the MuRF1 receptor site in titin. We propose that titin ubiquitination is sensitive to the mechanical state of the sarcomere, the regulation of sarcomere targeting by Nbr1/p62 being a functional outcome. We conclude that MuRF1/Titin Kinase/Nbr1/p62 constitutes a distinct assembly that predictably promotes sarcomere breakdown in inactive muscle.
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Affiliation(s)
- Julius Bogomolovas
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
- Department of Cognitive and Clinical NeuroscienceCentral Institute of Mental HealthMedical Faculty MannheimHeidelberg UniversityMannheimGermany
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Barbara Franke
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bruno Manso
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bernd Simon
- Structural and Computational Biology UnitEMBLHeidelbergGermany
| | - Alexander Gasch
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Thomas Brunner
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Ralph Knöll
- Integrated Cardio Metabolic Centre (ICMC)Heart and Vascular ThemeUniversity Hospital, MedHKarolinska InstitutetHuddingeSweden
- Bioscience, CardiovascularRenal & MetabolismBioPharmaceuticalsR&D, AstraZenecaGothenburgSweden
| | - Ju Chen
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
| | - Siegfried Labeit
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Christine Peter
- Department of ChemistryUniversity of KonstanzKonstanzGermany
| | - Olga Mayans
- Department of BiologyUniversity of KonstanzKonstanzGermany
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30
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Swiatlowska P, Iskratsch T. Tools for studying and modulating (cardiac muscle) cell mechanics and mechanosensing across the scales. Biophys Rev 2021; 13:611-623. [PMID: 34765044 PMCID: PMC8553672 DOI: 10.1007/s12551-021-00837-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/24/2021] [Indexed: 12/26/2022] Open
Abstract
Cardiomyocytes generate force for the contraction of the heart to pump blood into the lungs and body. At the same time, they are exquisitely tuned to the mechanical environment and react to e.g. changes in cell and extracellular matrix stiffness or altered stretching due to reduced ejection fraction in heart disease, by adapting their cytoskeleton, force generation and cell mechanics. Both mechanical sensing and cell mechanical adaptations are multiscale processes. Receptor interactions with the extracellular matrix at the nanoscale will lead to clustering of receptors and modification of the cytoskeleton. This in turn alters mechanosensing, force generation, cell and nuclear stiffness and viscoelasticity at the microscale. Further, this affects cell shape, orientation, maturation and tissue integration at the microscale to macroscale. A variety of tools have been developed and adapted to measure cardiomyocyte receptor-ligand interactions and forces or mechanics at the different ranges, resulting in a wealth of new information about cardiomyocyte mechanobiology. Here, we take stock at the different tools for exploring cardiomyocyte mechanosensing and cell mechanics at the different scales from the nanoscale to microscale and macroscale.
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Affiliation(s)
- Pamela Swiatlowska
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Thomas Iskratsch
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
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31
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Solís C, Russell B. Striated muscle proteins are regulated both by mechanical deformation and by chemical post-translational modification. Biophys Rev 2021; 13:679-695. [PMID: 34777614 PMCID: PMC8555064 DOI: 10.1007/s12551-021-00835-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/23/2021] [Indexed: 01/09/2023] Open
Abstract
All cells sense force and build their cytoskeleton to optimize function. How is this achieved? Two major systems are involved. The first is that load deforms specific protein structures in a proportional and orientation-dependent manner. The second is post-translational modification of proteins as a consequence of signaling pathway activation. These two processes work together in a complex way so that local subcellular assembly as well as overall cell function are controlled. This review discusses many cell types but focuses on striated muscle. Detailed information is provided on how load deforms the structure of proteins in the focal adhesions and filaments, using α-actinin, vinculin, talin, focal adhesion kinase, LIM domain-containing proteins, filamin, myosin, titin, and telethonin as examples. Second messenger signals arising from external triggers are distributed throughout the cell causing post-translational or chemical modifications of protein structures, with the actin capping protein CapZ and troponin as examples. There are numerous unanswered questions of how mechanical and chemical signals are integrated by muscle proteins to regulate sarcomere structure and function yet to be studied. Therefore, more research is needed to see how external triggers are integrated with local tension generated within the cell. Nonetheless, maintenance of tension in the sarcomere is the essential and dominant mechanism, leading to the well-known phrase in exercise physiology: "use it or lose it."
