Fig. 7. Models for the redundancy of Rac function in axon pathfinding, cell migration, and cell-corpse phagocytosis. Boxes indicate a required gene and broken arrows indicate a subtle function. (A) mig-2 Rac-like, ced-10 Rac and rac-2/3 Rac act redundantly in CAN axon pathfinding and cell migration. unc-73 Trio acts in all three pathways. ced-5 DOCK180, which acts in parallel with ced-10 Rac, might act with mig-2 Rac-like, rac-2/3 Rac or both (indicated by parentheses). ced-2 CrkII is not involved in CAN axon pathfinding. (B) mig-2 Rac-like, ced-10 Rac and rac-2/3 Rac act redundantly in CAN cell migration. mig-2 Rac-like and ced-10 Rac are both necessary for DTC migration and are regulated by unc-73 Trio, ced-2 CrkII and ced-5 DOCK180. rac-2/3 Rac is not necessary for DTC migration and is not shown here. rac-2/3 Rac is slightly redundant for cell movement with mig-2 but not ced-10. (C) ced-10 Rac is the primary rac involved in phagocytosis, whereas rac-2/3 Rac and mig-2 Rac-like have subtle functions seen only in genetically sensitized backgrounds. unc-73 Trio is not involved in phagocytosis.
