1
|
Vien KM, Duan Q, Yeung C, Barish S, Volkan PC. Atypical cadherin, Fat2, regulates axon terminal organization in the developing Drosophila olfactory receptor neurons. iScience 2024; 27:110340. [PMID: 39055932 PMCID: PMC11269957 DOI: 10.1016/j.isci.2024.110340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/08/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
The process of how neuronal identity confers circuit organization is intricately related to the mechanisms underlying neurodegeneration and neuropathologies. Modeling this process, the olfactory circuit builds a functionally organized topographic map, which requires widely dispersed neurons with the same identity to converge their axons into one a class-specific neuropil, a glomerulus. In this article, we identified Fat2 (also known as Kugelei) as a regulator of class-specific axon organization. In fat2 mutants, axons belonging to the highest fat2-expressing classes present with a more severe phenotype compared to axons belonging to low fat2-expressing classes. In extreme cases, mutations lead to neural degeneration. Lastly, we found that Fat2 intracellular domain interactors, APC1/2 (Adenomatous polyposis coli) and dop (Drop out), likely orchestrate the cytoskeletal remodeling required for axon condensation. Altogether, we provide a potential mechanism for how cell surface proteins' regulation of cytoskeletal remodeling necessitates identity specific circuit organization.
Collapse
Affiliation(s)
- Khanh M. Vien
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Qichen Duan
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Chun Yeung
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Scott Barish
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Pelin Cayirlioglu Volkan
- Department of Biology, Duke University, Durham, NC 27708, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
2
|
Farkas D, Szikora S, Jijumon AS, Polgár TF, Patai R, Tóth MÁ, Bugyi B, Gajdos T, Bíró P, Novák T, Erdélyi M, Mihály J. Peripheral thickening of the sarcomeres and pointed end elongation of the thin filaments are both promoted by SALS and its formin interaction partners. PLoS Genet 2024; 20:e1011117. [PMID: 38198522 PMCID: PMC10805286 DOI: 10.1371/journal.pgen.1011117] [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: 06/24/2023] [Revised: 01/23/2024] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
During striated muscle development the first periodically repeated units appear in the premyofibrils, consisting of immature sarcomeres that must undergo a substantial growth both in length and width, to reach their final size. Here we report that, beyond its well established role in sarcomere elongation, the Sarcomere length short (SALS) protein is involved in Z-disc formation and peripheral growth of the sarcomeres. Our protein localization data and loss-of-function studies in the Drosophila indirect flight muscle strongly suggest that radial growth of the sarcomeres is initiated at the Z-disc. As to thin filament elongation, we used a powerful nanoscopy approach to reveal that SALS is subject to a major conformational change during sarcomere development, which might be critical to stop pointed end elongation in the adult muscles. In addition, we demonstrate that the roles of SALS in sarcomere elongation and radial growth are both dependent on formin type of actin assembly factors. Unexpectedly, when SALS is present in excess amounts, it promotes the formation of actin aggregates highly resembling the ones described in nemaline myopathy patients. Collectively, these findings helped to shed light on the complex mechanisms of SALS during the coordinated elongation and thickening of the sarcomeres, and resulted in the discovery of a potential nemaline myopathy model, suitable for the identification of genetic and small molecule inhibitors.
