Wiskott-Aldrich syndrome protein family member 1 is a protein that in humans is encoded by the WASF1 gene.

The protein encoded by this gene, a member of the Wiskott-Aldrich syndrome protein (WASP)-family, plays a critical role downstream of Rac, a Rho-family small GTPase, in regulating the actin cytoskeleton required for membrane ruffling. It has been shown to associate with an actin nucleation core Arp2/3 complex while enhancing actin polymerization in vitro. Wiskott-Aldrich syndrome is a disease of the immune system, likely due to defects in regulation of actin cytoskeleton. Multiple alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq].
Function: Downstream effector molecules involved in the transmission of signals from tyrosine kinase receptors and small GTPases to the actin cytoskeleton.