This family is the central, conserved region of proteins that form subunit 7 of the WASH complex [1]. In species such as Drosophila this protein is the only component of the 'complex'. This complex is a nucleation promoting factor necessary for the activation of Arp2/3 that nucleates and organises actin filaments by associating with a pre-existing filament to induce the assembly of a branching filament. WASH thus effectively nucleates actin on endosomes [2].

1: The Arp2/3 activator WASH controls the fission of endosomes through a large multiprotein complex. Derivery E, Sousa C, Gautier JJ, Lombard B, Loew D, Gautreau A; Dev Cell. 2009;17:712-723. PMID:19922875

2: WASH, WHAMM and JMY: regulation of Arp2/3 complex and beyond. Rottner K, Hanisch J, Campellone KG; Trends Cell Biol. 2010;20:650-661. PMID:20888769