Collapse
Affiliation(s)
- Dávid Farkas
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Szilárd Szikora
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - A S Jijumon
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Tamás F Polgár
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
- Doctoral School of Theoretical Medicine, University of Szeged, Szeged, Hungary
| | - Roland Patai
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Mónika Ágnes Tóth
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - Beáta Bugyi
- University of Pécs, Medical School, Department of Biophysics, Pécs, Hungary
| | - Tamás Gajdos
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Péter Bíró
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Tibor Novák
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - Miklós Erdélyi
- Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
| | - József Mihály
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
- University of Szeged, Department of Genetics, Szeged, Hungary
| |
Collapse
|
3
|
Nguyen MT, Dash R, Jeong K, Lee W. Role of Actin-Binding Proteins in Skeletal Myogenesis. Cells 2023; 12:2523. [PMID: 37947600 PMCID: PMC10650911 DOI: 10.3390/cells12212523] [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] [Received: 09/28/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Maintenance of skeletal muscle quantity and quality is essential to ensure various vital functions of the body. Muscle homeostasis is regulated by multiple cytoskeletal proteins and myogenic transcriptional programs responding to endogenous and exogenous signals influencing cell structure and function. Since actin is an essential component in cytoskeleton dynamics, actin-binding proteins (ABPs) have been recognized as crucial players in skeletal muscle health and diseases. Hence, dysregulation of ABPs leads to muscle atrophy characterized by loss of mass, strength, quality, and capacity for regeneration. This comprehensive review summarizes the recent studies that have unveiled the role of ABPs in actin cytoskeletal dynamics, with a particular focus on skeletal myogenesis and diseases. This provides insight into the molecular mechanisms that regulate skeletal myogenesis via ABPs as well as research avenues to identify potential therapeutic targets. Moreover, this review explores the implications of non-coding RNAs (ncRNAs) targeting ABPs in skeletal myogenesis and disorders based on recent achievements in ncRNA research. The studies presented here will enhance our understanding of the functional significance of ABPs and mechanotransduction-derived myogenic regulatory mechanisms. Furthermore, revealing how ncRNAs regulate ABPs will allow diverse therapeutic approaches for skeletal muscle disorders to be developed.
Collapse
Affiliation(s)
- Mai Thi Nguyen
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
| | - Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea;
- Department of New Biology, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Republic of Korea
| | - Kyuho Jeong
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
| | - Wan Lee
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (K.J.)
- Channelopathy Research Center, Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang 10326, Republic of Korea
| |
Collapse
|
4
|
Nguyen MT, Ly QK, Kim HJ, Lee W. FLII Modulates the Myogenic Differentiation of Progenitor Cells via Actin Remodeling-Mediated YAP1 Regulation. Int J Mol Sci 2023; 24:14335. [PMID: 37762638 PMCID: PMC10531566 DOI: 10.3390/ijms241814335] [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] [Received: 07/16/2023] [Revised: 09/16/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
The dynamic rearrangement of the actin cytoskeleton plays an essential role in myogenesis, which is regulated by diverse mechanisms, such as mechanotransduction, modulation of the Hippo signaling pathway, control of cell proliferation, and the influence of morphological changes. Despite the recognized importance of actin-binding protein Flightless-1 (FLII) during actin remodeling, the role played by FLII in the differentiation of myogenic progenitor cells has not been explored. Here, we investigated the roles of FLII in the proliferation and differentiation of myoblasts. FLII was found to be enriched in C2C12 myoblasts, and its expression was stable during the early stages of differentiation but down-regulated in fully differentiated myotubes. Knockdown of FLII in C2C12 myoblasts resulted in filamentous actin (F-actin) accumulation and inhibited Yes-associated protein 1 (YAP1) phosphorylation, which triggers its nuclear translocation from the cytoplasm. Consequently, the expressions of YAP1 target genes, including PCNA, CCNB1, and CCND1, were induced, and the cell cycle and proliferation of myoblasts were promoted. Moreover, FLII knockdown significantly inhibited the expression of myogenic regulatory factors, i.e., MyoD and MyoG, thereby impairing myoblast differentiation, fusion, and myotube formation. Thus, our findings demonstrate that FLII is crucial for the differentiation of myoblasts via modulation of the F-actin/YAP1 axis and suggest that FLII is a putative novel therapeutic target for muscle wasting.
