Phosphorylation of myosin-II regulatory light chain by cyclin-p34(cdc2): A mechanism for the timing of cytokinesis

L. L. Satterwhite, M. J. Lohka, K. L. Wilson, T. Y. Scherson, L. J. Cisek, J. L. Corden, T. D. Pollard

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153 Scopus citations


To understand how cytokinesis is regulated during mitosis, we tested cyclin-p34(cdc2) for myosin-II kinase activity, and investigated the mitotic- specific phosphorylation of myosin-II in lysates of Xenopus eggs. Purified cyclin-p34(cdc2) phosphorylated the regulatory light chain of cytoplasmic and smooth muscle myosin-II in vitro on serine-1 or serine-2 and threonine-9, sites known to inhibit the actin-activated myosin ATPase activity of smooth muscle and nonmuscle myosin (Nishikawa, M., J. R. Sellers, R. S. Adelstein, and H. Hidaka. 1984. J. Biol. Chem. 259:8808-8814; Bengur, A. R., A. E. Robinson, E. Appella, and J. R. Sellers. 1987. J. Biol. Chem. 262:7613-7617; Ikebe, M., and S. Reardon. 1990. Biochemistry. 29:2713-2720). Serine-1 or -2 of the regulatory light chain of Xenopus cytoplasmic myosin-II was also phosphorylated in Xenopus egg lysates stabilized in metaphase, but not in interphase. Inhibition of myosin-II by cyclin-p34(cdc2) during prophase and metaphase could delay cytokinesis until chromosome segregation is initiated and thus determine the timing of cytokinesis relative to earlier events in mitosis.

Original languageEnglish (US)
Pages (from-to)595-605
Number of pages11
JournalJournal of Cell Biology
Issue number3
StatePublished - 1992

ASJC Scopus subject areas

  • Cell Biology


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