Rac regulates phosphorylation of the myosin-II heavy chain, actinomyosin disassembly and cell spread
Author: ["Frank N. van Leeuwen","Sanne van Delft","Hendrie E. Kain","Rob A. van der Kammen","John G. Collard"]
Publication: Nature Cell Biology
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Abstract
GTPases of the Rho family regulate actinomyosin-based contraction in non-muscle cells. Activation of Rho increases contractility, leading to cell rounding and neurite retraction in neuronal cell lines. Activation of Rac promotes cell spreading and interferes with Rho-mediated cell rounding. Here we show that activation of Rac may antagonize Rho by regulating phosphorylation of the myosin-II heavy chain. Stimulation of PC12 cells or N1E-115 neuroblastoma cells with bradykinin induces phosphorylation of threonine residues in the myosin-II heavy chain; this phosphorylation is Ca2+ dependent and regulated by Rac. Both bradykinin-mediated and constitutive activation of Rac promote cell spreading, accompanied by a loss of cortical myosin II. Our results identify the myosin-II heavy chain as a new target of Rac-regulated kinase pathways, and implicate Rac as a Rho antagonist during myosin-II-dependent cell-shape changes.
Cite this article
van Leeuwen, F., van Delft, S., Kain, H. et al. Rac regulates phosphorylation of the myosin-II heavy chain, actinomyosin disassembly and cell spreading. Nat Cell Biol 1, 242–248 (1999). https://doi.org/10.1038/12068
