Extending the Arp2/3 complex and its regulation beyond the leading edge.

Two studies characterizing Drosophila Arp2/3 complex and Scar mutants demonstrate that assembly of some actin structures in nonmotile cells of multicellular organisms utilizes the same proteins as are important for actin assembly in motile cells. These studies also show that assembly of other actin structures is independent of these proteins, suggesting that alternative mechanisms also exist.