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Ruan ZR, Yu Z, Xing C, Chen EH. Inter-organ steroid hormone signaling promotes myoblast fusion via direct transcriptional regulation of a single key effector gene. Curr Biol 2024; 34:1438-1452.e6. [PMID: 38513654 PMCID: PMC11003854 DOI: 10.1016/j.cub.2024.02.056] [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: 07/09/2023] [Revised: 12/24/2023] [Accepted: 02/23/2024] [Indexed: 03/23/2024]
Abstract
Steroid hormones regulate tissue development and physiology by modulating the transcription of a broad spectrum of genes. In insects, the principal steroid hormones, ecdysteroids, trigger the expression of thousands of genes through a cascade of transcription factors (TFs) to coordinate developmental transitions such as larval molting and metamorphosis. However, whether ecdysteroid signaling can bypass transcriptional hierarchies to exert its function in individual developmental processes is unclear. Here, we report that a single non-TF effector gene mediates the transcriptional output of ecdysteroid signaling in Drosophila myoblast fusion, a critical step in muscle development and differentiation. Specifically, we show that the 20-hydroxyecdysone (commonly referred to as "ecdysone") secreted from an extraembryonic tissue, amnioserosa, acts on embryonic muscle cells to directly activate the expression of antisocial (ants), which encodes an essential scaffold protein enriched at the fusogenic synapse. Not only is ants transcription directly regulated by the heterodimeric ecdysone receptor complex composed of ecdysone receptor (EcR) and ultraspiracle (USP) via ecdysone-response elements but also more strikingly, expression of ants alone is sufficient to rescue the myoblast fusion defect in ecdysone signaling-deficient mutants. We further show that EcR/USP and a muscle-specific TF Twist synergistically activate ants expression in vitro and in vivo. Taken together, our study provides the first example of a steroid hormone directly activating the expression of a single key non-TF effector gene to regulate a developmental process via inter-organ signaling and provides a new paradigm for understanding steroid hormone signaling in other developmental and physiological processes.
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Affiliation(s)
- Zhi-Rong Ruan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ze Yu
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Elizabeth H Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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2
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Cao C, Cai Y, Li Y, Li T, Zhang J, Hu Z, Zhang J. Characterization and comparative transcriptomic analysis of skeletal muscle in female Pekin duck and Hanzhong Ma duck during different growth stages using RNA-seq. Poult Sci 2023; 102:103122. [PMID: 37832186 PMCID: PMC10568565 DOI: 10.1016/j.psj.2023.103122] [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] [Received: 06/27/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 10/15/2023] Open
Abstract
Duck is an economically important poultry, and there is currently a major focus on improving its meat quality through breeding. There are wide variations in the growth regulation mechanisms of different duck breeds, that fundamental research on skeletal muscle growth is essential for understanding the regulation of unknown genes. The study aimed to broaden the understanding the duck skeletal muscle development and thereby to improve the performance of domestic ducks. In this study, RNA-seq data from skeletal muscles (breast muscle and leg muscle) of Pekin duck and Hanzhong Ma duck sampled at d 17, 21, and 27 of embryo (E17d, E21d, and E27d), as well as at 6-mo-old following birth (M6), to investigate and compare the mRNA temporal expression profiles and associated pathways that regulate skeletal myogenesis of different duck breeds. There were 331 to 1,440 annotated differentially expressed genes (DEGs) in breast muscle and 380 to 1,790 annotated DEGs in leg muscle from different databases between 2 duck breeds. Gene ontology (GO) enrichment in skeletal muscles indicated that these DEGs were mainly involved in biosynthetic process, developmental process, regulation of protein metabolic process and regulation of gene expression. KEGG analysis in skeletal muscles showed that a total of 41 DEGs were mapped to 7 KEGG pathways, including ECM-receptor interaction, focal adhesion, carbon metabolism, regulation of actin cytoskeleton, calcium signaling pathway, biosynthesis of amino acids and PPAR signaling pathway. The differential expression of 8 selected DEGs was verified by qRT-PCR, and the results were consistent with RNA-seq data. The identified DEGs, such as SDC, SPP1, PAK1, MYL9, PGK1, NOS1, PHGDH, TNNT2, FN1, and AQP4, were specially highlighted, indicating their associations with muscle development in the Pekin duck and Hanzhong Ma duck. This study provides a basis for revealing the differences in skeletal muscle development between Pekin duck and Hanzhong Ma duck.
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Affiliation(s)
- Chang Cao
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Yingjie Cai
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Yuxiao Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Tao Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Jiqiao Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Zhigang Hu
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China
| | - Jianqin Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, PR China.
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3
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Uechi H, Kuranaga E. Underlying mechanisms that ensure actomyosin-mediated directional remodeling of cell-cell contacts for multicellular movement: Tricellular junctions and negative feedback as new aspects underlying actomyosin-mediated directional epithelial morphogenesis: Tricellular junctions and negative feedback as new aspects underlying actomyosin-mediated directional epithelial morphogenesis. Bioessays 2023; 45:e2200211. [PMID: 36929512 DOI: 10.1002/bies.202200211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/18/2023]
Abstract
Actomyosin (actin-myosin II complex)-mediated contractile forces are central to the generation of multifaceted uni- and multi-cellular material properties and dynamics such as cell division, migration, and tissue morphogenesis. In the present article, we summarize our recent researches addressing molecular mechanisms that ensure actomyosin-mediated directional cell-cell junction remodeling, either shortening or extension, driving cell rearrangement for epithelial morphogenesis. Genetic perturbation clarified two points concerning cell-cell junction remodeling: an inhibitory mechanism against negative feedback in which actomyosin contractile forces, which are well known to induce cell-cell junction shortening, can concomitantly alter actin dynamics, oppositely leading to perturbation of the shortening; and tricellular junctions as a point that organizes extension of new cell-cell junctions after shortening. These findings highlight the notion that cells develop underpinning mechanisms to transform the multi-tasking property of actomyosin contractile forces into specific and proper cellular dynamics in space and time.
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Affiliation(s)
- Hiroyuki Uechi
- Laboratory for Histogenetic Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Erina Kuranaga
- Laboratory for Histogenetic Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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4
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Luo Z, Shi J, Pandey P, Ruan ZR, Sevdali M, Bu Y, Lu Y, Du S, Chen EH. The cellular architecture and molecular determinants of the zebrafish fusogenic synapse. Dev Cell 2022; 57:1582-1597.e6. [PMID: 35709765 PMCID: PMC10180866 DOI: 10.1016/j.devcel.2022.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 04/04/2022] [Accepted: 05/20/2022] [Indexed: 11/03/2022]
Abstract
Myoblast fusion is an indispensable process in skeletal muscle development and regeneration. Studies in Drosophila led to the discovery of the asymmetric fusogenic synapse, in which one cell invades its fusion partner with actin-propelled membrane protrusions to promote fusion. However, the timing and sites of vertebrate myoblast fusion remain elusive. Here, we show that fusion between zebrafish fast muscle cells is mediated by an F-actin-enriched invasive structure. Two cell adhesion molecules, Jam2a and Jam3b, are associated with the actin structure, with Jam2a being the major organizer. The Arp2/3 actin nucleation-promoting factors, WAVE and WASP-but not the bipartite fusogenic proteins, Myomaker or Myomixer-promote the formation of the invasive structure. Moreover, the convergence of fusogen-containing microdomains and the invasive protrusions is a prerequisite for cell membrane fusion. Thus, our study provides unprecedented insights into the cellular architecture and molecular determinants of the asymmetric fusogenic synapse in an intact vertebrate animal.
