WIP/WASp-Based Actin-Polymerization Machinery Is Essential for Myoblast Fusion in Drosophila

• Published in: Developmental cell Vol. 12; no. 4; pp. 557 - 569
• Main Authors: Massarwa, R'ada, Carmon, Shari, Shilo, Ben-Zion, Schejter, Eyal D.
• Format: Journal Article
• Language: English
• Published: Cambridge, MA Elsevier Inc 01-04-2007; Cell Press
• Subjects: Actins - metabolism; Animals; Animals, Genetically Modified; Biological and medical sciences; Cell differentiation, maturation, development, hematopoiesis; Cell Fusion; Cell Line; Cell physiology; CELLBIO; DEVBIO; Drosophila; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila melanogaster - metabolism; Drosophila melanogaster - physiology; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Embryo, Nonmammalian; Fundamental and applied biological sciences. Psychology; Hymenoptera; Immunoglobulins - metabolism; Models, Biological; Molecular and cellular biology; Muscle Development; Muscles - embryology; Muscles - metabolism; Myoblasts - metabolism; Myoblasts - physiology; Wiskott-Aldrich Syndrome Protein - genetics; Wiskott-Aldrich Syndrome Protein - metabolism; CELLBIO; DEVBIO; Actin; Arthropoda; Insecta; Development; Myoblast; Invertebrata; Drosophila melanogaster; Essential; Diptera; Drosophilidae
• ISSN: 1534-5807; 1878-1551
• DOI: 10.1016/j.devcel.2007.01.016

Formation of syncytial muscle fibers involves repeated rounds of cell fusion between growing myotubes and neighboring myoblasts. We have established that Wsp, the
Drosophila homolog of the WASp family of microfilament nucleation-promoting factors, is an essential facilitator of myoblast fusion in
Drosophila embryos. D-WIP, a homolog of the conserved Verprolin/WASp Interacting Protein family of WASp-binding proteins, performs a key mediating role in this context. D-WIP, which is expressed specifically in myoblasts, associates with both the WASp-Arp2/3 system and with the myoblast adhesion molecules Dumbfounded and Sticks and Stones, thereby recruiting the actin-polymerization machinery to sites of myoblast attachment and fusion. Our analysis demonstrates that this recruitment is normally required late in the fusion process, for enlargement of nascent fusion pores and breakdown of the apposed cell membranes. These observations identify cellular and developmental roles for the WASp-Arp2/3 pathway, and provide a link between force-generating actin polymerization and cell fusion.