Visual signal transduction is mediated by a G-protein coupled cascade using cGMP as second messenger. This protein can be activated by cGMP which leads to an opening of the cation channel and thereby causing a depolarization of rod 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 efficiency of the channel when coexpressed with CNGA3 (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. Expressed specifically in the retina. The disease is caused by variants affecting the gene represented in this entry. 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. CNGB3 subfamily. Truncated N-terminus.