GNAT1

Transducin is a 3-subunit guanine nucleotide-binding protein (G protein) which stimulates the coupling of rhodopsin and cGMP-phoshodiesterase during visual impulses. The transducin alpha subunits in rods and cones are encoded by separate genes. This gene encodes the alpha subunit in rods. This gene is also expressed in other cells, and has been implicated in bitter taste transduction in rat taste cells. Mutations in this gene result in autosomal dominant congenital stationary night blindness. Multiple alternatively spliced variants, encoding the same protein, have been identified.

Full Name

G protein subunit alpha transducin 1

Function

Functions as signal transducer for the rod photoreceptor RHO. Required for normal RHO-mediated light perception by the retina (PubMed:22190596).

Guanine nucleotide-binding proteins (G proteins) function as transducers downstream of G protein-coupled receptors (GPCRs), such as the photoreceptor RHO. The alpha chain contains the guanine nucleotide binding site and alternates between an active, GTP-bound state and an inactive, GDP-bound state. Activated RHO promotes GDP release and GTP binding. Signaling is mediated via downstream effector proteins, such as cGMP-phosphodiesterase (By similarity).

Biological Process

Adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway Source: GO_Central
Adenylate cyclase-modulating G protein-coupled receptor signaling pathway Source: GO_Central
Cell population proliferation Source: Ensembl
Cellular response to electrical stimulus Source: Ensembl
Detection of chemical stimulus involved in sensory perception of bitter taste Source: Ensembl
Detection of light stimulus involved in visual perception Source: UniProtKB
Eye photoreceptor cell development Source: Ensembl
G protein-coupled adenosine receptor signaling pathway Source: GO_Central
Negative regulation of cyclic-nucleotide phosphodiesterase activity Source: UniProtKB
Phototransduction, visible light Source: UniProtKB
Positive regulation of cyclic-nucleotide phosphodiesterase activity Source: Ensembl
Regulation of rhodopsin mediated signaling pathway Source: Reactome
Response to light intensity Source: Ensembl
Response to light stimulus Source: UniProtKB
Retina development in camera-type eye Source: Ensembl
Rhodopsin mediated signaling pathway Source: Ensembl
Sensory perception of umami taste Source: Ensembl
Signal transduction Source: UniProtKB
Visual perception Source: UniProtKB

Cellular Location

Photoreceptor outer segment; Membrane; Photoreceptor inner segment. Localizes mainly in the outer segment in the dark-adapted state, whereas is translocated to the inner part of the photoreceptors in the light-adapted state. During dark-adapted conditions, in the presence of UNC119 mislocalizes from the outer segment to the inner part of rod photoreceptors which leads to decreased photoreceptor damage caused by light.

Involvement in disease

Night blindness, congenital stationary, autosomal dominant 3 (CSNBAD3):
A non-progressive retinal disorder characterized by impaired night vision, often associated with nystagmus and myopia.
Night blindness, congenital stationary, 1G (CSNB1G):
An autosomal recessive form of congenital stationary night blindness, a non-progressive retinal disorder characterized by impaired night vision or in dim light, with good vision only on bright days.