G Protein Alpha Transducing Activity Polypeptide 1 (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. GNAT1 encodes the alpha subunit in rods. Alternative splicing of this gene results in two transcript variants. The deduced 350-amino acid transducin protein, which is 100% identical to the mouse protein, contains a G-alpha domain and an ARF domain. Northern blot analysis revealed abundant expression of a 1.5-kb transcript in retina and fetal heart and in T-cell lines. No expression was detected in lung or lung cancer cell lines, and no mutations were found in any lung cancer cell lines.