Wiskott-Aldrich syndrome protein is necessary for efficient IgG-mediated phagocytosis

Interactions between the Wiskott-Aldrich (WAS) protein (WASp), small GTPase s, and the cytoskeletal organizing complex Arp2/3 appear to be critical for the transduction of signals from the cell membrane to the actin cytoskelet on in hematopoietic cells, This study shows that Fc gamma-receptor (Fc gamm a R)-mediated phagocytosis is impaired in WASp-deficient peripheral blood m onocytes, and that in macrophages, formation of the actin cup and local rec ruitment of tyrosine phosphorylated proteins is markedly attenuated. Result s also show that, in normal macrophages, WASp itself is actively recruited to the cup, suggesting that assembly of this specialized cytoskeletal struc ture is dependent on its expression. (Blood. 2000;95:2943-2946) (C) 2000 by The American Society of Hematology.