GNAT1 Gene: Guanine Nucleotide-Binding Protein G(t) Subunit Alpha-1
Key regulator of phototransduction in retinal rod cells; mutations cause congenital stationary night blindness
Gene Information Card
| Symbol | GNAT1 |
|---|---|
| Full Name | G protein subunit alpha transducin 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 3p21.31 |
| NCBI Gene ID | 2779 ncbi.nlm.nih.gov/gene/2779 |
| Ensembl ID | ENSG00000141480 |
| UniProt ID | P11488 |
| OMIM ID | 139330 |
| HGNC ID | 4393 |
| Aliases | GNAT1, Gt-alpha, GNA1, transducin alpha-1 |
Description
The GNAT1 gene encodes the alpha subunit of the heterotrimeric G protein transducin, which is specifically expressed in retinal rod photoreceptor cells. Transducin mediates the phototransduction cascade by coupling light-activated rhodopsin to cGMP phosphodiesterase, leading to hyperpolarization of the rod cell. Mutations in GNAT1 are associated with autosomal dominant and recessive forms of congenital stationary night blindness (CSNB) and, rarely, with other retinal dystrophies.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital stationary night blindness (CSNB), type 1D (autosomal dominant) | Dominant-negative or gain-of-function mutations impair transducin inactivation, causing persistent activation of the phototransduction cascade and desensitization of rod cells. | OMIM #613216; ClinVar |
| Congenital stationary night blindness (CSNB), type 1G (autosomal recessive) | Loss-of-function mutations reduce or abolish transducin activity, disrupting phototransduction and rod function. | OMIM #616389; ClinVar |
| Retinitis pigmentosa (rare association) | Some GNAT1 missense variants may lead to progressive rod degeneration, though evidence is limited. | ClinVar; literature case reports |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 45.2 | High |
| Testis | 0.3 | Low |
| Brain | 0.1 | Not detected |
| Heart | 0.0 | Not detected |
| Liver | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| ARPE-19 (retinal pigment epithelium) | 0.0 | Not expressed |
| Y79 (retinoblastoma) | 12.5 | Moderate expression (rod-like phenotype) |
| HEK293 | 0.0 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.113G>A (p.Gly38Asp) | Missense | Rare | Dominant-negative; impairs GTP hydrolysis, causing constitutive activation of transducin and CSNB |
| c.347C>T (p.Thr116Met) | Missense | Rare | Dominant-negative; reduces transducin inactivation, associated with CSNB |
| c.56G>A (p.Trp19*) | Nonsense | Rare | Loss-of-function; truncates protein, causes recessive CSNB |
| c.98delC (p.Pro33Leufs*2) | Frameshift | Rare | Loss-of-function; leads to premature stop, recessive CSNB |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations (e.g., p.Trp19*, p.Pro33Leufs*2) that truncate the protein or prevent proper folding, leading to recessive congenital stationary night blindness.
Gain of Function (GOF)
Not clearly documented; dominant mutations are typically dominant-negative rather than gain-of-function.
Dominant Negative (DN)
Missense mutations such as p.Gly38Asp and p.Thr116Met that impair GTP hydrolysis or disrupt normal transducin inactivation, causing persistent signaling and autosomal dominant CSNB.
View complete mutation data：
Gene Ontology (GO)
| • G protein activity (GO:0003925) | • signal transducer activity (GO:0004871) |
| • G protein-coupled receptor signaling pathway (GO:0007186) | • phototransduction (GO:0007602) |
| • detection of light stimulus (GO:0009583) | • integral component of membrane (GO:0016021) |
| • G protein beta/gamma-subunit complex binding (GO:0031683) |
Pathways
• Phototransduction cascade (KEGG: hsa04744)
• G alpha (s) signaling events (Reactome: R-HSA-418555)
• Visual signal transduction (Reactome: R-HSA-2188538)
Protein Summary
The GNAT1 protein (transducin alpha-1) is a 350-amino-acid G protein alpha subunit that binds GTP and activates cGMP phosphodiesterase in rod photoreceptors. It is anchored to the disc membrane via lipid modifications and interacts with rhodopsin and the beta/gamma subunits. The protein is essential for the rapid amplification of the light signal in the retina.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GNAT1 Knockout HEK293 Cell Line | EDJ-KQ4733 | Human | 2779 | Details Get a Quote |
| GNAT1 Knockout HeLa Cell Line | EDJ-KQ53366 | Human | 2779 | Details Get a Quote |
| GNAT1 Knockout A-549 Cell Line | EDJ-KQ61843 | Human | 2779 | Details Get a Quote |
| GNAT1 Knockout HCT 116 Cell Line | EDJ-KQ70328 | Human | 2779 | Details Get a Quote |
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