Myosin II-dependent exclusion of CD45 from the site of Fcγ receptor activation during phagocytosis

Fc gamma receptor (Fc gamma R)-mediated phagocytosis requires myosin H activity. Here we show that myosin 11 contributes to Fc gamma R activation and subsequent F-actin assembly at the nascent phagocytic cup. Inhibition of myosin II attenuates phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM) of Fc gamma R and binding of Syk to the ITAM. Furthermore, Fc gamma R clusters independently of myosin II activity at the phagocytic cup, from which the receptor-like protein tyrosine phosphatase CD45 is excluded depending on myosin II activity. These findings suggest that myosin II-dependent segregation of CD45 from Fc gamma R facilitates phosphorylation of the ITAM and triggers phagocytosis. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.