Collapse
Affiliation(s)
- Mai Thi Nguyen
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Quoc Kiet Ly
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Hyun-Jung Kim
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Wan Lee
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
- Channelopathy Research Center, Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Republic of Korea
| |
Collapse
|
5
|
Kuwabara Y, York AJ, Lin SC, Sargent MA, Grimes KM, Pirruccello JP, Molkentin JD. A human FLII gene variant alters sarcomeric actin thin filament length and predisposes to cardiomyopathy. Proc Natl Acad Sci U S A 2023; 120:e2213696120. [PMID: 37126682 PMCID: PMC10175844 DOI: 10.1073/pnas.2213696120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 04/07/2023] [Indexed: 05/03/2023] Open
Abstract
To better understand the genetic basis of heart disease, we identified a variant in the Flightless-I homolog (FLII) gene that generates a R1243H missense change and predisposes to cardiac remodeling across multiple previous human genome-wide association studies (GWAS). Since this gene is of unknown function in the mammalian heart we generated gain- and loss-of-function genetically altered mice, as well as knock-in mice with the syntenic R1245H amino acid substitution, which showed that Flii protein binds the sarcomeric actin thin filament and influences its length. Deletion of Flii from the heart, or mice with the R1245H amino acid substitution, show cardiomyopathy due to shortening of the actin thin filaments. Mechanistically, Flii is a known actin binding protein that we show associates with tropomodulin-1 (TMOD1) to regulate sarcomere thin filament length. Indeed, overexpression of leiomodin-2 in the heart, which lengthens the actin-containing thin filaments, partially rescued disease due to heart-specific deletion of Flii. Collectively, the identified FLII human variant likely increases cardiomyopathy risk through an alteration in sarcomere structure and associated contractile dynamics, like other sarcomere gene-based familial cardiomyopathies.
Collapse
Affiliation(s)
- Yasuhide Kuwabara
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - Allen J. York
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - Suh-Chin Lin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - Michelle A. Sargent
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - Kelly M. Grimes
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH45229
| | - James P. Pirruccello
- Division of Cardiology, University of California San Francisco, San Francisco, CA94158
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital and the University of Cincinnati, Cincinnati, OH45229
| |
Collapse
|
6
|
Zapater I Morales C, Carman PJ, Soffar DB, Windner SE, Dominguez R, Baylies MK. Drosophila Tropomodulin is required for multiple actin-dependent processes within developing myofibers. Development 2023; 150:dev201194. [PMID: 36806912 PMCID: PMC10112908 DOI: 10.1242/dev.201194] [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] [Received: 08/09/2022] [Accepted: 02/09/2023] [Indexed: 02/22/2023]
Abstract
Proper muscle contraction requires the assembly and maintenance of sarcomeres and myofibrils. Although the protein components of myofibrils are generally known, less is known about the mechanisms by which they individually function and together synergize for myofibril assembly and maintenance. For example, it is unclear how the disruption of actin filament (F-actin) regulatory proteins leads to the muscle weakness observed in myopathies. Here, we show that knockdown of Drosophila Tropomodulin (Tmod), results in several myopathy-related phenotypes, including reduction of muscle cell (myofiber) size, increased sarcomere length, disorganization and misorientation of myofibrils, ectopic F-actin accumulation, loss of tension-mediating proteins at the myotendinous junction, and misshaped and internalized nuclei. Our findings support and extend the tension-driven self-organizing myofibrillogenesis model. We show that, like its mammalian counterpart, Drosophila Tmod caps F-actin pointed-ends, and we propose that this activity is crucial for cellular processes in different locations within the myofiber that directly and indirectly contribute to the maintenance of muscle function. Our findings provide significant insights to the role of Tmod in muscle development, maintenance and disease.
Collapse
Affiliation(s)
- Carolina Zapater I Morales
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Peter J Carman
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David B Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Stefanie E Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Roberto Dominguez
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mary K Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| |
Collapse
|
7
|
Chen P, Levy DL. Regulation of organelle size and organization during development. Semin Cell Dev Biol 2023; 133:53-64. [PMID: 35148938 PMCID: PMC9357868 DOI: 10.1016/j.semcdb.2022.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 12/11/2022]
Abstract
During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.
