CNGB1 channels
| Channel name | CNGB11,2 |
| Description | Cyclic nucleotide-gated cation channel B subunit |
| Other names | CNG4, CNGb1, RCNC2 |
| Molecular information | Human CNGB1a: 1245aa, NM_001297, NP_001288, chr: 16q13 |
| Rat CNGB1a: 1339aa, NM_031809, NP_113997, chr. 19p12 | |
| Rat CNGB1b: 858aa, CAA04152, AAC19120 | |
| Mouse CNGB1b: 966aa, XM_286113, XP_286113, chr. 8 C5 | |
| Associated subunits | CNGB1a assembles with CNGA1 in rod photoreceptors; CNGB1b assembles with CNGA2 and CNGA4 in olfactory neurones |
| Functional assays | When assembled with CNGA1 or CNGA2/CNGA4: patch-clamp, calcium imaging |
| Current | Not functional on its own |
| Conductance | Not established |
| Ion selectivity | Not established |
| Activation | Not established |
| Inactivation | Not established |
| Activators | None |
| Gating inhibitors | Ca2+-calmodulin (in native rod and olfactory channel) |
| Blockers | l-cis-diltiazem binds to this subunit and inhibits the current flowing through the CNGA1/CNGB1a channel |
| Radioligands | None |
| Channel distribution | Rod photoreceptors, olfactory neurones, sperm |
| Physiological functions | Ca2+-calmodulin-dependent desensitization of rod and olfactory CNG channel; required for cell surface expression of rod channel |
| Mutations and pathophysiology | Recessive retinitis pigmentosa is caused by the G993V mutation |
| Pharmacological significance | Not established |
| Comments | Splice variants have been identified in various mammals; CNGB1a, the “long” isoform, contains a glutamic acid-rich protein domain (GARP); CNGB1b, the “short” isoform (858aa in rat), does not have this domain; GAR1 (315aa in rat) corresponds to the N terminus of CNGB1a; the GARP domain is involved in association with other proteins |
aa, amino acids; chr., chromosome.
↵1. Ardell MD, Bedsole DL, Schoborg RV, and Pittler SJ (2000) Genomic organization of the human rod photoreceptor cGMP-gated cation channel beta-subunit gene. Gene 245:311-318
↵2. Chen TY, Peng YW, Dhallan RS, Ahamed B, Reed RR, and Yau KW (1993) A new subunit of the cyclic nucleotide-gated cation channel in retinal rods. Nature (Lond) 362:764-767