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Affiliation(s)
- Christopher Solís
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Brenda Russell
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612 USA
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32
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Porto D, Matsunaga Y, Franke B, Williams RM, Qadota H, Mayans O, Benian GM, Lu H. Conformational changes in twitchin kinase in vivo revealed by FRET imaging of freely moving C. elegans. eLife 2021; 10:e66862. [PMID: 34569929 PMCID: PMC8523150 DOI: 10.7554/elife.66862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 09/24/2021] [Indexed: 02/07/2023] Open
Abstract
The force-induced unfolding and refolding of proteins is speculated to be a key mechanism in the sensing and transduction of mechanical signals in the living cell. Yet, little evidence has been gathered for its existence in vivo. Prominently, stretch-induced unfolding is postulated to be the activation mechanism of the twitchin/titin family of autoinhibited sarcomeric kinases linked to the mechanical stress response of muscle. To test the occurrence of mechanical kinase activation in living working muscle, we generated transgenic Caenorhabditis elegans expressing twitchin containing FRET moieties flanking the kinase domain and developed a quantitative technique for extracting FRET signals in freely moving C. elegans, using tracking and simultaneous imaging of animals in three channels (donor fluorescence, acceptor fluorescence, and transmitted light). Computer vision algorithms were used to extract fluorescence signals and muscle contraction states in each frame, in order to obtain fluorescence and body curvature measurements with spatial and temporal precision in vivo. The data revealed statistically significant periodic changes in FRET signals during muscle activity, consistent with a periodic change in the conformation of twitchin kinase. We conclude that stretch-unfolding of twitchin kinase occurs in the active muscle, whereby mechanical activity titrates the signaling pathway of this cytoskeletal kinase. We anticipate that the methods we have developed here could be applied to obtaining in vivo evidence for force-induced conformational changes or elastic behavior of other proteins not only in C. elegans but in other animals in which there is optical transparency (e.g., zebrafish).
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Affiliation(s)
- Daniel Porto
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
| | - Yohei Matsunaga
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Barbara Franke
- Department of Biology, University of KonstanzKonstanzGermany
| | - Rhys M Williams
- Department of Biology, University of KonstanzKonstanzGermany
| | - Hiroshi Qadota
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Olga Mayans
- Department of Biology, University of KonstanzKonstanzGermany
| | - Guy M Benian
- Department of Pathology, Emory UniversityAtlantaUnited States
| | - Hang Lu
- Interdisciplinary Bioengineering Program, Georgia Institute of TechnologyAtlantaUnited States
- School of Chemical & Biomolecular Engineering, Georgia Institute of TechnologyAtlantaUnited States
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33
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Biquand A, Spinozzi S, Tonino P, Cosette J, Strom J, Elbeck Z, Knöll R, Granzier H, Lostal W, Richard I. Titin M-line insertion sequence 7 is required for proper cardiac function in mice. J Cell Sci 2021; 134:271843. [PMID: 34401916 DOI: 10.1242/jcs.258684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/06/2021] [Indexed: 11/20/2022] Open
Abstract
Titin is a giant sarcomeric protein that is involved in a large number of functions, with a primary role in skeletal and cardiac sarcomere organization and stiffness. The titin gene (TTN) is subject to various alternative splicing events, but in the region that is present at the M-line, the only exon that can be spliced out is Mex5, which encodes for the insertion sequence 7 (is7). Interestingly, in the heart, the majority of titin isoforms are Mex5+, suggesting a cardiac role for is7. Here, we performed comprehensive functional, histological, transcriptomic, microscopic and molecular analyses of a mouse model lacking the Ttn Mex5 exon (ΔMex5), and revealed that the absence of the is7 is causative for dilated cardiomyopathy. ΔMex5 mice showed altered cardiac function accompanied by increased fibrosis and ultrastructural alterations. Abnormal expression of excitation-contraction coupling proteins was also observed. The results reported here confirm the importance of the C-terminal region of titin in cardiac function and are the first to suggest a possible relationship between the is7 and excitation-contraction coupling. Finally, these findings give important insights for the identification of new targets in the treatment of titinopathies.
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Affiliation(s)
- Ariane Biquand
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Simone Spinozzi
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Paola Tonino
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | | | - Joshua Strom
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Zaher Elbeck
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Ralph Knöll
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institutet, 141 57 Huddinge, Sweden.,Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, 431 50 Gothenburg, Sweden
| | - Henk Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - William Lostal
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
| | - Isabelle Richard
- Genethon, 91000 Evry, France.,Université Paris-Saclay, Univ Evry, Inserm, Généthon, Integrare research unit UMR_S951, 91000 Evry-Courcouronnes, France
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34
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Why exercise builds muscles: titin mechanosensing controls skeletal muscle growth under load. Biophys J 2021; 120:3649-3663. [PMID: 34389312 PMCID: PMC8456289 DOI: 10.1016/j.bpj.2021.07.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/29/2021] [Accepted: 07/23/2021] [Indexed: 12/22/2022] Open
Abstract
Muscles sense internally generated and externally applied forces, responding to these in a coordinated hierarchical manner at different timescales. The center of the basic unit of the muscle, the sarcomeric M-band, is perfectly placed to sense the different types of load to which the muscle is subjected. In particular, the kinase domain of titin (TK) located at the M-band is a known candidate for mechanical signaling. Here, we develop a quantitative mathematical model that describes the kinetics of TK-based mechanosensitive signaling and predicts trophic changes in response to exercise and rehabilitation regimes. First, we build the kinetic model for TK conformational changes under force: opening, phosphorylation, signaling, and autoinhibition. We find that TK opens as a metastable mechanosensitive switch, which naturally produces a much greater signal after high-load resistance exercise than an equally energetically costly endurance effort. Next, for the model to be stable and give coherent predictions, in particular for the lag after the onset of an exercise regime, we have to account for the associated kinetics of phosphate (carried by ATP) and for the nonlinear dependence of protein synthesis rates on muscle fiber size. We suggest that the latter effect may occur via the steric inhibition of ribosome diffusion through the sieve-like myofilament lattice. The full model yields a steady-state solution (homeostasis) for muscle cross-sectional area and tension and, a quantitatively plausible hypertrophic response to training, as well as atrophy after an extended reduction in tension.