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Affiliation(s)
- Zhou Luo
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jun Shi
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Pratima Pandey
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zhi-Rong Ruan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Maria Sevdali
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ye Bu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yue Lu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shaojun Du
- Institute of Marine and Environmental Technology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Elizabeth H Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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5
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Inhibition of negative feedback for persistent epithelial cell-cell junction contraction by p21-activated kinase 3. Nat Commun 2022; 13:3520. [PMID: 35725726 PMCID: PMC9209458 DOI: 10.1038/s41467-022-31252-0] [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: 05/31/2019] [Accepted: 06/12/2022] [Indexed: 11/25/2022] Open
Abstract
Actin-mediated mechanical forces are central drivers of cellular dynamics. They generate protrusive and contractile dynamics, the latter of which are induced in concert with myosin II bundled at the site of contraction. These dynamics emerge concomitantly in tissues and even each cell; thus, the tight regulation of such bidirectional forces is important for proper cellular deformation. Here, we show that contractile dynamics can eventually disturb cell–cell junction contraction in the absence of p21-activated kinase 3 (Pak3). Upon Pak3 depletion, contractility induces the formation of abnormal actin protrusions at the shortening junctions, which causes decrease in E-cadherin levels at the adherens junctions and mislocalization of myosin II at the junctions before they enough shorten, compromising completion of junction shortening. Overexpressing E-cadherin restores myosin II distribution closely placed at the junctions and junction contraction. Our results suggest that contractility both induces and perturbs junction contraction and that the attenuation of such perturbations by Pak3 facilitates persistent junction shortening. Actin and myosin operate at cell–cell junctions during junctional shortening. Here the authors show that prolonged actomyosin contractility can compromise junctional shortening, and that Pak3 is required for attenuation of abnormal active protrusive structure and thus keeps junction contraction, appropriate E-cadherin distribution, and junction shortening in Drosophila.
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6
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Drosophila melanogaster: A Model System to Study Distinct Genetic Programs in Myoblast Fusion. Cells 2022; 11:cells11030321. [PMID: 35159130 PMCID: PMC8834112 DOI: 10.3390/cells11030321] [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: 12/04/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 11/25/2022] Open
Abstract
Muscle fibers are multinucleated cells that arise during embryogenesis through the fusion of mononucleated myoblasts. Myoblast fusion is a lifelong process that is crucial for the growth and regeneration of muscles. Understanding the molecular mechanism of myoblast fusion may open the way for novel therapies in muscle wasting and weakness. Recent reports in Drosophila and mammals have provided new mechanistic insights into myoblast fusion. In Drosophila, muscle formation occurs twice: during embryogenesis and metamorphosis. A fundamental feature is the formation of a cell–cell communication structure that brings the apposing membranes into close proximity and recruits possible fusogenic proteins. However, genetic studies suggest that myoblast fusion in Drosophila is not a uniform process. The complexity of the players involved in myoblast fusion can be modulated depending on the type of muscle that is formed. In this review, we introduce the different types of multinucleated muscles that form during Drosophila development and provide an overview in advances that have been made to understand the mechanism of myoblast fusion. Finally, we will discuss conceptual frameworks in cell–cell fusion in Drosophila and mammals.
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Rodríguez-Fdez S, Bustelo XR. Rho GTPases in Skeletal Muscle Development and Homeostasis. Cells 2021; 10:cells10112984. [PMID: 34831205 PMCID: PMC8616218 DOI: 10.3390/cells10112984] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
Rho guanosine triphosphate hydrolases (GTPases) are molecular switches that cycle between an inactive guanosine diphosphate (GDP)-bound and an active guanosine triphosphate (GTP)-bound state during signal transduction. As such, they regulate a wide range of both cellular and physiological processes. In this review, we will summarize recent work on the role of Rho GTPase-regulated pathways in skeletal muscle development, regeneration, tissue mass homeostatic balance, and metabolism. In addition, we will present current evidence that links the dysregulation of these GTPases with diseases caused by skeletal muscle dysfunction. Overall, this information underscores the critical role of a number of members of the Rho GTPase subfamily in muscle development and the overall metabolic balance of mammalian species.
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Affiliation(s)
- Sonia Rodríguez-Fdez
- Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain;
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
- Wellcome-MRC Institute of Metabolic Science and MRC Metabolic Diseases Unit, University of Cambridge, Cambridge CB2 0QQ, UK
- Correspondence: or
| | - Xosé R. Bustelo
- Molecular Mechanisms of Cancer Program, Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain;
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
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8
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Ozdowski EF, Wentzell JS, Engert SM, Abbott H, Sherwood NT. Suppression of spastin Mutant Phenotypes by Pak3 Loss Implicates a Role for Reactive Glia in AD-HSP. Front Neurosci 2020; 14:912. [PMID: 33013303 PMCID: PMC7499821 DOI: 10.3389/fnins.2020.00912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/06/2020] [Indexed: 11/13/2022] Open
Abstract
Neurodegenerative mechanisms due to mutations in spastin currently center on neuronal defects, primarily in microtubule and endomembrane regulation. Spastin loss in Drosophila larvae compromises neuronal microtubule distribution, alters synaptic bouton morphology, and weakens synaptic transmission at glutamatergic neuromuscular junction (NMJ) synapses. Pak3, a p21-activated kinase that promotes actin polymerization and filopodial projections, is required for these spastin mutant defects; animals lacking both genes have normal NMJs. Here we show that Pak3 is expressed in central and peripheral glial populations, and reduction of Pak3 specifically in subperineurial glial cells is sufficient to suppress the phenotypes associated with spastin loss. Subperineurial glia in the periphery ensheathe motor neuron axons and have been shown to extend actin-based projections that regulate synaptic terminals during normal NMJ development. We find that these subperineurial glial projections are Pak3-dependent and nearly twice as frequent in spastin mutants, while in Pak3, spastin double mutants, neither glial projections nor synaptic defects are observed. Spastin deficiency thus increases Pak3-dependent subperineurial glia activity, which is in turn required for neuronal defects. Our results demonstrate a central role for Pak3-mediated, altered glial behavior in the neuronal defects due to spastin loss, and suggest that a similar reactive glia-mediated mechanism may underlie human AD-HSP pathogenesis.
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Affiliation(s)
| | | | | | | | - Nina T. Sherwood
- Department of Biology, Duke University, Durham, NC, United States
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9
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Dynamin regulates the dynamics and mechanical strength of the actin cytoskeleton as a multifilament actin-bundling protein. Nat Cell Biol 2020; 22:674-688. [PMID: 32451441 PMCID: PMC7953826 DOI: 10.1038/s41556-020-0519-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/07/2020] [Indexed: 01/28/2023]
Abstract
The dynamin GTPase is known to bundle actin filaments, but the underlying molecular mechanism and physiological relevance remain unclear. Our genetic analyses revealed a function of dynamin in propelling invasive membrane protrusions during myoblast fusion in vivo. Using biochemistry, total internal reflection fluorescence microscopy, electron microscopy and cryo-electron tomography, we show that dynamin bundles actin while forming a helical structure. At its full capacity, each dynamin helix captures 12-16 actin filaments on the outer rim of the helix. GTP hydrolysis by dynamin triggers disassembly of fully assembled dynamin helices, releasing free dynamin dimers/tetramers and facilitating Arp2/3-mediated branched actin polymerization. The assembly/disassembly cycles of dynamin promote continuous actin bundling to generate mechanically stiff actin super-bundles. Super-resolution and immunogold platinum replica electron microscopy revealed dynamin along actin bundles at the fusogenic synapse. These findings implicate dynamin as a unique multifilament actin-bundling protein that regulates the dynamics and mechanical strength of the actin cytoskeletal network.
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10
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Abstract
Cell-cell fusion is indispensable for creating life and building syncytial tissues and organs. Ever since the discovery of cell-cell fusion, how cells join together to form zygotes and multinucleated syncytia has remained a fundamental question in cell and developmental biology. In the past two decades, Drosophila myoblast fusion has been used as a powerful genetic model to unravel mechanisms underlying cell-cell fusion in vivo. Many evolutionarily conserved fusion-promoting factors have been identified and so has a surprising and conserved cellular mechanism. In this review, we revisit key findings in Drosophila myoblast fusion and highlight the critical roles of cellular invasion and resistance in driving cell membrane fusion.
