TGFβ signalling acts as a molecular brake of myoblast fusion.
Nat Commun, 2021/02/02;12(1):749.
Melendez J[1], Sieiro D[1, 2, 3], Salgado D[2, 4], Morin V[1], Dejardin MJ[1], Zhou C[5], Mullen AC[6], Marcelle C[7, 8]
Affiliations
PMID: 33531476DOI: 10.1038/s41467-020-20290-1
Impact factor: 17.694
Abstract
Fusion of nascent myoblasts to pre-existing myofibres is critical for skeletal muscle growth and repair. The vast majority of molecules known to regulate myoblast fusion are necessary in this process. Here, we uncover, through high-throughput in vitro assays and in vivo studies in the chicken embryo, that TGFβ (SMAD2/3-dependent) signalling acts specifically and uniquely as a molecular brake on muscle fusion. While constitutive activation of the pathway arrests fusion, its inhibition leads to a striking over-fusion phenotype. This dynamic control of TGFβ signalling in the embryonic muscle relies on a receptor complementation mechanism, prompted by the merging of myoblasts with myofibres, each carrying one component of the heterodimer receptor complex. The competence of myofibres to fuse is likely restored through endocytic degradation of activated receptors. Altogether, this study shows that muscle fusion relies on TGFβ signalling to regulate its pace.
MeSH terms
Animals; Cell Communication; Cell Differentiation; Cell Fusion; Chickens; Immunohistochemistry; In Situ Hybridization; Mice; Muscle Fibers, Skeletal; Myoblasts; Myofibrils; Signal Transduction; Transforming Growth Factor beta
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