Visual signal transduction is mediated by a G-protein coupled cascade using cGMP as second messenger. This protein can be activated by cyclic GMP which leads to an opening of the cation channel and thereby causing a depolarization of cone photoreceptors. Induced a flickering channel gating, weakened the outward rectification in the presence of extracellular calcium, increased sensitivity for L-cis diltiazem and enhanced the cAMP efficacy of the channel when coexpressed with CNGB3 (By similarity). Essential for the generation of light-evoked electrical responses in the red-, green- and blue sensitive cones. Tetramer formed of three CNGA3 and one CNGB3 modulatory subunits. Prominently expressed in retina. The C-terminal coiled-coil domain mediates homotrimerization of CNGA subunits. The disease is caused by variants affecting the gene represented in this entry. Belongs to the cyclic nucleotide-gated cation channel (TC 1.A.1.5) family. CNGA3 subfamily. Retina International's Scientific Newsletter