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35
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Alegre-Cebollada J. Protein nanomechanics in biological context. Biophys Rev 2021; 13:435-454. [PMID: 34466164 PMCID: PMC8355295 DOI: 10.1007/s12551-021-00822-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022] Open
Abstract
How proteins respond to pulling forces, or protein nanomechanics, is a key contributor to the form and function of biological systems. Indeed, the conventional view that proteins are able to diffuse in solution does not apply to the many polypeptides that are anchored to rigid supramolecular structures. These tethered proteins typically have important mechanical roles that enable cells to generate, sense, and transduce mechanical forces. To fully comprehend the interplay between mechanical forces and biology, we must understand how protein nanomechanics emerge in living matter. This endeavor is definitely challenging and only recently has it started to appear tractable. Here, I introduce the main in vitro single-molecule biophysics methods that have been instrumental to investigate protein nanomechanics over the last 2 decades. Then, I present the contemporary view on how mechanical force shapes the free energy of tethered proteins, as well as the effect of biological factors such as post-translational modifications and mutations. To illustrate the contribution of protein nanomechanics to biological function, I review current knowledge on the mechanobiology of selected muscle and cell adhesion proteins including titin, talin, and bacterial pilins. Finally, I discuss emerging methods to modulate protein nanomechanics in living matter, for instance by inducing specific mechanical loss-of-function (mLOF). By interrogating biological systems in a causative manner, these new tools can contribute to further place protein nanomechanics in a biological context.
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36
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Maksudov F, Jones LK, Barsegov V. Statistical Learning from Single-Molecule Experiments: Support Vector Machines and Expectation-Maximization Approaches to Understanding Protein Unfolding Data. J Phys Chem B 2021; 125:5794-5808. [PMID: 34075752 DOI: 10.1021/acs.jpcb.1c02334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Single-molecule force spectroscopy has become a powerful tool for the exploration of dynamic processes that involve proteins; yet, meaningful interpretation of the experimental data remains challenging. Owing to low signal-to-noise ratio, experimental force-extension spectra contain force signals due to nonspecific interactions, tip or substrate detachment, and protein desorption. Unravelling of complex protein structures results in the unfolding transitions of different types. Here, we test the performance of Support Vector Machines (SVM) and Expectation Maximization (EM) approaches in statistical learning from dynamic force experiments. When the output from molecular modeling in silico (or other studies) is used as a training set, SVM and EM can be applied to understand the unfolding force data. The maximal margin or maximum likelihood classifier can be used to separate experimental test observations into the unfolding transitions of different types, and EM optimization can then be utilized to resolve the statistics of unfolding forces: weights, average forces, and standard deviations. We designed an EM-based approach, which can be directly applied to the experimental data without data classification and division into training and test observations. This approach performs well even when the sample size is small and when the unfolding transitions are characterized by overlapping force ranges.
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37
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Shenkman BS, Tsaturyan AK, Vikhlyantsev IM, Kozlovskaya IB, Grigoriev AI. Molecular Mechanisms of Muscle Tone Impairment under Conditions of Real and Simulated Space Flight. Acta Naturae 2021; 13:85-97. [PMID: 34377559 PMCID: PMC8327152 DOI: 10.32607/actanaturae.10953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/04/2020] [Indexed: 01/08/2023] Open
Abstract
Kozlovskaya et al. [1] and Grigoriev et al. [2] showed that enormous loss of muscle stiffness (atonia) develops in humans under true (space flight) and simulated microgravity conditions as early as after the first days of exposure. This phenomenon is attributed to the inactivation of slow motor units and called reflectory atonia. However, a lot of evidence indicating that even isolated muscle or a single fiber possesses substantial stiffness was published at the end of the 20th century. This intrinsic stiffness is determined by the active component, i.e. the ability to form actin-myosin cross-bridges during muscle stretch and contraction, as well as by cytoskeletal and extracellular matrix proteins, capable of resisting muscle stretch. The main facts on intrinsic muscle stiffness under conditions of gravitational unloading are considered in this review. The data obtained in studies of humans under dry immersion and rodent hindlimb suspension is analyzed. The results and hypotheses regarding reduced probability of cross-bridge formation in an atrophying muscle due to increased interfilament spacing are described. The evidence of cytoskeletal protein (titin, nebulin, etc.) degradation during gravitational unloading is also discussed. The possible mechanisms underlying structural changes in skeletal muscle collagen and its role in reducing intrinsic muscle stiffness are presented. The molecular mechanisms of changes in intrinsic stiffness during space flight and simulated microgravity are reviewed.