Collapse
Affiliation(s)
- Pan Chen
- Institute of Biochemistry and Molecular Biology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
| |
Collapse
|
8
|
Amrute-Nayak M, Gand LV, Khan B, Holler T, Kefalakes E, Kosanke M, Kraft T, Nayak A. SENP7 deSUMOylase-governed transcriptional program coordinates sarcomere assembly and is targeted in muscle atrophy. Cell Rep 2022; 41:111702. [DOI: 10.1016/j.celrep.2022.111702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 08/16/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022] Open
|
9
|
Katti P, Hall AS, Parry HA, Ajayi PT, Kim Y, Willingham TB, Bleck CKE, Wen H, Glancy B. Mitochondrial network configuration influences sarcomere and myosin filament structure in striated muscles. Nat Commun 2022; 13:6058. [PMID: 36229433 PMCID: PMC9561657 DOI: 10.1038/s41467-022-33678-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
Sustained muscle contraction occurs through interactions between actin and myosin filaments within sarcomeres and requires a constant supply of adenosine triphosphate (ATP) from nearby mitochondria. However, it remains unclear how different physical configurations between sarcomeres and mitochondria alter the energetic support for contractile function. Here, we show that sarcomere cross-sectional area (CSA) varies along its length in a cell type-dependent manner where the reduction in Z-disk CSA relative to the sarcomere center is closely coordinated with mitochondrial network configuration in flies, mice, and humans. Further, we find myosin filaments near the sarcomere periphery are curved relative to interior filaments with greater curvature for filaments near mitochondria compared to sarcoplasmic reticulum. Finally, we demonstrate variable myosin filament lattice spacing between filament ends and filament centers in a cell type-dependent manner. These data suggest both sarcomere structure and myofilament interactions are influenced by the location and orientation of mitochondria within muscle cells.
Collapse
Affiliation(s)
- Prasanna Katti
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Hailey A Parry
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Peter T Ajayi
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuho Kim
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - T Bradley Willingham
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christopher K E Bleck
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Han Wen
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brian Glancy
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health Bethesda, Bethesda, MD, USA.
| |
Collapse
|
10
|
Ajayi PT, Katti P, Zhang Y, Willingham TB, Sun Y, Bleck CKE, Glancy B. Regulation of the evolutionarily conserved muscle myofibrillar matrix by cell type dependent and independent mechanisms. Nat Commun 2022; 13:2661. [PMID: 35562354 PMCID: PMC9106682 DOI: 10.1038/s41467-022-30401-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 04/29/2022] [Indexed: 12/29/2022] Open
Abstract
Skeletal muscles play a central role in human movement through forces transmitted by contraction of the sarcomere. We recently showed that mammalian sarcomeres are connected through frequent branches forming a singular, mesh-like myofibrillar matrix. However, the extent to which myofibrillar connectivity is evolutionarily conserved as well as mechanisms which regulate the specific architecture of sarcomere branching remain unclear. Here, we demonstrate the presence of a myofibrillar matrix in the tubular, but not indirect flight (IF) muscles within Drosophila melanogaster. Moreover, we find that loss of transcription factor H15 increases sarcomere branching frequency in the tubular jump muscles, and we show that sarcomere branching can be turned on in IF muscles by salm-mediated conversion to tubular muscles. Finally, we demonstrate that neurochondrin misexpression results in myofibrillar connectivity in IF muscles without conversion to tubular muscles. These data indicate an evolutionarily conserved myofibrillar matrix regulated by both cell-type dependent and independent mechanisms.
Collapse
Affiliation(s)
- Peter T Ajayi
- Muscle Energetics Laboratory, NHLBI, NIH, Bethesda, MD, 20892, USA
| | - Prasanna Katti
- Muscle Energetics Laboratory, NHLBI, NIH, Bethesda, MD, 20892, USA
| | - Yingfan Zhang
- Muscle Energetics Laboratory, NHLBI, NIH, Bethesda, MD, 20892, USA
| | | | - Ye Sun
- Electron Microscopy Core, NHLBI, NIH, Bethesda, MD, 20892, USA
| | | | - Brian Glancy
- Muscle Energetics Laboratory, NHLBI, NIH, Bethesda, MD, 20892, USA.
- NIAMS, NIH, Bethesda, MD, 20892, USA.
| |
Collapse
|
11
|
The Mechanisms of Thin Filament Assembly and Length Regulation in Muscles. Int J Mol Sci 2022; 23:ijms23105306. [PMID: 35628117 PMCID: PMC9140763 DOI: 10.3390/ijms23105306] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
The actin containing tropomyosin and troponin decorated thin filaments form one of the crucial components of the contractile apparatus in muscles. The thin filaments are organized into densely packed lattices interdigitated with myosin-based thick filaments. The crossbridge interactions between these myofilaments drive muscle contraction, and the degree of myofilament overlap is a key factor of contractile force determination. As such, the optimal length of the thin filaments is critical for efficient activity, therefore, this parameter is precisely controlled according to the workload of a given muscle. Thin filament length is thought to be regulated by two major, but only partially understood mechanisms: it is set by (i) factors that mediate the assembly of filaments from monomers and catalyze their elongation, and (ii) by factors that specify their length and uniformity. Mutations affecting these factors can alter the length of thin filaments, and in human cases, many of them are linked to debilitating diseases such as nemaline myopathy and dilated cardiomyopathy.