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Affiliation(s)
- Donghoon M Lee
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
| | - Elizabeth H Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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11
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Abstract
Cell-cell fusion is a fundamental process underlying fertilization, development, regeneration and physiology of metazoans. It is a multi-step process involving cell recognition and adhesion, actin cytoskeletal rearrangements, fusogen engagement, lipid mixing and fusion pore formation, ultimately resulting in the integration of two fusion partners. Here, we focus on the asymmetric actin cytoskeletal rearrangements at the site of fusion, known as the fusogenic synapse, which was first discovered during myoblast fusion in Drosophila embryos and later also found in mammalian muscle and non-muscle cells. At the asymmetric fusogenic synapse, actin-propelled invasive membrane protrusions from an attacking fusion partner trigger actomyosin-based mechanosensory responses in the receiving cell. The interplay between the invasive and resisting forces generated by the two fusion partners puts the fusogenic synapse under high mechanical tension and brings the two cell membranes into close proximity, promoting the engagement of fusogens to initiate fusion pore formation. In this Cell Science at a Glance article and the accompanying poster, we highlight the molecular, cellular and biophysical events at the asymmetric fusogenic synapse using Drosophila myoblast fusion as a model.
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Affiliation(s)
- Ji Hoon Kim
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Elizabeth H Chen
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA .,Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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12
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Ubiquitination and Long Non-coding RNAs Regulate Actin Cytoskeleton Regulators in Cancer Progression. Int J Mol Sci 2019; 20:ijms20122997. [PMID: 31248165 PMCID: PMC6627692 DOI: 10.3390/ijms20122997] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/16/2019] [Accepted: 06/17/2019] [Indexed: 12/15/2022] Open
Abstract
Actin filaments are a major component of the cytoskeleton in eukaryotic cells and play an important role in cancer metastasis. Dynamics and reorganization of actin filaments are regulated by numerous regulators, including Rho GTPases, PAKs (p21-activated kinases), ROCKs (Rho-associated coiled-coil containing kinases), LIMKs (LIM domain kinases), and SSH1 (slingshot family protein phosphate 1). Ubiquitination, as a ubiquitous post-transcriptional modification, deceases protein levels of actin cytoskeleton regulatory factors and thereby modulates the actin cytoskeleton. There is increasing evidence showing cytoskeleton regulation by long noncoding RNAs (lncRNAs) in cancer metastasis. However, which E3 ligases are activated for the ubiquitination of actin-cytoskeleton regulators involved in tumor metastasis remains to be fully elucidated. Moreover, it is not clear how lncRNAs influence the expression of actin cytoskeleton regulators. Here, we summarize physiological and pathological mechanisms of lncRNAs and ubiquitination control mediators of actin cytoskeleton regulators which that are involved in tumorigenesis and tumor progression. Finally, we briefly discuss crosstalk between ubiquitination and lncRNA control mediators of actin-cytoskeleton regulators in cancer.
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Joseph GA, Hung M, Goel AJ, Hong M, Rieder MK, Beckmann ND, Serasinghe MN, Chipuk JE, Devarakonda PM, Goldhamer DJ, Aldana-Hernandez P, Curtis J, Jacobs RL, Krauss RS. Late-onset megaconial myopathy in mice lacking group I Paks. Skelet Muscle 2019; 9:5. [PMID: 30791960 PMCID: PMC6383276 DOI: 10.1186/s13395-019-0191-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 02/12/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Group I Paks are serine/threonine kinases that function as major effectors of the small GTPases Rac1 and Cdc42, and they regulate cytoskeletal dynamics, cell polarity, and transcription. We previously demonstrated that Pak1 and Pak2 function redundantly to promote skeletal myoblast differentiation during postnatal development and regeneration in mice. However, the roles of Pak1 and Pak2 in adult muscle homeostasis are unknown. Choline kinase β (Chk β) is important for adult muscle homeostasis, as autosomal recessive mutations in CHKβ are associated with two human muscle diseases, megaconial congenital muscular dystrophy and proximal myopathy with focal depletion of mitochondria. METHODS We analyzed mice conditionally lacking Pak1 and Pak2 in the skeletal muscle lineage (double knockout (dKO) mice) over 1 year of age. Muscle integrity in dKO mice was assessed with histological stains, immunofluorescence, electron microscopy, and western blotting. Assays for mitochondrial respiratory complex function were performed, as was mass spectrometric quantification of products of choline kinase. Mice and cultured myoblasts deficient for choline kinase β (Chk β) were analyzed for Pak1/2 phosphorylation. RESULTS dKO mice developed an age-related myopathy. By 10 months of age, dKO mouse muscles displayed centrally-nucleated myofibers, fibrosis, and signs of degeneration. Disease severity occurred in a rostrocaudal gradient, hindlimbs more strongly affected than forelimbs. A distinctive feature of this myopathy was elongated and branched intermyofibrillar (megaconial) mitochondria, accompanied by focal mitochondrial depletion in the central region of the fiber. dKO muscles showed reduced mitochondrial respiratory complex I and II activity. These phenotypes resemble those of rmd mice, which lack Chkβ and are a model for human diseases associated with CHKβ deficiency. Pak1/2 and Chkβ activities were not interdependent in mouse skeletal muscle, suggesting a more complex relationship in regulation of mitochondria and muscle homeostasis. CONCLUSIONS Conditional loss of Pak1 and Pak2 in mice resulted in an age-dependent myopathy with similarity to mice and humans with CHKβ deficiency. Protein kinases are major regulators of most biological processes but few have been implicated in muscle maintenance or disease. Pak1/Pak2 dKO mice offer new insights into these processes.
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Affiliation(s)
- Giselle A Joseph
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.,Present address: Novartis Institutes for BioMedical Research, 181 Massachusetts Ave, Cambridge, MA, 02139, USA
| | - Margaret Hung
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA
| | - Aviva J Goel
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA
| | - Mingi Hong
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA
| | - Marysia-Kolbe Rieder
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA
| | - Noam D Beckmann
- Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA
| | - Madhavika N Serasinghe
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Jerry E Chipuk
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Parvathi M Devarakonda
- Department of Molecular & Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - David J Goldhamer
- Department of Molecular & Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Paulina Aldana-Hernandez
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Jonathan Curtis
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - René L Jacobs
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Robert S Krauss
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA. .,Graduate School of Biological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1020, New York, NY, 10029, USA.
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14
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Leikina E, Gamage DG, Prasad V, Goykhberg J, Crowe M, Diao J, Kozlov MM, Chernomordik LV, Millay DP. Myomaker and Myomerger Work Independently to Control Distinct Steps of Membrane Remodeling during Myoblast Fusion. Dev Cell 2018; 46:767-780.e7. [PMID: 30197239 DOI: 10.1016/j.devcel.2018.08.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/27/2018] [Accepted: 08/08/2018] [Indexed: 02/03/2023]
Abstract
Classic mechanisms for membrane fusion involve transmembrane proteins that assemble into complexes and dynamically alter their conformation to bend membranes, leading to mixing of membrane lipids (hemifusion) and fusion pore formation. Myomaker and Myomerger govern myoblast fusion and muscle formation but are structurally divergent from traditional fusogenic proteins. Here, we show that Myomaker and Myomerger independently mediate distinct steps in the fusion pathway, where Myomaker is involved in membrane hemifusion and Myomerger is necessary for fusion pore formation. Mechanistically, we demonstrate that Myomerger is required on the cell surface where its ectodomains stress membranes. Moreover, we show that Myomerger drives fusion completion in a heterologous system independent of Myomaker and that a Myomaker-Myomerger physical interaction is not required for function. Collectively, our data identify a stepwise cell fusion mechanism in myoblasts where different proteins are delegated to perform unique membrane functions essential for membrane coalescence.