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Affiliation(s)
- B. S. Shenkman
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
| | - A. K. Tsaturyan
- Lomonosov Moscow State University Research Institute of Mechanics, Moscow, 119192 Russia
| | - I. M. Vikhlyantsev
- Institute of Experimental and Theoretical Biophysics, Moscow Region, Pushchino, 142290 Russia
| | - I. B. Kozlovskaya
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
| | - A. I. Grigoriev
- State Scientific Center of Russian Federation – Institute of Biomedical Problems, Moscow, 123007 Russia
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38
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Shinde A, Illath K, Gupta P, Shinde P, Lim KT, Nagai M, Santra TS. A Review of Single-Cell Adhesion Force Kinetics and Applications. Cells 2021; 10:577. [PMID: 33808043 PMCID: PMC8000588 DOI: 10.3390/cells10030577] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
Cells exert, sense, and respond to the different physical forces through diverse mechanisms and translating them into biochemical signals. The adhesion of cells is crucial in various developmental functions, such as to maintain tissue morphogenesis and homeostasis and activate critical signaling pathways regulating survival, migration, gene expression, and differentiation. More importantly, any mutations of adhesion receptors can lead to developmental disorders and diseases. Thus, it is essential to understand the regulation of cell adhesion during development and its contribution to various conditions with the help of quantitative methods. The techniques involved in offering different functionalities such as surface imaging to detect forces present at the cell-matrix and deliver quantitative parameters will help characterize the changes for various diseases. Here, we have briefly reviewed single-cell mechanical properties for mechanotransduction studies using standard and recently developed techniques. This is used to functionalize from the measurement of cellular deformability to the quantification of the interaction forces generated by a cell and exerted on its surroundings at single-cell with attachment and detachment events. The adhesive force measurement for single-cell microorganisms and single-molecules is emphasized as well. This focused review should be useful in laying out experiments which would bring the method to a broader range of research in the future.
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Affiliation(s)
- Ashwini Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Kavitha Illath
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Gupta
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Pallavi Shinde
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
| | - Ki-Taek Lim
- Department of Biosystems Engineering, Kangwon National University, Chuncheon-Si, Gangwon-Do 24341, Korea;
| | - Moeto Nagai
- Department of Mechanical Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan;
| | - Tuhin Subhra Santra
- Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India; (A.S.); (K.I.); (P.G.); (P.S.)
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39
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Jiang H, Hooper C, Kelly M, Steeples V, Simon JN, Beglov J, Azad AJ, Leinhos L, Bennett P, Ehler E, Kalisch-Smith JI, Sparrow DB, Fischer R, Heilig R, Isackson H, Ehsan M, Patone G, Huebner N, Davies B, Watkins H, Gehmlich K. Functional analysis of a gene-edited mouse model to gain insights into the disease mechanisms of a titin missense variant. Basic Res Cardiol 2021; 116:14. [PMID: 33637999 PMCID: PMC7910237 DOI: 10.1007/s00395-021-00853-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/10/2021] [Indexed: 11/03/2022]
Abstract
Titin truncating variants are a well-established cause of cardiomyopathy; however, the role of titin missense variants is less well understood. Here we describe the generation of a mouse model to investigate the underlying disease mechanism of a previously reported titin A178D missense variant identified in a family with non-compaction and dilated cardiomyopathy. Heterozygous and homozygous mice carrying the titin A178D missense variant were characterised in vivo by echocardiography. Heterozygous mice had no detectable phenotype at any time point investigated (up to 1 year). By contrast, homozygous mice developed dilated cardiomyopathy from 3 months. Chronic adrenergic stimulation aggravated the phenotype. Targeted transcript profiling revealed induction of the foetal gene programme and hypertrophic signalling pathways in homozygous mice, and these were confirmed at the protein level. Unsupervised proteomics identified downregulation of telethonin and four-and-a-half LIM domain 2, as well as the upregulation of heat shock proteins and myeloid leukaemia factor 1. Loss of telethonin from the cardiac Z-disc was accompanied by proteasomal degradation; however, unfolded telethonin accumulated in the cytoplasm, leading to a proteo-toxic response in the mice.We show that the titin A178D missense variant is pathogenic in homozygous mice, resulting in cardiomyopathy. We also provide evidence of the disease mechanism: because the titin A178D variant abolishes binding of telethonin, this leads to its abnormal cytoplasmic accumulation. Subsequent degradation of telethonin by the proteasome results in proteasomal overload, and activation of a proteo-toxic response. The latter appears to be a driving factor for the cardiomyopathy observed in the mouse model.
