UniProt Summary: Guanine nucleotide-binding protein (G protein) alpha subunit playing a prominent role in bitter and sweet taste transduction as well as in umami (monosodium glutamate, monopotassium glutamate, and inosine monophosphate) taste transduction. Transduction by this alpha subunit involves coupling of specific cell-surface receptors with a cGMP-phosphodiesterase; Activation of phosphodiesterase lowers intracellular levels of cAMP and cGMP which may open a cyclic nucleotide-suppressible cation channel leading to influx of calcium, ultimately leading to release of neurotransmitter. Indeed, denatonium and strychnine induce transient reduction in cAMP and cGMP in taste tissue, whereas this decrease is inhibited by GNAT3 antibody. Gustducin heterotrimer transduces response to bitter and sweet compounds via regulation of phosphodiesterase for alpha subunit, as well as via activation of phospholipase C for beta and gamma subunits, with ultimate increase inositol trisphosphate and increase of intracellular Calcium. GNAT3 can functionally couple to taste receptors to transmit intracellular signal: receptor heterodimer TAS1R2/TAS1R3 senses sweetness and TAS1R1/TAS1R3 transduces umami taste, whereas the T2R family GPCRs act as bitter sensors. Functions also as lumenal sugar sensors in the gut to control the expression of the Na+-glucose transporter SGLT1 in response to dietaty sugar, as well as the secretion of Glucagon-like peptide- 1, GLP-1 and glucose-dependent insulinotropic polypeptide, GIP. Thus, may modulate the gut capacity to absorb sugars, with implications in malabsorption syndromes and diet-related disorders including diabetes and obesity. {ECO:0000269|PubMed:11917125, ECO:0000269|PubMed:17724330}.
Pfam DomainsGO Terms
Pfam Domains
Arf
G-alpha
GO Terms
sensory perception of umami taste
sensory perception of sweet taste
G-protein beta/gamma-subunit complex binding
heterotrimeric G-protein complex
detection of chemical stimulus involved in sensory perception of bitter taste
sensory perception of bitter taste
detection of chemical stimulus involved in sensory perception of taste
photoreceptor inner segment
response to nicotine
photoreceptor outer segment
G protein-coupled receptor binding
sensory perception of taste
adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway
acrosomal vesicle
axoneme
adenylate cyclase-modulating G protein-coupled receptor signaling pathway
protein folding
G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger
apical plasma membrane
GTPase activity
GTP binding
detection of chemical stimulus involved in sensory perception
response to toxic substance
detection of chemical stimulus
sensory perception of chemical stimulus
detection of stimulus involved in sensory perception
protein-containing complex
detection of stimulus
sensory perception
response to drug
G protein-coupled receptor signaling pathway
nervous system process
system process
CRISPR Data
Compound HitMost Correlated Genes in ChemogenomicsTissues where Essential in the Avana Dataset (DepMap 20Q1)
Compound Hit
No hits were found.
Most Correlated Genes in Chemogenomics
No correlation found to any other genes in chemogenomics.
Tissues where Essential in the Avana Dataset (DepMap 20Q1)
Global Fraction of Cell Lines Where Essential: 0/739