FunctionVisual 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.
Tissue specificityExpressed specifically in the retina.
Involvement in diseaseDefects in CNGB3 are the cause of Stargardt disease type 1 (STGD1) [MIM:248200]. STGD is one of the most frequent causes of macular degeneration in childhood. It is characterized by macular dystrophy with juvenile-onset, rapidly progressive course, alterations of the peripheral retina, and subretinal deposition of lipofuscin-like material. STGD1 inheritance is autosomal recessive. Defects in CNGB3 are the cause of achromatopsia type 3 (ACHM3) [MIM:262300]; also known as Pingelapese blindness. ACHM3 is a congenital complete achromatopsia and is distinct from total colorblindness mainly because of the consistent concurrence of severe myopia.
Sequence similaritiesBelongs to the cyclic nucleotide-gated cation channel (TC 1.A.1.5) family. CNGB3 subfamily. Contains 1 cyclic nucleotide-binding domain.