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Affiliation(s)
- He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Charlotte Hooper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Matthew Kelly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Julia Beglov
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Amar J Azad
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Lisa Leinhos
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Pauline Bennett
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | | | - Duncan B Sparrow
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Roman Fischer
- Nuffield Department of Clinical Medicine, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Raphael Heilig
- Nuffield Department of Clinical Medicine, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Henrik Isackson
- Department of Medical Sciences, Cardiology, Uppsala University, Uppsala, Sweden
- Department of Medical Cell Biology, Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Giannino Patone
- Max Delbrueck Centre for Molecular Medicine, Berlin, Germany
| | - Norbert Huebner
- Max Delbrueck Centre for Molecular Medicine, Berlin, Germany
| | - Benjamin Davies
- Transgenic Core, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK.
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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40
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Yu J, Cai P, Chen X. Structural Regulation of Myocytes in Engineered Healthy and Diseased Cardiac Models. ACS APPLIED BIO MATERIALS 2021; 4:267-276. [DOI: 10.1021/acsabm.0c01270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jing Yu
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Pingqiang Cai
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Xiaodong Chen
- Innovative Center for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
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41
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Mateti S, Mathesh M, Liu Z, Tao T, Ramireddy T, Glushenkov AM, Yang W, Chen YI. Mechanochemistry: A force in disguise and conditional effects towards chemical reactions. Chem Commun (Camb) 2021; 57:1080-1092. [PMID: 33438694 DOI: 10.1039/d0cc06581a] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mechanochemistry refers to unusual chemical reactions induced by mechanical energy at room temperatures. It has attracted increased attention because of advantages, such as being a solution-free, energy saving, high-productivity and low-temperature process. However, there is limited understanding of the mechanochemical process because mechanochemistry is often conducted using closed milling devices, which are often regarded as a black box. This feature article shows that mechanochemical reactions can be controlled by varying milling parameters, such as the mechanical force, milling intensity, time and atmosphere. New nanomaterials with doped and functionalized structures can be produced under controlled conditions, which provide a critical insight for understanding mechanochemistry. A fundamental mechanism investigation using force microscopy is discussed.
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Affiliation(s)
- Srikanth Mateti
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Vic 3216, Australia.
| | - Motilal Mathesh
- School of Life and Environmental Science, Deakin University, Geelong, Victoria 3216, Australia.
| | - Zhen Liu
- College of Materials Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, 308 Ningxia Road, Qingdao 266071, P. R. China
| | - Tao Tao
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Thrinathreddy Ramireddy
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Alexey M Glushenkov
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Wenrong Yang
- School of Life and Environmental Science, Deakin University, Geelong, Victoria 3216, Australia.
| | - Ying Ian Chen
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Vic 3216, Australia.
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42
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Rindom E, Herskind J, Blaauw B, Overgaard K, Vissing K, Paoli FV. Concomitant excitation and tension development are required for myocellular gene expression and protein synthesis in rat skeletal muscle. Acta Physiol (Oxf) 2021; 231:e13540. [PMID: 32687678 DOI: 10.1111/apha.13540] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 07/12/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
AIM Loading-induced tension development is often assumed to constitute an independent cue to initiate muscle protein synthesis following resistance exercise. However, with traditional physiological models of resistance exercise, changes in loading-induced tension development also reflect changes in neural activation patterns, and direct evidence for a mechanosensitive mechanism is therefore limited. Here, we sought to examine the importance of excitation and tension development per se on initiation of signalling, gene transcription and protein synthesis in rat skeletal muscle. METHODS Isolated rat extensor digitorum longus muscles were allocated to the following interventions: (a) Excitation-induced eccentric contractions (ECC); (b) Passive stretching without excitation (PAS); (c) Excitation with inhibition of contractions (STIM + IMA ) and; (d) Excitation in combination with both inhibition of contractions and PAS (STIM + IMA + PAS). Assessment of transcriptional and translational signalling, gene transcription and acute muscle protein synthesis was compared in stimulated vs contra-lateral non-stimulated control muscle. RESULTS Protein synthesis increased solely in muscles subjected to a combination of excitation and tension development (ECC and STIM + IMA + PAS). The same pattern was true for p38 mitogen-activated protein kinase signalling for gene transcription as well as for gene transcription of immediate early genes FOS and JUN. In contrast, mechanistic target of rapamycin Complex 1 signalling for translation initiation increased in all muscles subjected to increased tension development (ECC and STIM + IMA + PAS as well as PAS). CONCLUSIONS The current study suggests that exercise-induced increases in protein synthesis as well as transcriptional signalling is dependent on the concomitant effect of excitation and tension development, whereas signalling for translation initiation is only dependent of tension development per se.
