G Protein Alpha Transducing Activity Polypeptide 3 (GNaT3)

Gustducin mRNA was expressed in taste buds of papillae of all types; it was not expressed in nonsensory portions of the tongue or in the other tissues examined. Gustducin most closely resembles the transducins, i.e., the rod and cone photoreceptor G proteins, suggesting that gustducin's role in taste transduction is analogous to that of transducin in light transduction.

Mouse intestinal cells also expressed Gnat3, and ingestion of glucose by Gnat3-null mice revealed deficiencies in secretion of glucagon-like peptide-1 (GLP1) and the regulation of plasma insulin and glucose. Isolated small bowel and intestinal villi from Gnat3-null mice showed markedly defective GLP1 secretion in response to glucose.