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Affiliation(s)
- Evgenia Leikina
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dilani G Gamage
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Vikram Prasad
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joanna Goykhberg
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael Crowe
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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15
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Spectrin is a mechanoresponsive protein shaping fusogenic synapse architecture during myoblast fusion. Nat Cell Biol 2018; 20:688-698. [PMID: 29802406 PMCID: PMC6397639 DOI: 10.1038/s41556-018-0106-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 04/18/2018] [Indexed: 12/24/2022]
Abstract
Spectrin is a membrane skeletal protein best known for its structural role in maintaining cell shape and protecting cells from mechanical damage. Here, we report that α/βH-spectrin (βH is also called karst) dynamically accumulates and dissolves at the fusogenic synapse between fusing Drosophila muscle cells, where an attacking fusion partner invades its receiving partner with actin-propelled protrusions to promote cell fusion. Using genetics, cell biology, biophysics and mathematical modeling, we demonstrate that spectrin exhibits a mechanosensitive accumulation in response to shear deformation, which is highly elevated at the fusogenic synapse. The transiently accumulated spectrin network functions as a cellular fence to restrict the diffusion of cell adhesion molecules and a cellular sieve to constrict the invasive protrusions, thereby increasing the mechanical tension of the fusogenic synapse to promote cell membrane fusion. Our study reveals a function of spectrin as a mechanoresponsive protein and has general implications for understanding spectrin function in dynamic cellular processes.
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16
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Requirement of the fusogenic micropeptide myomixer for muscle formation in zebrafish. Proc Natl Acad Sci U S A 2017; 114:11950-11955. [PMID: 29078404 DOI: 10.1073/pnas.1715229114] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Skeletal muscle formation requires fusion of mononucleated myoblasts to form multinucleated myofibers. The muscle-specific membrane proteins myomaker and myomixer cooperate to drive mammalian myoblast fusion. Whereas myomaker is highly conserved across diverse vertebrate species, myomixer is a micropeptide that shows relatively weak cross-species conservation. To explore the functional conservation of myomixer, we investigated the expression and function of the zebrafish myomixer ortholog. Here we show that myomixer expression during zebrafish embryogenesis coincides with myoblast fusion, and genetic deletion of myomixer using CRISPR/Cas9 mutagenesis abolishes myoblast fusion in vivo. We also identify myomixer orthologs in other species of fish and reptiles, which can cooperate with myomaker and substitute for the fusogenic activity of mammalian myomixer. Sequence comparison of these diverse myomixer orthologs reveals key amino acid residues and a minimal fusogenic peptide motif that is necessary for promoting cell-cell fusion with myomaker. Our findings highlight the evolutionary conservation of the myomaker-myomixer partnership and provide insights into the molecular basis of myoblast fusion.
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17
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Group I Paks Promote Skeletal Myoblast Differentiation In Vivo and In Vitro. Mol Cell Biol 2017; 37:MCB.00222-16. [PMID: 27920252 DOI: 10.1128/mcb.00222-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 11/26/2016] [Indexed: 12/15/2022] Open
Abstract
Skeletal myogenesis is regulated by signal transduction, but the factors and mechanisms involved are not well understood. The group I Paks Pak1 and Pak2 are related protein kinases and direct effectors of Cdc42 and Rac1. Group I Paks are ubiquitously expressed and specifically required for myoblast fusion in Drosophila We report that both Pak1 and Pak2 are activated during mammalian myoblast differentiation. One pathway of activation is initiated by N-cadherin ligation and involves the cadherin coreceptor Cdo with its downstream effector, Cdc42. Individual genetic deletion of Pak1 and Pak2 in mice has no overt effect on skeletal muscle development or regeneration. However, combined muscle-specific deletion of Pak1 and Pak2 results in reduced muscle mass and a higher proportion of myofibers with a smaller cross-sectional area. This phenotype is exacerbated after repair to acute injury. Furthermore, primary myoblasts lacking Pak1 and Pak2 display delayed expression of myogenic differentiation markers and myotube formation. These results identify Pak1 and Pak2 as redundant regulators of myoblast differentiation in vitro and in vivo and as components of the promyogenic Ncad/Cdo/Cdc42 signaling pathway.
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18
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Krauss RS, Joseph GA, Goel AJ. Keep Your Friends Close: Cell-Cell Contact and Skeletal Myogenesis. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a029298. [PMID: 28062562 DOI: 10.1101/cshperspect.a029298] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Development of skeletal muscle is a multistage process that includes lineage commitment of multipotent progenitor cells, differentiation and fusion of myoblasts into multinucleated myofibers, and maturation of myofibers into distinct types. Lineage-specific transcriptional regulation lies at the core of this process, but myogenesis is also regulated by extracellular cues. Some of these cues are initiated by direct cell-cell contact between muscle precursor cells themselves or between muscle precursors and cells of other lineages. Examples of the latter include interaction of migrating neural crest cells with multipotent muscle progenitor cells, muscle interstitial cells with myoblasts, and neurons with myofibers. Among the signaling factors involved are Notch ligands and receptors, cadherins, Ig superfamily members, and Ephrins and Eph receptors. In this article we describe recent progress in this area and highlight open questions raised by the findings.
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Affiliation(s)
- Robert S Krauss
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Giselle A Joseph
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Aviva J Goel
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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19
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Lee G, Schwarz TL. Filamin, a synaptic organizer in Drosophila, determines glutamate receptor composition and membrane growth. eLife 2016; 5. [PMID: 27914199 PMCID: PMC5173320 DOI: 10.7554/elife.19991] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/23/2016] [Indexed: 11/27/2022] Open
Abstract
Filamin is a scaffolding protein that functions in many cells as an actin-crosslinker. FLN90, an isoform of the Drosophila ortholog Filamin/cheerio that lacks the actin-binding domain, is here shown to govern the growth of postsynaptic membrane folds and the composition of glutamate receptor clusters at the larval neuromuscular junction. Genetic and biochemical analyses revealed that FLN90 is present surrounding synaptic boutons. FLN90 is required in the muscle for localization of the kinase dPak and, downstream of dPak, for localization of the GTPase Ral and the exocyst complex to this region. Consequently, Filamin is needed for growth of the subsynaptic reticulum. In addition, in the absence of filamin, type-A glutamate receptor subunits are lacking at the postsynapse, while type-B subunits cluster correctly. Receptor composition is dependent on dPak, but independent of the Ral pathway. Thus two major aspects of synapse formation, morphological plasticity and subtype-specific receptor clustering, require postsynaptic Filamin. DOI:http://dx.doi.org/10.7554/eLife.19991.001
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Affiliation(s)
- GaYoung Lee
- The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Thomas L Schwarz
- The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
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20
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Role and organization of the actin cytoskeleton during cell-cell fusion. Semin Cell Dev Biol 2016; 60:121-126. [PMID: 27476112 DOI: 10.1016/j.semcdb.2016.07.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 11/23/2022]
Abstract
Cell-cell fusion is a ubiquitous process that underlies fertilization and development of eukaryotes. This process requires fusogenic machineries to promote plasma membrane merging, and also relies on the organization of dedicated sub-cortical cytoskeletal assemblies. This review describes the role of actin structures, so called actin fusion foci, essential for the fusion of two distinct cell types: Drosophila myoblast cells, which fuse to form myotubes, and sexually differentiated cells of the fission yeast Schizosaccharomyces pombe, which fuse to form a zygote. I describe the respective composition and organization of the two structures, discuss their proposed role in promoting plasma membrane apposition, and consider the universality of similar structures for cell-cell fusion.
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21
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Significance of kinase activity in the dynamic invadosome. Eur J Cell Biol 2016; 95:483-492. [PMID: 27465307 DOI: 10.1016/j.ejcb.2016.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/08/2016] [Accepted: 07/13/2016] [Indexed: 12/19/2022] Open
Abstract
Invadosomes are actin rich protrusive structures that facilitate invasive migration in multiple cell types. Comprised of invadopodia and podosomes, these highly dynamic structures adhere to and degrade the extracellular matrix, and are also thought to play a role in mechanosensing. Many extracellular signals have been implicated in invadosome stimulation, activating complex signalling cascades to drive the formation, activity and turnover of invadosomes. While the structural components of invadosomes have been well studied, the regulation of invadosome dynamics is still poorly understood. Protein kinases are essential to this regulation, affecting all stages of invadosome dynamics and allowing tight spatiotemporal control of their activity. Invadosome organisation and function have been linked to pathophysiological states such as cancer invasion and metastasis; therapeutic targeting of invadosome regulatory components is thus warranted. In this review, we discuss the involvement of kinase signalling in every stage of the invadosome life cycle and evaluate its significance.