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Affiliation(s)
- Emil Rindom
- Department of Biomedicine Aarhus University Aarhus Denmark
| | - Jon Herskind
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Bert Blaauw
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Kristian Overgaard
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Kristian Vissing
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Frank V. Paoli
- Department of Biomedicine Aarhus University Aarhus Denmark
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43
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Ding Y, Apostolidou D, Marszalek P. Mechanical Stability of a Small, Highly-Luminescent Engineered Protein NanoLuc. Int J Mol Sci 2020; 22:E55. [PMID: 33374567 PMCID: PMC7801952 DOI: 10.3390/ijms22010055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/19/2020] [Accepted: 12/20/2020] [Indexed: 11/16/2022] Open
Abstract
NanoLuc is a bioluminescent protein recently engineered for applications in molecular imaging and cellular reporter assays. Compared to other bioluminescent proteins used for these applications, like Firefly Luciferase and Renilla Luciferase, it is ~150 times brighter, more thermally stable, and smaller. Yet, no information is known with regards to its mechanical properties, which could introduce a new set of applications for this unique protein, such as a novel biomaterial or as a substrate for protein activity/refolding assays. Here, we generated a synthetic NanoLuc derivative protein that consists of three connected NanoLuc proteins flanked by two human titin I91 domains on each side and present our mechanical studies at the single molecule level by performing Single Molecule Force Spectroscopy (SMFS) measurements. Our results show each NanoLuc repeat in the derivative behaves as a single domain protein, with a single unfolding event occurring on average when approximately 72 pN is applied to the protein. Additionally, we performed cyclic measurements, where the forces applied to a single protein were cyclically raised then lowered to allow the protein the opportunity to refold: we observed the protein was able to refold to its correct structure after mechanical denaturation only 16.9% of the time, while another 26.9% of the time there was evidence of protein misfolding to a potentially non-functional conformation. These results show that NanoLuc is a mechanically moderately weak protein that is unable to robustly refold itself correctly when stretch-denatured, which makes it an attractive model for future protein folding and misfolding studies.
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Affiliation(s)
- Yue Ding
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA; (Y.D.); (D.A.)
- Department of Engineering Mechanics, SVL, Xi’an Jiaotong University, Xi’an 710049, China
| | - Dimitra Apostolidou
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA; (Y.D.); (D.A.)
| | - Piotr Marszalek
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA; (Y.D.); (D.A.)
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44
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Campbell H, Aguilar-Sanchez Y, Quick AP, Dobrev D, Wehrens XHT. SPEG: a key regulator of cardiac calcium homeostasis. Cardiovasc Res 2020; 117:2175-2185. [PMID: 33067609 DOI: 10.1093/cvr/cvaa290] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/15/2020] [Accepted: 10/02/2020] [Indexed: 12/27/2022] Open
Abstract
Proper cardiac Ca2+ homeostasis is essential for normal excitation-contraction coupling. Perturbations in cardiac Ca2+ handling through altered kinase activity has been implicated in altered cardiac contractility and arrhythmogenesis. Thus, a better understanding of cardiac Ca2+ handling regulation is vital for a better understanding of various human disease processes. 'Striated muscle preferentially expressed protein kinase' (SPEG) is a member of the myosin light chain kinase family that is key for normal cardiac function. Work within the last 5 years has revealed that SPEG has a crucial role in maintaining normal cardiac Ca2+ handling through maintenance of transverse tubule formation and phosphorylation of junctional membrane complex proteins. Additionally, SPEG has been causally impacted in human genetic diseases such as centronuclear myopathy and dilated cardiomyopathy as well as in common acquired cardiovascular disease such as heart failure and atrial fibrillation. Given the rapidly emerging role of SPEG as a key cardiac Ca2+ regulator, we here present this review in order to summarize recent findings regarding the mechanisms of SPEG regulation of cardiac excitation-contraction coupling in both physiology and human disease. A better understanding of the roles of SPEG will be important for a more complete comprehension of cardiac Ca2+ regulation in physiology and disease.
