Cyclic Nucleotide Gated Channel Alpha 1 (CNGa1)

Phototransduction is mediated by an enzymatic cascade that ultimately leads to the hydrolysis of cGMP. The photoreceptor cells, rods and cones, integrate and respond to cGMP hydrolysis via a cGMP-gated cation channel in the plasma membrane of the outer segment.The open reading frames predicted polypeptides of 690 and 683 residues, respectively, exhibiting 88% sequence similarity. Significant sequence similarity (59%) of the visual cGMP-gated channel to the olfactory cAMP-gated channel was pointed out. The RNA transcript was found to be 3.2 kb long in human, mouse, and dog.The retinal rod cGMP-gated cation channel is a hetero-oligomer composed of 2 homologous subunits, alpha (CNCG1) and beta (CNCG2), each with cytoplasmic N and C termini, 6 putative transmembrane domains, and a pore region.