GNAT2: Guanine Nucleotide-Binding Protein G(t) Subunit Alpha-2
Key component of cone phototransduction; mutations cause achromatopsia
Gene Information Card
| Symbol | GNAT2 |
|---|---|
| Full Name | G protein subunit alpha transducin 2 |
| Gene Type | protein-coding |
| Chromosomal Location | 1p13.3 |
| NCBI Gene ID | 2780 ncbi.nlm.nih.gov/gene/2780 |
| Ensembl ID | ENSG00000166840 |
| UniProt ID | P19087 |
| OMIM ID | 139340 |
| HGNC ID | 4394 |
| Aliases | ACHM4, GNATC, GNT2 |
Description
GNAT2 encodes the alpha subunit of cone-specific transducin, a heterotrimeric G protein that couples photoisomerized cone opsins to cGMP phosphodiesterase in cone photoreceptors. It is essential for color vision and high-acuity daylight vision. Loss-of-function mutations cause autosomal recessive achromatopsia type 4 (ACHM4).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Achromatopsia 4 (ACHM4) | Loss-of-function mutations in GNAT2 disrupt cone phototransduction, leading to absent cone responses | ClinVar, OMIM |
| Cone dystrophy | Rare missense variants may impair transducin activation, causing progressive cone degeneration | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 12.5 | High |
| Testis | 0.3 | Low |
| Brain | 0.1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| ARPE-19 | 0.0 | Not expressed |
| Y79 retinoblastoma | 8.2 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.461G>A (p.Trp154*) | Nonsense | Rare (MAF <0.01%) | Premature stop; loss of function |
| c.802C>T (p.Arg268Cys) | Missense | Rare | Impaired GTP binding; reduced transducin activity |
| c.1000C>T (p.Arg334Trp) | Missense | Rare | Disrupted receptor coupling; loss of function |
Mutation functional classification
Loss of Function (LOF)
Majority of pathogenic GNAT2 variants are loss-of-function (nonsense, frameshift, splice-site) leading to truncated or absent protein.
Gain of Function (GOF)
No gain-of-function mutations reported in GNAT2.
Dominant Negative (DN)
No dominant-negative mutations reported; all pathogenic variants are recessive.
View complete mutation data：
Gene Ontology (GO)
| • G protein-coupled receptor signaling pathway | • phototransduction |
| • GTPase activity | • signal transducer activity |
| • heterotrimeric G-protein complex |
Pathways
• Phototransduction cascade (KEGG: hsa04744)
• G alpha (s) signaling events (Reactome: R-HSA-418555)
Protein Summary
GNAT2 encodes the 354-amino-acid alpha subunit of cone transducin (Gαt2). It binds GTP and activates cGMP phosphodiesterase in response to light-activated cone opsins. The protein is expressed exclusively in cone photoreceptors and is critical for color vision. Mutations cause achromatopsia type 4.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GNAT2 Knockout HEK293 Cell Line | EDJ-KQ4740 | Human | 2780 | Details Get a Quote |
| GNAT2 Knockout HeLa Cell Line | EDJ-KQ53367 | Human | 2780 | Details Get a Quote |
| GNAT2 Knockout A-549 Cell Line | EDJ-KQ61844 | Human | 2780 | Details Get a Quote |
| GNAT2 Knockout HCT 116 Cell Line | EDJ-KQ70329 | Human | 2780 | Details Get a Quote |
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