Effector protein for Rho-type GTPases that regulates actin filament reorganization via its interaction with the Arp2/3 complex (PubMed:12235133, PubMed:12769847, PubMed:16275905). Important for efficient actin polymerization (PubMed:8625410, PubMed:12235133, PubMed:16275905). Possible regulator of lymphocyte and platelet function (PubMed:9405671). Mediates actin filament reorganization and the formation of actin pedestals upon infection by pathogenic bacteria (PubMed:18650809). In addition to its role in the cytoplasmic cytoskeleton, also promotes actin polymerization in the nucleus, thereby regulating gene transcription and repair of damaged DNA (PubMed:20574068). Promotes homologous recombination (HR) repair in response to DNA damage by promoting nuclear actin polymerization, leading to drive motility of double-strand breaks (DSBs) (PubMed:29925947). Binds the Arp2/3 complex (PubMed:12769847). Interacts with CDC42, RAC, NCK, HCK, FYN, SRC kinase FGR, BTK, ABL1, PSTPIP1, WIP, and to the p85 subunit of PLC-gamma (PubMed:8643625, PubMed:9405671, PubMed:12235133, PubMed:10360578, PubMed:15235593). Interacts (via C-terminus) with ALDOA (PubMed:17329259). Interacts with NCK1 (via SH3 domains) (By similarity). Interacts with FCHSD2 (By similarity). (Microbial infection) Interacts with E.coli effector protein EspF(U). Expressed predominantly in the thymus. Also found, to a much lesser extent, in the spleen. The WH1 (Wasp homology 1) domain may bind a Pro-rich ligand. The CRIB (Cdc42/Rac-interactive-binding) region binds to the C-terminal WH2 domain in the autoinhibited state of the protein. Binding of Rho-type GTPases to the CRIB induces a conformation change and leads to activation. Phosphorylated at Tyr-291 by FYN and HCK, inducing WAS effector activity after TCR engagement. Phosphorylation at Tyr-291 enhances WAS activity in promoting actin polymerization and filopodia formation. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Extended N-terminus. WAS mutation db WAS mutation db Wiskott-Aldrich syndrome protein entry