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 cones. [provided by RefSeq, Jul 2008],disease:Defects in GNAT2 are the cause of achromatopsia type 4 (ACHM4) [MIM:139340]. Achromatopsia is an autosomal recessively inherited visual disorder that is present from birth and that features the absence of color discrimination.,function:Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. Transducin is an amplifier and one of the transducers of a visual impulse that performs the coupling between rhodopsin and cGMP-phosphodiesterase.,similarity:Belongs to the G-alpha family. G(i/o/t/z) subfamily.,subunit:G proteins are composed of 3 units, alpha, beta and gamma. The alpha chain contains the guanine nucleotide binding site.,tissue specificity:Retinal rod outer segment.,
