Involved in retrograde signaling from post-synaptic cells to pre-synaptic neurons, probably by regulating vesicle exocytosis in post-synaptic cells (PubMed:11804572, PubMed:2323555, PubMed:19028454). Acts in muscles, to regulate the localization of synaptic vesicle fusion protein unc-13 likely during vesicle exocytosis and thus regulate retrograde signaling at the neuromuscular junction (NMJ) (PubMed:11804572). Regulates anterior body muscle contractions (aBOC) and the expulsion steps during the defecation motor program (DMP) (PubMed:11804572, PubMed:2323555, PubMed:19028454). Probably by regulating DMP, plays a homeostatic role in the uptake of triglycerides (PubMed:25849533). Regulates locomotion (PubMed:11804572). Expressed in intestine, body wall muscles and some amphid neurons. Severely constipated due to absent or weak anterior body muscle (aBOC) and intestinal contractions during the defecation cycle (PubMed:11804572, PubMed:2323555). Reduced uptake and accumulation of triglycerides (PubMed:25849533). Locomotion defects characterized by mild body thrashing (PubMed:11804572). Partially resistant to paralysis induced by acetylcholine esterase inhibitor aldicarb (PubMed:2323555, PubMed:19028454). Reduced enrichment of unc-13 at presynaptic active sites of neuromuscular junctions (PubMed:11804572). Belongs to the unc-13 family.