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22
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Kuckwa J, Fritzen K, Buttgereit D, Rothenbusch-Fender S, Renkawitz-Pohl R. A new level of plasticity: Drosophila smooth-like testes muscles compensate failure of myoblast fusion. Development 2015; 143:329-38. [PMID: 26657767 PMCID: PMC4725342 DOI: 10.1242/dev.126730] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 11/28/2015] [Indexed: 12/26/2022]
Abstract
The testis of Drosophila resembles an individual testis tubule of mammals. Both are surrounded by a sheath of smooth muscles, which in Drosophila are multinuclear and originate from a pool of myoblasts that are set aside in the embryo and accumulate on the genital disc later in development. These muscle stem cells start to differentiate early during metamorphosis and give rise to all muscles of the inner male reproductive system. Shortly before the genital disc and the developing testes connect, multinuclear nascent myotubes appear on the anterior tips of the seminal vesicles. Here, we show that adhesion molecules are distinctly localized on the seminal vesicles; founder cell (FC)-like myoblasts express Dumbfounded (Duf) and Roughest (Rst), and fusion-competent myoblast (FCM)-like cells mainly express Sticks and stones (Sns). The smooth but multinuclear myotubes of the testes arose by myoblast fusion. RNAi-mediated attenuation of Sns or both Duf and Rst severely reduced the number of nuclei in the testes muscles. Duf and Rst probably act independently in this context. Despite reduced fusion in all of these RNAi-treated animals, myotubes migrated onto the testes, testes were shaped and coiled, muscle filaments were arranged as in the wild type and spermatogenesis proceeded normally. Hence, the testes muscles compensate for fusion defects so that the myofibres encircling the adult testes are indistinguishable from those of the wild type and male fertility is guaranteed. Summary:Drosophila testes muscles arise from stem cells and can compensate for fusion defects to safeguard fertility; this plasticity may compensate for the observed lack of satellite cells in Drosophila.
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Affiliation(s)
- Jessica Kuckwa
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Strasse 8, Marburg 35043, Germany
| | - Katharina Fritzen
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Strasse 8, Marburg 35043, Germany
| | - Detlev Buttgereit
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Strasse 8, Marburg 35043, Germany
| | - Silke Rothenbusch-Fender
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Strasse 8, Marburg 35043, Germany
| | - Renate Renkawitz-Pohl
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Strasse 8, Marburg 35043, Germany
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23
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Jiang C, Wang JH, Yue F, Kuang S. The brain expressed x-linked gene 1 (Bex1) regulates myoblast fusion. Dev Biol 2015; 409:16-25. [PMID: 26586200 DOI: 10.1016/j.ydbio.2015.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 11/07/2015] [Accepted: 11/11/2015] [Indexed: 11/28/2022]
Abstract
Skeletal muscle development (myogenesis) is a complex but precisely orchestrated process involving spatiotemporal regulation of the proliferation, differentiation and fusion of myogenic progenitor cells (myoblasts). Here we identify brain expressed x-linked gene 1 (Bex1) as a transient, developmentally regulated gene involved in myoblast fusion. Bex1 expression is undetectable in adult muscles or in quiescent muscle stem cells (satellite cells). During embryonic myogenesis, however, Bex1 is robustly expressed by myogenin(+) differentiating myoblasts, but not by Pax7(+) proliferating myoblasts. Interestingly, Bex1 is initially localized in the cytoplasm and then translocates into the nucleus. During adult muscle regeneration, Bex1 is highly expressed in newly regenerated myofibers and the expression is rapidly downregulated during maturation. Consistently, in cultured myoblasts, Bex1 is not expressed at the proliferation stage but transiently expressed upon induction of myogenic differentiation, following a similar cytoplasm to nucleus translocation pattern as seen in vivo. Using gain- and loss-of-function studies, we found that overexpression of Bex1 promotes the fusion of primary myoblasts without affecting myogenic differentiation and myogenin expression. Conversely, Bex1 knockout myoblasts exhibit obvious fusion defects, even though they express normal levels of myogenin and differentiate normally. These results elucidate a novel role of Bex1 in myogenesis through regulating myoblast fusion.
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Affiliation(s)
- Chunhui Jiang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, United States
| | - Jing-Hua Wang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, United States
| | - Feng Yue
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, United States
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, United States; Center for Cancer Research, Purdue University, West Lafayette, IN 47907, United States.
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24
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Felix M, Chayengia M, Ghosh R, Sharma A, Prasad M. Pak3 regulates apical-basal polarity in migrating border cells during Drosophila oogenesis. Development 2015; 142:3692-703. [PMID: 26395489 DOI: 10.1242/dev.125682] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/08/2015] [Indexed: 01/07/2023]
Abstract
Group cell migration is a highly coordinated process that is involved in a number of physiological events such as morphogenesis, wound healing and tumor metastasis. Unlike single cells, collectively moving cells are physically attached to each other and retain some degree of apical-basal polarity during the migratory phase. Although much is known about direction sensing, how polarity is regulated in multicellular movement remains unclear. Here we report the role of the protein kinase Pak3 in maintaining apical-basal polarity in migrating border cell clusters during Drosophila oogenesis. Pak3 is enriched in border cells and downregulation of its function impedes border cell movement. Time-lapse imaging suggests that Pak3 affects protrusive behavior of the border cell cluster, specifically regulating the stability and directionality of protrusions. Pak3 functions downstream of guidance receptor signaling to regulate the level and distribution of F-actin in migrating border cells. We also provide evidence that Pak3 genetically interacts with the lateral polarity marker Scribble and that it regulates JNK signaling in the moving border cells. Since Pak3 depletion results in mislocalization of several apical-basal polarity markers and overexpression of Jra rescues the polarity of the Pak3-depleted cluster, we propose that Pak3 functions through JNK signaling to modulate apical-basal polarity of the migrating border cell cluster. We also observe loss of apical-basal polarity in Rac1-depleted border cell clusters, suggesting that guidance receptor signaling functions through Rac GTPase and Pak3 to regulate the overall polarity of the cluster and mediate efficient collective movement of the border cells to the oocyte boundary.
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Affiliation(s)
- Martina Felix
- Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Mohanpur 741246, Nadia, West Bengal, India
| | - Mrinal Chayengia
- Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Mohanpur 741246, Nadia, West Bengal, India
| | - Ritabrata Ghosh
- Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Mohanpur 741246, Nadia, West Bengal, India
| | - Aditi Sharma
- Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Mohanpur 741246, Nadia, West Bengal, India
| | - Mohit Prasad
- Department of Biological Sciences, Indian Institute of Science Education & Research-Kolkata, Mohanpur Campus, Mohanpur 741246, Nadia, West Bengal, India
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25
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Deshpande RS, Grayson WL, Spector AA. A Modeling Insight into Adipose-Derived Stem Cell Myogenesis. PLoS One 2015; 10:e0137918. [PMID: 26378788 PMCID: PMC4574760 DOI: 10.1371/journal.pone.0137918] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 08/23/2015] [Indexed: 12/02/2022] Open
Abstract
Adipose-derived stem cells (ASCs) are clinically important in regenerative medicine as they are relatively easy to obtain, are characterized by low morbidity, and can differentiate into myogenic progenitor cells. Although studies have elucidated the principal markers, PAX7, Desmin, MyoD, and MHC, the underlying mechanisms are not completely understood. This motivates the application of computational methods to facilitate greater understanding of such processes. In the following, we present a multi-stage kinetic model comprising a system of ordinary differential equations (ODEs). We sought to model ASC differentiation using data from a static culture, where no strain is applied, and a dynamic culture, where 10% strain is applied. The coefficients of the equations have been modulated by those experimental data points. To correctly represent the trajectories, various switches and a feedback factor based on total cell number have been introduced to better represent the biology of ASC differentiation. Furthermore, the model has then been applied to predict ASC fate for strains different from those used in the experimental conditions and for times longer than the duration of the experiment. Analysis of the results reveals unique characteristics of ASC myogenesis under dynamic conditions of the applied strain.
