K2P4.1 channels
| Channel name | K2P4.1 |
| Description | Two-pore domain potassium channel subunit; open rectifier |
| Other names | KCNK4, TRAAK |
| Molecular information | Human: 393aa, NM_016611, chr. 11q13, KCNK4,1 GeneID: 50801, PMID: 107674091 |
| Rat: 397aa, NM_053804, kcnk4 | |
| Mouse: 398aa, NM_008431, chr. 19, kcnk4 | |
| Associated subunits | Not established |
| Functional assays | Electrophysiological2 |
| Current | Open rectifier |
| Conductance | 46pS |
| Ion selectivity | Not established |
| Activation | See “Comments” |
| Inactivation | See “Comments” |
| Activators | Arachidonic acid (10 mM),3 mechanical stress,4 heat6 (see “Comments”), unsaturated fatty acids,3 lysopholipids,7 riluzole8 |
| Gating inhibitors | None |
| Blockers | Gd+ |
| Radioligands | None |
| Channel distribution | Brain,5 kidney, small intestine, placenta, prostate |
| Physiological functions | Not established |
| Mutations and pathophysiology | Not established |
| Pharmacological significance | Not established |
| Comments | Activation and deactivation with voltage steps seem to be instantaneous; knockout mice have no obvious phenotype9; the open probability of K2P4 increases with temperature with an activation threshold of 31°C in COS-7 cells |
aa, amino acids; chr., chromosome.
↵1. Lesage F, Maingret F, and Lazdunski M (2000) Cloning and expression of human TRAAK, a poly-unsaturated fatty acids-activated and mechano-sensitive K(+) channel. FEBS Lett 471:137-140
↵2. Kim Y, Bang H, Gnatenco C, and Kim D (2001) Synergistic interaction and the role of C-terminus in the activation of TRAAK K+ channels by pressure, free fatty acids and alkali. Pflueg Arch Eur J Physiol 442:64-72
↵3. Fink M, Lesage F, Duprat F, Heurteaux C, Reyes R, Fosset M, and Lazdunski M (1998) A neuronal two P domain K+ channel stimulated by arachidonic acid and polyunsaturated fatty acids. EMBO J 17:3297-3308
↵4. Maingret F, Fosset M, Lesage F, Lazdunski M, and Honoré E (1999) TRAAK is a mammalian neuronal mechanogated K+ channel. J Biol Chem 274:1381-1387
↵5. Reyes R, Lauritzen I, Lesage F, Ettaiche M, Fosset M, and Lazdunski M (2000) Immunolocalization of the arachidonic acid and mechanosensitive baseline traak potassium channel in the nervous system. Neuroscience 95:893-901
↵6. Kang DW, Choe CY, and Kim D (2005) Thermosensitivity of the two-pore domain K+ channels TREK-2 and TRAAK. J Physiol 564.1:103-116
↵7. Maingret F, Patel AJ, Lesage F, Lazdunski M, and Honoré E (2000) Lysophospholipids open the two-pore domain mechano-gated K(+) channels TREK-1 and TRAAK. J Biol Chem 275:10128-10133
↵8. Duprat F, Lesage F, Patel AJ, Fink M, Romey G, and Lazdunski M (2000) The neuroprotective agent riluzole activates the two P domain K + channels TREK-1 and TRAAK. Mol Pharmacol 57:906-912
↵9. Heurteaux C, Guy N, Laigle C, Blondeau N, Duprat F, Mazzuca M, Lang-Lazdunski L, Widmann C, Zanzouri M, Romey G, et al. (2004) TREK-1, a K+ channel involved in neuroprotection and general anesthesia. EMBO J 23:2684-2695