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zipper nonmuscle myosin-II functions downstream of PS2 integrin in Drosophila myogenesis and is necessary for myofibril formation
- Source :
- Developmental Biology. Nov 15, 2001, Vol. 239 Issue 2, p215, 14 p.
- Publication Year :
- 2001
-
Abstract
- Nonmuscle myosin-II is a key motor protein that drives cell shape change and cell movement. Here, we analyze the function of nonmuscle myosin-II during Drosophila embryonic myogenesis. We find that nonmuscle myosin-II and the adhesion molecule, PS2 integrin, colocalize at the developing muscle termini. In the paradigm emerging from cultured fibroblasts, nonmuscle actomyosin-II contractility, mediated by the small GTPase Rho, is required to cluster integrins at focal adhesions. In direct opposition to this model, we find that neither nonmuscle myosin-II nor RhoA appear to function in PS2 clustering. Instead, PS2 integrin is required for the maintenance of nonmuscle myosin-II localization and we show that the cytoplasmic tail of the [[beta].sub.PS] integrin subunit is capable of mediating this PS2 integrin function. We show that embryos that lack zygotic expression of nonmuscle myosin-II fail to form striated myofibrils. In keeping with this, we demonstrate that a PS2 mutant that specifically disrupts myofibril formation is unable to mediate proper localization of nonmuscle myosin-II at the muscle termini. In contrast, embryos that lack RhoA function do generate striated muscles. Finally, we find that nonmuscle myosin-II localizes to the Z-line in mature larval muscle. We suggest that nonmuscle myosin-II functions at the muscle termini and the Z-line as an actin crosslinker and acts to maintain the structural integrity of the sarcomere. Key Words: Drosophila; nonmuscle myosin-II; integrins; myofibrils; RhoA GTPase.
Details
- ISSN :
- 00121606
- Volume :
- 239
- Issue :
- 2
- Database :
- Gale General OneFile
- Journal :
- Developmental Biology
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.80744299