CNGA3 : cyclic nucleotide gated channel subunit alpha 3
Description
The CNGA3 (cyclic nucleotide gated channel subunit alpha 3) is a protein-coding gene located on chromosome 2.
The CNGA3 gene provides instructions for making the alpha subunit of the cone photoreceptor cyclic nucleotide-gated (CNG) channel. These channels are found exclusively in cones, which are located in the retina and are responsible for vision in bright light, including color vision. CNG channels are openings in the cell membrane that transport positively charged atoms (cations) into cells. In cones, CNG channels are open in the dark, allowing cations to flow in. When light enters the eye, it triggers the closure of these channels, stopping the inward flow of cations. This change in cation transport alters the cone's electrical charge, generating a signal interpreted by the brain as vision. This process of translating light into an electrical signal is called phototransduction.
The CNGA3 gene plays a crucial role in visual signal transduction by forming a cation channel in cone photoreceptor cells. This channel is activated by cyclic GMP, leading to depolarization of the cones. This protein exhibits flickering channel gating, reduced outward rectification in the presence of calcium, and increased sensitivity to L-cis diltiazem. When coexpressed with CNGB3, it enhances the cAMP efficacy of the channel. CNGA3 is essential for generating light-evoked electrical responses in red, green, and blue sensitive cones.
CNGA3 is also known as ACHM2, CCNC1, CCNCa, CCNCalpha, CNCG3, CNG3.