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Affiliation(s)
- Hannah Campbell
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.,Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuriana Aguilar-Sanchez
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ann P Quick
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dobromir Dobrev
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.,Institute of Pharmacology, University Duisburg-Essen, Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX 77030, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.,Center for Space Medicine, Baylor College of Medicine, Houston, TX 77030, USA
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45
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Diurnal Differences in Human Muscle Isometric Force In Vivo Are Associated with Differential Phosphorylation of Sarcomeric M-Band Proteins. Proteomes 2020; 8:proteomes8030022. [PMID: 32859009 PMCID: PMC7565642 DOI: 10.3390/proteomes8030022] [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: 06/29/2020] [Revised: 08/06/2020] [Accepted: 08/25/2020] [Indexed: 12/25/2022] Open
Abstract
We investigated whether diurnal differences in muscle force output are associated with the post-translational state of muscle proteins. Ten physically active men (mean ± SD; age 26.7 ± 3.7 y) performed experimental sessions in the morning (08:00 h) and evening (17:00 h), which were counterbalanced in order of administration and separated by at least 72 h. Knee extensor maximal voluntary isometric contraction (MVIC) force and peak rate of force development (RFD) were measured, and samples of vastus lateralis were collected immediately after exercise. MVIC force was greater in the evening (mean difference of 67 N, 10.2%; p < 0.05). Two-dimensional (2D) gel analysis encompassed 122 proteoforms and discovered 6 significant (p < 0.05; false discovery rate [FDR] = 10%) diurnal differences. Phosphopeptide analysis identified 1693 phosphopeptides and detected 140 phosphopeptides from 104 proteins that were more (p < 0.05, FDR = 22%) phosphorylated in the morning. Myomesin 2, muscle creatine kinase, and the C-terminus of titin exhibited the most robust (FDR < 10%) diurnal differences. Exercise in the morning, compared to the evening, coincided with a greater phosphorylation of M-band-associated proteins in human muscle. These protein modifications may alter the M-band structure and disrupt force transmission, thus potentially explaining the lower force output in the morning.
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46
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Sharma S, Subramani S, Popa I. Does protein unfolding play a functional role in vivo? FEBS J 2020; 288:1742-1758. [PMID: 32761965 DOI: 10.1111/febs.15508] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 12/21/2022]
Abstract
Unfolding and refolding of multidomain proteins under force have yet to be recognized as a major mechanism of function for proteins in vivo. In this review, we discuss the inherent properties of multidomain proteins under a force vector from a structural and functional perspective. We then characterize three main systems where multidomain proteins could play major roles through mechanical unfolding: muscular contraction, cellular mechanotransduction, and bacterial adhesion. We analyze how key multidomain proteins for each system can produce a gain-of-function from the perspective of a fine-tuned quantized response, a molecular battery, delivery of mechanical work through refolding, elasticity tuning, protection and exposure of cryptic sites, and binding-induced mechanical changes. Understanding how mechanical unfolding and refolding affect function will have important implications in designing mechano-active drugs against conditions such as muscular dystrophy, cancer, or novel antibiotics.
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Affiliation(s)
- Sabita Sharma
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Smrithika Subramani
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Ionel Popa
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
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47
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Grogan A, Tsakiroglou P, Kontrogianni-Konstantopoulos A. Double the trouble: giant proteins with dual kinase activity in the heart. Biophys Rev 2020; 12:1019-1029. [PMID: 32638332 DOI: 10.1007/s12551-020-00715-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
Obscurin and its homolog, striated muscle preferentially expressed gene (SPEG), constitute a unique group of proteins abundantly expressed in striated muscles that contain two tandemly arranged MLCK-like kinases. The physiological significance of the dual kinase motifs is largely understudied; however, a collection of recent studies characterizing their binding interactions, putative targets, and disease-linked mutations have begun to shed light on their potential roles in muscle pathophysiology. Specifically, obscurin kinase 1 is proposed to regulate cardiomyocyte adhesion via phosphorylating N-cadherin, whereas SPEG kinases 1 and 2 regulate Ca2+ cycling by phosphorylating junctophilin-2 and the sarcoendoplasmic Ca2+ ATPase 2 (SERCA2). Herein, we review what is currently known regarding the potential substrates, physiological roles, and disease associations of obscurin and SPEG tandem kinase domains and provide future directions that have yet to be investigated.
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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
| | - Panagiotis Tsakiroglou
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St, Baltimore, MD, 21201, USA
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48
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Yang B, Liu Z, Liu H, Nash MA. Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes. Front Mol Biosci 2020; 7:85. [PMID: 32509800 PMCID: PMC7248566 DOI: 10.3389/fmolb.2020.00085] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.