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Affiliation(s)
- Rajiv S. Deshpande
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Warren L. Grayson
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Alexander A. Spector
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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26
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Zheng Y, Wang W, Liu B, Deng H, Uster E, Pan D. Identification of Happyhour/MAP4K as Alternative Hpo/Mst-like Kinases in the Hippo Kinase Cascade. Dev Cell 2015; 34:642-55. [PMID: 26364751 PMCID: PMC4589524 DOI: 10.1016/j.devcel.2015.08.014] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/14/2015] [Accepted: 08/20/2015] [Indexed: 10/25/2022]
Abstract
In Drosophila and mammals, the canonical Hippo kinase cascade is mediated by Hpo/Mst acting through the intermediary kinase Wts/Lats to phosphorylate the transcriptional coactivator Yki/YAP/TAZ. Despite recent reports linking Yki/YAP/TAZ activity to the actin cytoskeleton, the underlying mechanisms are poorly understood and/or controversial. Using Drosophila imaginal discs as an in vivo model, we show that Wts, but not Hpo, is genetically indispensable for cytoskeleton-mediated subcellular localization of Yki. Through a systematic screen, we identify the Ste-20 kinase Happyhour (Hppy) and its mammalian counterpart MAP4K1/2/3/5 as an alternative kinase that phosphorylates the hydrophobic motif of Wts/Lats in a similar manner as Hpo/Mst. Consistent with their redundant function as activating kinases of Wts/Lats, combined loss of Hpo/Mst and Hppy/MAP4K abolishes cytoskeleton-mediated regulation of Yki/YAP subcellular localization, as well as YAP cytoplasmic translocation induced by contact inhibition. These Hpo/Mst-like kinases provide an expanded view of the Hippo kinase cascade in development and physiology.
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Affiliation(s)
- Yonggang Zheng
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wei Wang
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Liu
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hua Deng
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eliza Uster
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Duojia Pan
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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27
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Buffolo M, Batista Possidonio AC, Mermelstein C, Araujo H. A conserved role for calpains during myoblast fusion. Genesis 2015; 53:417-30. [DOI: 10.1002/dvg.22870] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/17/2015] [Accepted: 06/25/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Marcio Buffolo
- Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto De Ciências Biomédicas, Universidade Federal Do Rio De Janeiro; Rio De Janeiro Brazil
- Laboratório de Biologia Molecular do Desenvolvimento, Instituto De Ciências Biomédicas, Universidade Federal Do Rio De Janeiro; Rio De Janeiro Brazil
| | - Ana Claudia Batista Possidonio
- Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto De Ciências Biomédicas, Universidade Federal Do Rio De Janeiro; Rio De Janeiro Brazil
| | - Claudia Mermelstein
- Laboratório de Diferenciação Muscular e Citoesqueleto, Instituto De Ciências Biomédicas, Universidade Federal Do Rio De Janeiro; Rio De Janeiro Brazil
| | - Helena Araujo
- Laboratório de Biologia Molecular do Desenvolvimento, Instituto De Ciências Biomédicas, Universidade Federal Do Rio De Janeiro; Rio De Janeiro Brazil
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28
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Frese S, Ruebner M, Suhr F, Konou TM, Tappe KA, Toigo M, Jung HH, Henke C, Steigleder R, Strissel PL, Huebner H, Beckmann MW, van der Keylen P, Schoser B, Schiffer T, Frese L, Bloch W, Strick R. Long-Term Endurance Exercise in Humans Stimulates Cell Fusion of Myoblasts along with Fusogenic Endogenous Retroviral Genes In Vivo. PLoS One 2015; 10:e0132099. [PMID: 26154387 PMCID: PMC4495930 DOI: 10.1371/journal.pone.0132099] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022] Open
Abstract
Myogenesis is defined as growth, differentiation and repair of muscles where cell fusion of myoblasts to multinucleated myofibers is one major characteristic. Other cell fusion events in humans are found with bone resorbing osteoclasts and placental syncytiotrophoblasts. No unifying gene regulation for natural cell fusions has been found. We analyzed skeletal muscle biopsies of competitive cyclists for muscle-specific attributes and expression of human endogenous retrovirus (ERV) envelope genes due to their involvement in cell fusion of osteoclasts and syncytiotrophoblasts. Comparing muscle biopsies from post- with the pre-competitive seasons a significant 2.25-fold increase of myonuclei/mm fiber, a 2.38-fold decrease of fiber area/nucleus and a 3.1-fold decrease of satellite cells (SCs) occurred. We propose that during the pre-competitive season SC proliferation occurred following with increased cell fusion during the competitive season. Expression of twenty-two envelope genes of muscle biopsies demonstrated a significant increase of putative muscle-cell fusogenic genes Syncytin-1 and Syncytin-3, but also for the non-fusogenic erv3. Immunohistochemistry analyses showed that Syncytin-1 mainly localized to the sarcolemma of myofibers positive for myosin heavy-chain isotypes. Cellular receptors SLC1A4 and SLC1A5 of Syncytin-1 showed significant decrease of expression in post-competitive muscles compared with the pre-competitive season, but only SLC1A4 protein expression localized throughout the myofiber. Erv3 protein was strongly expressed throughout the myofiber, whereas envK1-7 localized to SC nuclei and myonuclei. Syncytin-1 transcription factors, PPARγ and RXRα, showed no protein expression in the myofiber, whereas the pCREB-Ser133 activator of Syncytin-1 was enriched to SC nuclei and myonuclei. Syncytin-1, Syncytin-3, SLC1A4 and PAX7 gene regulations along with MyoD1 and myogenin were verified during proliferating or actively-fusing human primary myoblast cell cultures, resembling muscle biopsies of cyclists. Myoblast treatment with anti-Synycytin-1 abrogated cell fusion in vitro. Our findings support functional roles for ERV envelope proteins, especially Syncytin-1, contributing to cell fusion of myotubes.
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Affiliation(s)
- Sebastian Frese
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
- University Hospital Zurich, Department of Neurology, Frauenklinikstrasse, Zurich, Switzerland
- Institute of Human Movement Sciences and Sport, Exercise Physiology, ETH Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Matthias Ruebner
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Frank Suhr
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Thierry M. Konou
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Kim A. Tappe
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Marco Toigo
- Institute of Human Movement Sciences and Sport, Exercise Physiology, ETH Zurich, Winterthurerstrasse, Zurich, Switzerland
- University of Zurich, Balgrist University Hospital, Department of Orthopaedics, Forchstrasse, Zurich, Switzerland
| | - Hans H. Jung
- University Hospital Zurich, Department of Neurology, Frauenklinikstrasse, Zurich, Switzerland
| | - Christine Henke
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Ruth Steigleder
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Pamela L. Strissel
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Hanna Huebner
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Matthias W. Beckmann
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Piet van der Keylen
- Institute of Anatomy, Friedrich-Alexander University of Erlangen-Nürnberg, Krankenhausstrasse, Erlangen, Germany
| | - Benedikt Schoser
- Ludwig Maximilian University Munich, Department of Neurology, Friedrich Baur Institute, Ziemssenstrasse, Munich, Germany
| | - Thorsten Schiffer
- German Sport University Cologne, Outpatient Clinic for Sports Traumatology and Public Health Consultation, Am Sportpark Muengersdorf, Cologne, Germany
| | - Laura Frese
- University Hospital and University Zurich, Division of Surgical Research, Raemistrasse, Zurich, Switzerland
| | - Wilhelm Bloch
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
- The German Research Centre of Elite Sport, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Reiner Strick
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
- * E-mail:
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Kim JH, Jin P, Duan R, Chen EH. Mechanisms of myoblast fusion during muscle development. Curr Opin Genet Dev 2015; 32:162-70. [PMID: 25989064 DOI: 10.1016/j.gde.2015.03.006] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/13/2015] [Accepted: 03/17/2015] [Indexed: 01/24/2023]
Abstract
The development and regeneration of skeletal muscle require the fusion of mononucleated muscle cells to form multinucleated, contractile muscle fibers. Studies using a simple genetic model, Drosophila melanogaster, have discovered many evolutionarily conserved fusion-promoting factors in vivo. Recent work in zebrafish and mouse also identified several vertebrate-specific factors required for myoblast fusion. Here, we integrate progress in multiple in vivo systems and highlight conceptual advance in understanding how muscle cell membranes are brought together for fusion. We focus on the molecular machinery at the fusogenic synapse and present a three-step model to describe the molecular and cellular events leading to fusion pore formation.
