Kir2.4 channels
| Channel name | Kir2.4 |
| Description | Inwardly rectifying potassium channel Kir2.4 subunit |
| Other names | IRK4 |
| Molecular information | Human (KCNJ14): 434aa, Locus ID: 3770, GenBank: AF181988, AF081466, NM_013348, NM_170720, PMID: 10723734,1 chr. 19q13.1-13.3 |
| Rat (Kcnj14): 434aa, Locus ID 276720, AJ003065, NM_170718, PMID: 9592090,2 chr. 1q22 | |
| Mouse (Kcnj14): 434aa, Locus ID 211480, GenBank: NM_145963, PMID: 10942728,3 12477932,4 chr. 7 | |
| Associated subunits | Can form heteromers with Kir2.1 |
| Functional assays | Voltage-clamp, Western blot |
| Current | Not established |
| Conductance | 15pS (in 140 mM K+) |
| Ion selectivity | K+ |
| Activation | Not established |
| Inactivation | Not established |
| Activators | Extracellular alkalization |
| Gating inhibitors | Extracellular Na+ ions, extracellular acidification (pKa = 7.14 human) |
| Blockers | Nonselective: Ba2+ (IC50 = 72–116 μM at –120 mV3,5), Cs+ (IC50 = 40 μM3) |
| Radioligands | None |
| Channel distribution | Neuronal cells in heart, brain (restricted to cholinergic neurons in striatum and cranial motor nerve nuclei), retina |
| Physiological functions | Setting the membrane potential near EK |
| Mutations and pathophysiology | Not established |
| Pharmacological significance | Not established |
aa, amino acids; chr., chromosome.
↵1. Töpert C, Döring F, Derst C, Daut J, Grzeschik KH, and Karschin A (2000) Cloning structure and assignment to chromosome 19q13 of the human Kir2.4 inwardly rectifying potassium channel gene (KCNJ14). Mamm Genome 11:247-249
↵2. Töpert C, Doring F, Wischmeyer E, Karschin C, Brockhaus J, Ballanyi K, Derst C, and Karschin A (1998) Kir2.4: a novel brain K+ inward rectifier predominantly expressed in motoneurons of cranial nerve nuclei. J Neurosci 18:4096-4105
↵3. Schram G, Melnyk P, Pourrier M, Wang Z, and Nattel S (2002) Kir2.4 and Kir2.1 K+ channel subunits co-assemble: a potential new contributor to inward rectifier current heterogeneity. J Physiol 544:337-349
↵4. Strausberg RL, Feingold EA, Grouse H, Derge JG, Klausner RD, Collins FS, Shenmen CM, Schuler GD, Altshul SF, Zeeberg B, et al. (2002) Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences: Mammalian Gene Collection Program Team. Proc Natl Acad Sci USA 99:16899-16903
↵5. Hughes BA, Kumar G, Yuan Y, Swaminathan A, Yan D, Sharma A, Plumley L, Yang-Feng T, and Swaroop A (2000) Cloning and functional expression of human retinal Kir2.4, a pH-sensitive inwardly rectifying K+ channel. Am J Physiol 279:C771-C784