C. elegans CED-12 acts in the conserved crkII/DOCK180/Rac pathway to control cell migration and cell corpse engulfment.

We have identified and characterized a novel C. elegans gene, ced-12, that functions in the conserved GTPase signaling pathway mediated by CED-2/Crkll, CED-5/DOCK180, and CED-10/Rac to control cell migration and phagocytosis of apoptotic cells. We provide evidence that ced-12 likely acts upstream of ced-10 during cell migration and phagocytosis and that CED-12 physically interacts with CED-5 and forms a ternary complex with CED-2 in vitro. We propose that the formation and localization of a CED-2-CED-5-CED-12 ternary complex to the plasma membrane activates CED-10, leading to the cytoskeletal reorganization that occurs in the polarized extension of cell surfaces in engulfing cells and migrating cells. We suggest that CED-12 counterparts in higher organisms regulate cytoskeleton dynamics, as CED-12 does in C. elegans.