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Affiliation(s)
- Ji Hoon Kim
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Peng Jin
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Rui Duan
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Elizabeth H Chen
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States.
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Haralalka S, Abmayr SM. Tracing myoblast fusion in Drosophila embryos by fluorescent actin probes. Methods Mol Biol 2015; 1313:149-64. [PMID: 25947663 DOI: 10.1007/978-1-4939-2703-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Myoblast fusion in the Drosophila embryo is a highly elaborate process that is initiated by Founder Cells and Fusion-Competent Myoblasts (FCMs). It occurs through an asymmetric event in which actin foci assemble in the FCMs at points of cell-cell contact and direct the formation of membrane protrusions that drive fusion. Herein, we describe the approach that we have used to image in living embryos the highly dynamic actin foci and actin-rich projections that precede myoblast fusion. We discuss resources currently available for imaging actin and myogenesis, and our experience with these resources if available. This technical report is not intended to be comprehensive on providing instruction on standard microscopy practices or software utilization. However, we discuss microscope parameters that we have used in data collection, and our experience with image processing tools in data analysis.
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Affiliation(s)
- Shruti Haralalka
- Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO, 64110, USA
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31
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Schulman VK, Dobi KC, Baylies MK. Morphogenesis of the somatic musculature in Drosophila melanogaster. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:313-34. [PMID: 25758712 DOI: 10.1002/wdev.180] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/28/2015] [Accepted: 01/30/2015] [Indexed: 12/22/2022]
Abstract
In Drosophila melanogaster, the somatic muscle system is first formed during embryogenesis, giving rise to the larval musculature. Later during metamorphosis, this system is destroyed and replaced by an entirely new set of muscles in the adult fly. Proper formation of the larval and adult muscles is critical for basic survival functions such as hatching and crawling (in the larva), walking and flying (in the adult), and feeding (at both larval and adult stages). Myogenesis, from mononucleated muscle precursor cells to multinucleated functional muscles, is driven by a number of cellular processes that have begun to be mechanistically defined. Once the mesodermal cells destined for the myogenic lineage have been specified, individual myoblasts fuse together iteratively to form syncytial myofibers. Combining cytoplasmic contents demands a level of intracellular reorganization that, most notably, leads to redistribution of the myonuclei to maximize internuclear distance. Signaling from extending myofibers induces terminal tendon cell differentiation in the ectoderm, which results in secure muscle-tendon attachments that are critical for muscle contraction. Simultaneously, muscles become innervated and undergo sarcomerogenesis to establish the contractile apparatus that will facilitate movement. The cellular mechanisms governing these morphogenetic events share numerous parallels to mammalian development, and the basic unit of all muscle, the myofiber, is conserved from flies to mammals. Thus, studies of Drosophila myogenesis and comparisons to muscle development in other systems highlight conserved regulatory programs of biomedical relevance to general muscle biology and studies of muscle disease.
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Affiliation(s)
- Victoria K Schulman
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA.,Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Krista C Dobi
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Mary K Baylies
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA.,Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
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32
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Kim JH, Ren Y, Ng WP, Li S, Son S, Kee YS, Zhang S, Zhang G, Fletcher DA, Robinson DN, Chen EH. Mechanical tension drives cell membrane fusion. Dev Cell 2015; 32:561-73. [PMID: 25684354 DOI: 10.1016/j.devcel.2015.01.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 11/14/2014] [Accepted: 01/10/2015] [Indexed: 01/05/2023]
Abstract
Membrane fusion is an energy-consuming process that requires tight juxtaposition of two lipid bilayers. Little is known about how cells overcome energy barriers to bring their membranes together for fusion. Previously, we have shown that cell-cell fusion is an asymmetric process in which an "attacking" cell drills finger-like protrusions into the "receiving" cell to promote cell fusion. Here, we show that the receiving cell mounts a Myosin II (MyoII)-mediated mechanosensory response to its invasive fusion partner. MyoII acts as a mechanosensor, which directs its force-induced recruitment to the fusion site, and the mechanosensory response of MyoII is amplified by chemical signaling initiated by cell adhesion molecules. The accumulated MyoII, in turn, increases cortical tension and promotes fusion pore formation. We propose that the protrusive and resisting forces from fusion partners put the fusogenic synapse under high mechanical tension, which helps to overcome energy barriers for membrane apposition and drives cell membrane fusion.
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Affiliation(s)
- Ji Hoon Kim
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yixin Ren
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Win Pin Ng
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Shuo Li
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sungmin Son
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Yee-Seir Kee
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shiliang Zhang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guofeng Zhang
- Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD 20892, USA
| | - Daniel A Fletcher
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Elizabeth H Chen
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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33
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Haralalka S, Shelton C, Cartwright HN, Guo F, Trimble R, Kumar RP, Abmayr SM. Live imaging provides new insights on dynamic F-actin filopodia and differential endocytosis during myoblast fusion in Drosophila. PLoS One 2014; 9:e114126. [PMID: 25474591 PMCID: PMC4256407 DOI: 10.1371/journal.pone.0114126] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/28/2014] [Indexed: 11/29/2022] Open
Abstract
The process of myogenesis includes the recognition, adhesion, and fusion of committed myoblasts into multinucleate syncytia. In the larval body wall muscles of Drosophila, this elaborate process is initiated by Founder Cells and Fusion-Competent Myoblasts (FCMs), and cell adhesion molecules Kin-of-IrreC (Kirre) and Sticks-and-stones (Sns) on their respective surfaces. The FCMs appear to provide the driving force for fusion, via the assembly of protrusions associated with branched F-actin and the WASp, SCAR and Arp2/3 pathways. In the present study, we utilize the dorsal pharyngeal musculature that forms in the Drosophila embryo as a model to explore myoblast fusion and visualize the fusion process in live embryos. These muscles rely on the same cell types and genes as the body wall muscles, but are amenable to live imaging since they do not undergo extensive morphogenetic movement during formation. Time-lapse imaging with F-actin and membrane markers revealed dynamic FCM-associated actin-enriched protrusions that rapidly extend and retract into the myotube from different sites within the actin focus. Ultrastructural analysis of this actin-enriched area showed that they have two morphologically distinct structures: wider invasions and/or narrow filopodia that contain long linear filaments. Consistent with this, formin Diaphanous (Dia) and branched actin nucleator, Arp3, are found decorating the filopodia or enriched at the actin focus, respectively, indicating that linear actin is present along with branched actin at sites of fusion in the FCM. Gain-of-function Dia and loss-of-function Arp3 both lead to fusion defects, a decrease of F-actin foci and prominent filopodia from the FCMs. We also observed differential endocytosis of cell surface components at sites of fusion, with actin reorganizing factors, WASp and SCAR, and Kirre remaining on the myotube surface and Sns preferentially taken up with other membrane proteins into early endosomes and lysosomes in the myotube.
