Research ArticleCell Biology

Myosin I Links PIP3 Signaling to Remodeling of the Actin Cytoskeleton in Chemotaxis

Sci. Signal.  31 Jan 2012:
Vol. 5, Issue 209, pp. ra10
DOI: 10.1126/scisignal.2002446

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Linking Membrane Lipids to Cytoskeletal Dynamics

The phospholipid PIP3 (phosphatidylinositol 3,4,5-trisphosphate) can be generated at the plasma membrane in cells orienting their movement according to an external chemical gradient (a process called chemotaxis) or in cells engulfing particles or other cells (a process called phagocytosis). Both chemotaxis and phagocytosis require reorganization of the cytoskeleton. Various type I myosin isoforms (specifically, ID, IE, and IF) are motor proteins that interact with the actin cytoskeleton as PIP3-binding proteins. Here, Chen et al. showed that myosins ID, IE, and IF were required for PIP3-induced changes in the cytoskeleton. Dictyostelium cells lacking these three myosin I isoforms showed defects in chemotaxis and in phagocytosis of yeast cells. Furthermore, these mutant Dictyostelium cells failed to remodel the cytoskeleton in response to a chemoattractant. Thus, specific myosin I isoforms couple stimuli that generate PIP3 to changes in the cytoskeleton during chemotaxis and phagocytosis.