Required in engulfing to control the phagocytosis of apoptotic cell corpses (PubMed:10707082, PubMed:20126385). Required in embryonic development for the correct positioning and orientation of the mitotic spindles and division planes in blastomere cells (PubMed:20126385). Involved in hypodermal cell fusion, together with pak-1 and cdc-42, leading to embryonic body elongation, which involves dramatic cytoskeletal reorganization (PubMed:8824291). ced-2 and ced-5 function to activate ced-10 in a GTPase signaling pathway that controls the polarized extension of cell surfaces (PubMed:10707082). Plays a redundant role with mig-2 in dorsal axonal guidance in ventral cord commissural motoneurons and in P neuroblast migration. May regulate these 2 processes by activating pak-1 and/or max-2 (PubMed:17050621). Plays a role, probably via mig-10, in orientating axonal growth of HSN and AVM neurons in response to guidance cues such as slt-1. Regulates mig-10 asymmetric distribution in HSN neurons (PubMed:18499456). During the dorso-ventral axonal guidance and outgrowth of VD neurons, required together with mig-2 to inhibit growth cone filopodial protrusion mediated by netrin guidance cue unc-6 and its receptors unc-5 and unc-40 (PubMed:25371370, PubMed:30045855). Specifically, regulates growth cone filopodial protrusion polarity, and thus migration, by promoting F-actin polarization and, together with mig-2, by restricting plus-end microtubule accumulation in the growth cone (PubMed:30045855). Plays a role in protecting dopaminergic neurons from oxidative stress-induced degeneration (PubMed:29346382). During gonad morphogenesis, plays a role in distal tip cell (DTC)-mediated guidance of gonad elongation, probably by activating max-2 (PubMed:19797046, PubMed:19023419). Furthermore, plays a role in distal tip cell polarity and migration by negatively regulating the unc-6/Netrin receptor unc-5 (PubMed:26292279). May be involved in signal transduction during cell migration (PubMed:10707082). May be involved in the positioning of ray 1, the most anterior ray sensilium, in the male tail (PubMed:24004945). Interacts (GTP-bound form) with pak-1 (PubMed:8824291). May interact (GTP-bound form) with mig-10 (via Ras-associating and PH domains) (PubMed:18499456). Co-localizes with pak-1 and cdc-42 at hypodermal cell boundaries during embryo elongation. Colocalizes with pak-1 to hypodermal cell boundaries during embryo elongation throughout the second phase of embryogenesis. Most abundant at embryonic stage, its expression decreases dramatically during development. In the second generation, there is defective mitotic spindle orientation in the EMS and ABar blastomeres which results in disrupted left-right asymmetry and failure to undergo morphogenesis (PubMed:20126385). Due to defective apoptotic cell clearance, embryos accumulate apoptotic cell corpses (PubMed:20126385). Distal tip cell migratory defects (PubMed:26292279). Double knockout with unc-5 RNAi suppresses the distal tip cell migratory defect in the ced-10 single mutant (PubMed:26292279). Belongs to the small GTPase superfamily. Rho family.