Collapse
|
12
|
Junion G, Jagla K. Diversification of muscle types in Drosophila embryos. Exp Cell Res 2022; 410:112950. [PMID: 34838813 DOI: 10.1016/j.yexcr.2021.112950] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/31/2022]
Abstract
Drosophila embryonic somatic muscles represent a simple and tractable model system to study the gene regulatory networks that control diversification of cell types. Somatic myogenesis in Drosophila is initiated by intrinsic action of the mesodermal master gene twist, which activates a cascade of transcriptional outputs including myogenic differentiation factor Mef2, which triggers all aspects of the myogenic differentiation program. In parallel, the expression of a combinatorial code of identity transcription factors (iTFs) defines discrete particular features of each muscle fiber, such as number of fusion events, and specific attachment to tendon cells or innervation, thus ensuring diversification of muscle types. Here, we take the example of a subset of lateral transverse (LT) muscles and discuss how the iTF code and downstream effector genes progressively define individual LT properties such as fusion program, attachment and innervation. We discuss new challenges in the field including the contribution of posttranscriptional and epitranscriptomic regulation of gene expression in the diversification of cell types.
Collapse
Affiliation(s)
- Guillaume Junion
- Genetics Reproduction and Development Institute (iGReD), CNRS UMR6293, INSERM U1103, University of Clermont Auvergne, Clermont-Ferrand, France
| | - Krzysztof Jagla
- Genetics Reproduction and Development Institute (iGReD), CNRS UMR6293, INSERM U1103, University of Clermont Auvergne, Clermont-Ferrand, France.
| |
Collapse
|
13
|
Nishimura Y, Shi S, Li Q, Bershadsky AD, Viasnoff V. Crosstalk between myosin II and formin functions in the regulation of force generation and actomyosin dynamics in stress fibers. Cells Dev 2021; 168:203736. [PMID: 34455135 DOI: 10.1016/j.cdev.2021.203736] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/23/2021] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
REF52 fibroblasts have a well-developed contractile machinery, the most prominent elements of which are actomyosin stress fibers with highly ordered organization of actin and myosin IIA filaments. The relationship between contractile activity and turnover dynamics of stress fibers is not sufficiently understood. Here, we simultaneously measured the forces exerted by stress fibers (using traction force microscopy or micropillar array sensors) and the dynamics of actin and myosin (using photoconversion-based monitoring of actin incorporation and high-resolution fluorescence microscopy of myosin II light chain). Our data revealed new features of the crosstalk between myosin II-driven contractility and stress fiber dynamics. During normal stress fiber turnover, actin incorporated all along the stress fibers and not only at focal adhesions. Incorporation of actin into stress fibers/focal adhesions, as well as actin and myosin II filaments flow along stress fibers, strongly depends on myosin II activity. Myosin II-dependent generation of traction forces does not depend on incorporation of actin into stress fibers per se, but still requires formin activity. This previously overlooked function of formins in maintenance of the actin cytoskeleton connectivity could be the main mechanism of formin involvement in traction force generation.
Collapse
Affiliation(s)
- Yukako Nishimura
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, 117411, Singapore; Division of Developmental Physiology, Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo 060-0815, Japan
| | - Shidong Shi
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, 117411, Singapore
| | - Qingsen Li
- IFOM-FIRC Institute of Molecular Oncology, Via Adamello, 16, 20139 Milan, Italy
| | - Alexander D Bershadsky
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, 117411, Singapore; Department of Molecular Cell Biology, Weizmann Institute of Science, 234 Herzl Street, POB 26, Rehovot 7610001, Israel.
| | - Virgile Viasnoff
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, 117411, Singapore; CNRS UMI 3639, Singapore; Department of Biological Sciences, National university of Singapore, S3 #05-01, 16 Science Drive 4, 117558, Singapore.
| |
Collapse
|