Channel name | CNGA31,2,3,4,5 |
Description | Cyclic nucleotide-gated cation channel A subunit |
Other names | CNG3, CNGa2, CCNC1 |
Molecular information | Human: 694aa, NM_001298, NP_001298, chr. 2q11.2 |
Rat: 611aa, NM_053495, NP_445947, chr. 9q21 | |
Mouse: 631aa, NM_009918, NP_034048, chr. 1 B | |
Associated subunits | CNGB3 (cone photoreceptor channel: 2 CNGA3:2 CNGB3) |
Functional assays | Patch-clamp, calcium imaging |
Current | Cyclic nucleotide-activated current |
Conductance | 40pS |
Ion selectivity | Ca2+ > K+ ∼ Na+ |
Activation | Not established |
Inactivation | Not established |
Activators | cGMP » cAMP (partial agonist) |
Gating modifiers | None |
Blockers | l-cis-diltiazem (in the presence of CNGB3) |
Radioligands | None |
Channel distribution | Cone photoreceptor, subpopulation of olfactory neurones, some central neurones, pinealocytes, sperm |
Physiological functions | Light transduction (daylight, color vision) |
Mutations and pathophysiology | Missense mutations in CNGA3 cause achromatopsia (rod monochromacy) and retinal degeneration |
Pharmacological significance | Not established |
aa, amino acids; chr., chromosome.
↵1. Biel M, Zong X, Distler M, Bosse E, Klugbauer N, Murakami M, Flockerzi V, and Hofmann F (1994) Another member of the cyclic nucleotide-gated channel family, expressed in testis, kidney, and heart. Proc Natl Acad Sci USA 91:3505-3509
↵2. Bonigk W, Altenhofen W, Muller F, Dose A, Illing M, Molday RS, and Kaupp UB (1993) Rod and cone photoreceptor cells express distinct genes for cGMP-gated channels. Neuron 10:865-877
↵3. Hirano AA, Hack I, Wassle H, and Duvoisin RM (2000) Cloning and immuno cytochemical localization of a cyclic nucleotide-gated channel alpha-subunit to all cone photoreceptors in the mouse retina. J Comp Neurol 421:80-94
↵4. Weyand I, Godde M, Frings S, Weiner J, Muller F, Altenhofen W, Hatt H, and Kaupp UB (1994) Cloning and functional expression of a cyclic-nucleotide-gated channel from mammalian sperm. Nature (Lond) 368:859-863
↵5. Yu WP, Grunwald ME, and Yau KW (1996) Molecular cloning, functional expression and chromosomal localization of a human homolog of the cyclic nucleotide-gated ion channel of retinal cone photoreceptors. FEBS Lett 393:211-215