Acts as a nucleation-promoting factor by activating the Arp2/3 complex to induce actin polymerization (PubMed:19633175). Participates in both linear- and branched-actin networks (PubMed:19633175). Functions in linear-filament (bundled F-actin) by acting downstream of Rho1 and regulating actin and microtubule organization during oogenesis (PubMed:19633175). Nucleates actin in an Arp2/3-dependent manner and exhibits F-actin and microtubule bundling and cross-linking activity in the egg chamber (PubMed:19633175). During embryogenesis, acts downstream of Rho1 to activate the Arp2/3 complex which is necessary for the developmental migration of tail hemocytes anteriorly along the ventral midline (PubMed:25739458). Its function in hemocyte transmigration is independent of the WASH complex (PubMed:25739458). May play a role in endosomal sorting; its assembly in the WASH complex may regulate its nucleation-promoting factor (NPF) activity. Component of the WASH complex (PubMed:20498093). Interacts with spir and capu (PubMed:19633175). Interacts (via N-terminus) with Rho1 (via N-terminus) (PubMed:25739458). Lethal. Larvae die at the transition from third larval instar to prepupal stage. Belongs to the WASH1 family.