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Affiliation(s)
- Shruti Haralalka
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Claude Shelton
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Heather N. Cartwright
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Fengli Guo
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Rhonda Trimble
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Ram P. Kumar
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
| | - Susan M. Abmayr
- Stowers Institute for Medical Research, Kansas City, Missouri, 64110, United States of America
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, Kansas, 66160, United States of America
- * E-mail:
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34
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Wang R, Dang YL, Zheng R, Li Y, Li W, Lu X, Wang LJ, Zhu C, Lin HY, Wang H. Live cell imaging of in vitro human trophoblast syncytialization. Biol Reprod 2014; 90:117. [PMID: 24740598 DOI: 10.1095/biolreprod.113.114892] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Human trophoblast syncytialization, a process of cell-cell fusion, is one of the most important yet least understood events during placental development. Investigating the fusion process in a placenta in vivo is very challenging given the complexity of this process. Application of primary cultured cytotrophoblast cells isolated from term placentas and BeWo cells derived from human choriocarcinoma formulates a biphasic strategy to achieve the mechanism of trophoblast cell fusion, as the former can spontaneously fuse to form the multinucleated syncytium and the latter is capable of fusing under the treatment of forskolin (FSK). Live-cell imaging is a powerful tool that is widely used to investigate many physiological or pathological processes in various animal models or humans; however, to our knowledge, the mechanism of trophoblast cell fusion has not been reported using a live- cell imaging manner. In this study, a live-cell imaging system was used to delineate the fusion process of primary term cytotrophoblast cells and BeWo cells. By using live staining with Hoechst 33342 or cytoplasmic dyes or by stably transfecting enhanced green fluorescent protein (EGFP) and DsRed2-Nuc reporter plasmids, we observed finger-like protrusions on the cell membranes of fusion partners before fusion and the exchange of cytoplasmic contents during fusion. In summary, this study provides the first video recording of the process of trophoblast syncytialization. Furthermore, the various live-cell imaging systems used in this study will help to yield molecular insights into the syncytialization process during placental development.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Yan-Li Dang
- Department of Obstetrics and Gynecology, the 306th Hospital of PLA, Beijing, China
| | - Ru Zheng
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Yue Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Weiwei Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China College of Life Science, Beijing Normal University, Beijing, China
| | - Xiaoyin Lu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China Graduate School of Chinese Academy of Sciences, Beijing, China
| | - Li-Juan Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Cheng Zhu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Hai-Yan Lin
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Hongmei Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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35
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Abstract
Muscle fibers form as a result of myoblast fusion, yet the cell surface receptors regulating this process are unknown in vertebrates. In Drosophila, myoblast fusion involves the activation of the Rac pathway by the guanine nucleotide exchange factor Myoblast City and its scaffolding protein ELMO, downstream of cell-surface cell-adhesion receptors. We previously showed that the mammalian ortholog of Myoblast City, DOCK1, functions in an evolutionarily conserved manner to promote myoblast fusion in mice. In search for regulators of myoblast fusion, we identified the G-protein coupled receptor brain-specific angiogenesis inhibitor (BAI3) as a cell surface protein that interacts with ELMO. In cultured cells, BAI3 or ELMO1/2 loss of function severely impaired myoblast fusion without affecting differentiation and cannot be rescued by reexpression of BAI3 mutants deficient in ELMO binding. The related BAI protein family member, BAI1, is functionally distinct from BAI3, because it cannot rescue the myoblast fusion defects caused by the loss of BAI3 function. Finally, embryonic muscle precursor expression of a BAI3 mutant unable to bind ELMO was sufficient to block myoblast fusion in vivo. Collectively, our findings provide a role for BAI3 in the relay of extracellular fusion signals to their intracellular effectors, identifying it as an essential transmembrane protein for embryonic vertebrate myoblast fusion.
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36
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Shilagardi K, Li S, Luo F, Marikar F, Duan R, Jin P, Kim JH, Murnen K, Chen EH. Actin-propelled invasive membrane protrusions promote fusogenic protein engagement during cell-cell fusion. Science 2013; 340:359-63. [PMID: 23470732 DOI: 10.1126/science.1234781] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cell-cell fusion is critical for the conception, development, and physiology of multicellular organisms. Although cellular fusogenic proteins and the actin cytoskeleton are implicated in cell-cell fusion, it remains unclear whether and how they coordinate to promote plasma membrane fusion. We reconstituted a high-efficiency, inducible cell fusion culture system in the normally nonfusing Drosophila S2R+ cells. Both fusogenic proteins and actin cytoskeletal rearrangements were necessary for cell fusion, and in combination they were sufficient to impart fusion competence. Localized actin polymerization triggered by specific cell-cell or cell-matrix adhesion molecules propelled invasive cell membrane protrusions, which in turn promoted fusogenic protein engagement and plasma membrane fusion. This de novo cell fusion culture system reveals a general role for actin-propelled invasive membrane protrusions in driving fusogenic protein engagement during cell-cell fusion.
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Affiliation(s)
- Khurts Shilagardi
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Aguilar PS, Baylies MK, Fleissner A, Helming L, Inoue N, Podbilewicz B, Wang H, Wong M. Genetic basis of cell-cell fusion mechanisms. Trends Genet 2013; 29:427-37. [PMID: 23453622 DOI: 10.1016/j.tig.2013.01.011] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 01/15/2013] [Accepted: 01/25/2013] [Indexed: 12/22/2022]
Abstract
Cell-cell fusion in sexually reproducing organisms is a mechanism to merge gamete genomes and, in multicellular organisms, it is a strategy to sculpt organs, such as muscle, bone, and placenta. Moreover, this mechanism has been implicated in pathological conditions, such as infection and cancer. Studies of genetic model organisms have uncovered a unifying principle: cell fusion is a genetically programmed process. This process can be divided in three stages: competence (cell induction and differentiation); commitment (cell determination, migration, and adhesion); and cell fusion (membrane merging and cytoplasmic mixing). Recent work has led to the discovery of fusogens, which are cell fusion proteins that are necessary and sufficient to fuse cell membranes. Two unrelated families of fusogens have been discovered, one in mouse placenta and one in Caenorhabditis elegans (syncytins and F proteins, respectively). Current research aims to identify new fusogens and determine the mechanisms by which they merge membranes.
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Affiliation(s)
- Pablo S Aguilar
- Cellular Membranes Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo 11400, Uruguay
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38
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Bonn BR, Rudolf A, Hornbruch-Freitag C, Daum G, Kuckwa J, Kastl L, Buttgereit D, Renkawitz-Pohl R. Myosin heavy chain-like localizes at cell contact sites during Drosophila myoblast fusion and interacts in vitro with Rolling pebbles 7. Exp Cell Res 2012; 319:402-16. [PMID: 23246571 DOI: 10.1016/j.yexcr.2012.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 12/04/2012] [Accepted: 12/05/2012] [Indexed: 11/29/2022]
Abstract
Besides representing the sarcomeric thick filaments, myosins are involved in many cellular transport and motility processes. Myosin heavy chains are grouped into 18 classes. Here we show that in Drosophila, the unconventional group XVIII myosin heavy chain-like (Mhcl) is transcribed in the mesoderm of embryos, most prominently in founder cells (FCs). An ectopically expressed GFP-tagged Mhcl localizes in the growing muscle at cell-cell contacts towards the attached fusion competent myoblast (FCM). We further show that Mhcl interacts in vitro with the essential fusion protein Rolling pebbles 7 (Rols7), which is part of a protein complex established at cell contact sites (Fusion-restricted Myogenic-Adhesive Structure or FuRMAS). Here, branched F-actin is likely needed to widen the fusion pore and to integrate the myoblast into the growing muscle. We show that the localization of Mhcl is dependent on the presence of Rols7, and we postulate that Mhcl acts at the FuRMAS as an actin motor protein. We further show that Mhcl deficient embryos develop a wild-type musculature. We thus propose that Mhcl functions redundantly to other myosin heavy chains in myoblasts. Lastly, we found that the protein is detectable adjacent to the sarcomeric Z-discs, suggesting an additional function in mature muscles.
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Affiliation(s)
- Bettina R Bonn
- Developmental Biology, Department of Biology, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, 35037 Marburg, Germany
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