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Affiliation(s)
- Byeongseon Yang
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Zhaowei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Haipei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Michael A. Nash
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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49
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Lepley LK, Davi SM, Hunt ER, Burland JP, White MS, McCormick GY, Butterfield TA. Morphology and Anabolic Response of Skeletal Muscles Subjected to Eccentrically or Concentrically Biased Exercise. J Athl Train 2020; 55:336-342. [PMID: 32196379 DOI: 10.4085/1062-6050-174-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT Long-term eccentric exercise is known to promote muscle growth better than concentric exercise, but its acute effect on muscle is not well understood because of misinterpreted modeling and in situ and in vitro stretch protocols. Knowing if the initial bout of eccentric exercise promotes muscle growth and limits damage is critical to understanding the effect of this mode of exercise. OBJECTIVE To directly evaluate the immediate effects of eccentric and concentric exercises on untrained muscle when fiber strains were physiological and exercise doses were comparable. DESIGN Controlled laboratory study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 40 skeletally mature male Long-Evans rats (age = 16 weeks, mass = 452.1 ± 35.2 g) were randomly assigned to an eccentric exercise (downhill walking, n = 16), concentric exercise (uphill walking, n = 16), or control (no exercise, n = 8) group. INTERVENTION(S) Rats were exposed to a single 15-minute bout of eccentric or concentric exercise on a motorized treadmill and then were euthanized at 6 or 24 hours postexercise. We harvested the vastus lateralis muscle bilaterally. MAIN OUTCOME MEASURE(S) The percentage increase or decrease in protein abundance in exercised animals relative to that in unexercised control animals was evaluated as elevated phosphorylated p70S6k relative to total p70S6k. Fiber damage was quantified using immunoglobulin G permeability staining. One-way analysis of variance and post hoc Tukey tests were performed. RESULTS Rats exposed to eccentric exercise and euthanized at 24 hours had higher percentage response protein synthesis rates than rats exposed to eccentric exercise and euthanized at 6 hours (P = .02) or to concentric exercise and euthanized at 6 (P = .03) or 24 (P = .03) hours. We assessed 9446 fibers for damage and found only 1 fiber was infiltrated (in the concentric exercise group euthanized at 6 hours). Furthermore, no between-groups differences in immunoglobulin G fluorescent intensity were detected (P = .94). CONCLUSIONS Incorporating eccentric exercise is a simple, universally available therapeutic intervention for promoting muscle recovery. A single 15-minute dose of eccentric exercise to a novice muscle can better exert an anabolic effect than a comparable dose of concentric exercise, with very limited evidence of fiber damage.
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Affiliation(s)
| | - Steven M Davi
- Department of Kinesiology, University of Connecticut, Storrs
| | - Emily R Hunt
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
| | - Julie P Burland
- Spaulding National Running Center, Harvard Medical School, Boston, MA
| | | | | | - Timothy A Butterfield
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
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50
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Echarri A, Pavón DM, Sánchez S, García-García M, Calvo E, Huerta-López C, Velázquez-Carreras D, Viaris de Lesegno C, Ariotti N, Lázaro-Carrillo A, Strippoli R, De Sancho D, Alegre-Cebollada J, Lamaze C, Parton RG, Del Pozo MA. An Abl-FBP17 mechanosensing system couples local plasma membrane curvature and stress fiber remodeling during mechanoadaptation. Nat Commun 2019; 10:5828. [PMID: 31862885 PMCID: PMC6925243 DOI: 10.1038/s41467-019-13782-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/22/2019] [Indexed: 12/19/2022] Open
Abstract
Cells remodel their structure in response to mechanical strain. However, how mechanical forces are translated into biochemical signals that coordinate the structural changes observed at the plasma membrane (PM) and the underlying cytoskeleton during mechanoadaptation is unclear. Here, we show that PM mechanoadaptation is controlled by a tension-sensing pathway composed of c-Abl tyrosine kinase and membrane curvature regulator FBP17. FBP17 is recruited to caveolae to induce the formation of caveolar rosettes. FBP17 deficient cells have reduced rosette density, lack PM tension buffering capacity under osmotic shock, and cannot adapt to mechanical strain. Mechanistically, tension is transduced to the FBP17 F-BAR domain by direct phosphorylation mediated by c-Abl, a mechanosensitive molecule. This modification inhibits FBP17 membrane bending activity and releases FBP17-controlled inhibition of mDia1-dependent stress fibers, favoring membrane adaptation to increased tension. This mechanoprotective mechanism adapts the cell to changes in mechanical tension by coupling PM and actin cytoskeleton remodeling. Mechanical forces are sensed by cells and can alter plasma membrane properties, but biochemical changes underlying this are not clear. Here the authors show tension is sensed by c-Abl and FBP17, which couples changes in mechanical tension to remodelling of the plasma membrane and actin cytoskeleton.
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Affiliation(s)
- Asier Echarri
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.
| | - Dácil M Pavón
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Sara Sánchez
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - María García-García
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Enrique Calvo
- Proteomics Unit, Vascular Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Carla Huerta-López
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Diana Velázquez-Carreras
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Christine Viaris de Lesegno
- Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, Institut Curie - Centre de Recherche, PSL Research University, CNRS UMR3666, INSERM U1143, 75248, Paris, France
| | - Nicholas Ariotti
- The Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ana Lázaro-Carrillo
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.,Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | | | - David De Sancho
- Departamento de Ciencia y Tecnología de Polímeros, Euskal Herriko Unibertsitatea, 20018, Donostia-San Sebastián, Spain.,Donostia International Physics Center, Manuel Lardizabal Ibilbidea, 4, 20018, Donostia-San Sebastián, Spain
| | - Jorge Alegre-Cebollada
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Christophe Lamaze
- Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, Institut Curie - Centre de Recherche, PSL Research University, CNRS UMR3666, INSERM U1143, 75248, Paris, France
| | - Robert G Parton
- The Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,The Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Miguel A Del Pozo
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.
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