GNAT3 (G Protein Subunit Alpha Transducin 3)
Gustducin Alpha Subunit: A Key Mediator of Bitter, Sweet, and Umami Taste Transduction
Gene Information Card
| Symbol | GNAT3 |
|---|---|
| Full Name | G Protein Subunit Alpha Transducin 3 |
| Gene Type | protein-coding |
| Chromosomal Location | 7q21.11 |
| NCBI Gene ID | 346562 ncbi.nlm.nih.gov/gene/346562 |
| Ensembl ID | ENSG00000189221 |
| UniProt ID | P59768 |
| OMIM ID | 139080 |
| HGNC ID | 4380 |
| Aliases | Gustducin, Galpha-gustducin, GDCA |
Description
GNAT3 encodes the alpha subunit of the heterotrimeric G protein gustducin, which is primarily expressed in taste receptor cells of the tongue and palate. Gustducin mediates signal transduction from sweet, bitter, and umami taste receptors (T1R and T2R families) by activating downstream effectors such as phosphodiesterase and phospholipase C. This gene plays a critical role in taste perception and has been implicated in metabolic regulation and dietary preferences.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Type 2 Diabetes | Altered GNAT3 expression may affect taste sensitivity to sweet compounds, influencing glucose homeostasis and insulin secretion. | PMID: 25664888 |
| Obesity | Polymorphisms in GNAT3 are associated with reduced taste sensitivity to sweet and fat, potentially leading to increased caloric intake. | PMID: 23134865 |
| Taste Dysfunction (Ageusia/Hypogeusia) | Loss-of-function mutations in GNAT3 impair gustducin signaling, reducing perception of bitter, sweet, and umami tastes. | PMID: 12508121 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Tongue (taste buds) | 12.5 | High |
| Small intestine | 3.2 | Low |
| Pancreas | 2.1 | Low |
| Testis | 1.8 | Low |
| Brain (cerebellum) | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Taste bud cells (type II) | 15.0 | Primary taste receptor cells |
| HCT-116 (colon cancer) | 0.8 | Low expression |
| HEK-293 | 0.2 | Minimal expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.101C>T (p.Thr34Met) | Missense | 0.01% | Reduced GTP binding affinity; associated with hypogeusia |
| c.245G>A (p.Arg82His) | Missense | 0.005% | Impaired receptor coupling; reported in taste dysfunction |
| c.457C>T (p.Arg153*) | Nonsense | <0.001% | Premature stop; loss of function; rare |
Mutation functional classification
Loss of Function (LOF)
Missense and nonsense mutations that disrupt GTP binding, receptor coupling, or protein stability lead to reduced or absent gustducin activity, impairing taste transduction.
Gain of Function (GOF)
No gain-of-function mutations have been reported for GNAT3.
Dominant Negative (DN)
No dominant-negative mutations have been characterized for GNAT3.
View complete mutation data：
Gene Ontology (GO)
| • G protein-coupled receptor signaling pathway | • sensory perception of taste |
| • signal transduction | • GTP binding |
| • GTPase activity | • heterotrimeric G-protein complex |
| • plasma membrane |
Pathways
• Taste transduction (KEGG: hsa04742)
• GPCR downstream signaling (Reactome: R-HSA-416476)
Protein Summary
Gustducin alpha subunit (GNAT3) is a 354-amino acid G protein alpha subunit that couples taste receptors to intracellular signaling cascades. It shares structural homology with transducin (GNAT1/GNAT2) but is uniquely expressed in taste buds. Upon receptor activation, GNAT3 exchanges GDP for GTP, dissociates from beta-gamma subunits, and activates phosphodiesterase to reduce cAMP levels, ultimately leading to neurotransmitter release and taste perception.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GNAT3 Knockout HEK293 Cell Line | EDJ-KQ12861 | Human | 346562 | Details Get a Quote |
| GNAT3 Knockout HeLa Cell Line | EDJ-KQ59802 | Human | 346562 | Details Get a Quote |
| GNAT3 Knockout A-549 Cell Line | EDJ-KQ68270 | Human | 346562 | Details Get a Quote |
| GNAT3 Knockout HCT 116 Cell Line | EDJ-KQ76645 | Human | 346562 | Details Get a Quote |
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