Role of myosin-II phosphorylation in V12Cdc42-mediated disruption of Drosophila cellularization

Janice M. Crawford, Zuowei Su, Olga Varlamova, Anne R. Bresnick, Daniel P. Kiehart

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Microinjection of constitutively active Cdc42 (V12Cdc42) disrupts the actomyosin cytoskeleton during cellularization (Crawford et al., Dev. Biol., 204, 151-164 (1998)). The p21-activated kinase (PAK) family of Ser/Thr kinases are effectors of GTP-bound forms of the small GTPases, Cdc42 and Rac. Drosophila PAK, which colocalizes with actin and myosin-II during cellularization, concentrates at sites of V12Cdc42-induced actomyosin disruption. In vitro biochemical analyses demonstrate that PAK phosphorylates the regulatory light chain (RLC) of Drosophila nonmuscle myosin-II on Ser21, a site known to activate myosin-II function. Although activated PAK does not disrupt the actomyosin cytoskeleton, it induces increased levels of Ser21 phosphorylated RLC. These findings suggest that increased levels of RLC phosphorylation do not contribute to disruption of the actomyosin hexagonal array.

Original languageEnglish (US)
Pages (from-to)240-244
Number of pages5
JournalEuropean Journal of Cell Biology
Issue number3
StatePublished - 2001


  • Actomyosin array
  • Cellularization
  • Drosophila
  • Myosin light chain kinase
  • P21-activated kinase
  • Regulatory light chain

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology


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