| | Structured_description | Concise_description | ric-8 encodes a receptor-independent G alpha guanine nucleotide exchange factor (GEF); ric-8 activity is required for regulating heterotrimeric G protein signaling pathways that control asymmetric cell division in the embryo as well as synaptic transmission in the nervous system; in the 1-cell embryo, RIC-8 functions as a GEF for GOA-1 thereby regulating spindle morphology, position, and consequently, the first asymmetric cell division; in the nervous system, RIC-8 likely functions to regulate activity of both the EGL-30 and GSA-1 pathways to regulate neurotransmitter secretion and thus, coordinated locomotion; RIC-8 also functions, with AGS-3, to activate GOA-1/Galpha0 in the ASH chemosensory neurons to modulate behavior after food deprivation; in vitro, RIC-8 preferentially binds GOA-1-GDP and increases the rate of GOA-1 GTP binding; in the early embryo, RIC-8 localizes to the cellular cortex, junctions between cells, asters of the mitotic spindle, the central spindle (kinetochore microtubules), the nuclear envelope, and chromatin; RIC-8's localization to the cortex and asters mirrors that of GOA-1, while localization to the cortex and central spindle is similar to that of the GOA-1 regulators GPR-1/2, whose subcellular localization is RIC-8-dependent; in later stage animals, RIC-8 is seen in head and tail ganglia, amphid processes, and the ventral nerve cord, as well as in larval nonneuronal cells, such as germline nuclei, where it localizes near the nuclear membrane. | Paper_evidence | WBPaper00002590 |