Plays a role in the reorganization of the actin cytoskeleton. Contributes with NCK1 and GRB2 in the recruitment and activation of WASL. May participate in regulating the subcellular localization of WASL, resulting in the disassembly of stress fibers in favor of filopodia formation. Plays a role in the formation of cell ruffles (By similarity). Plays an important role in the intracellular motility of vaccinia virus by functioning as an adapter for recruiting WASL to vaccinia virus. {ECO:0000250, ECO:0000269|PubMed:10878810, ECO:0000269|PubMed:19910490, ECO:0000269|PubMed:9405671}. This is the function of WIPF1 (WAS/WASL interacting protein family member 1, Ensembl gene identifier ENSG00000115935).