Wiskott-Aldrich syndrome protein WASP is part of the WAS family of proteins that mediate cell signals that regulate the dynamics of the actin cytoskeleton. WASP associates with Cdc42, a Rho-family GTPase, and the cytoskeletal organizing complex, Arp2/3, to stimulate actin-polymerization. WASP also binds with RAC, NCK, FYN, SRC kinase FGR, BTK, ABL, PSTPIP1, WIP, and to the p85 subunit of PLC-gamma.