| Inward rectifier potassium channel | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 crystal structure of an inward rectifier potassium channel | |||||||||
| Identifiers | |||||||||
| Symbol | IRK | ||||||||
| Pfam | PF01007 | ||||||||
| Pfam clan | CL0030 | ||||||||
| InterPro | IPR013521 | ||||||||
| SCOP2 | 1n9p / SCOPe / SUPFAM | ||||||||
| TCDB | 1.A.2 | ||||||||
| OPM superfamily | 8 | ||||||||
| OPM protein | 3SPG | ||||||||
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Inward-rectifier potassium channels (Kir, IRK) are a specific lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types,[1] plants,[2] and bacteria.[3] They are activated by phosphatidylinositol 4,5-bisphosphate (PIP2). The malfunction of the channels has been implicated in several diseases.[4][5] IRK channels possess a pore domain, homologous to that of voltage-gated ion channels, and flanking transmembrane segments (TMSs). They may exist in the membrane as homo- or heterooligomers and each monomer possesses between 2 and 4 TMSs. In terms of function, these proteins transport potassium (K+), with a greater tendency for K+ uptake than K+ export.[3] The process of inward-rectification was discovered by Denis Noble in cardiac muscle cells in 1960s[6] and by Richard Adrian and Alan Hodgkin in 1970 in skeletal muscle cells.[7]
- ^ Kubo Y, Adelman JP, Clapham DE, Jan LY, Karschin A, Kurachi Y, et al. (December 2005). "International Union of Pharmacology. LIV. Nomenclature and Molecular Relationships of Inwardly Rectifying Potassium Channels". Pharmacological Reviews. 57 (4): 509–26. doi:10.1124/pr.57.4.11. PMID 16382105. S2CID 11588492.
- ^ Hedrich R, Moran O, Conti F, Busch H, Becker D, Gambale F, et al. (1995). "Inward rectifier potassium channels in plants differ from their animal counterparts in response to voltage and channel modulators". European Biophysics Journal. 24 (2): 107–15. doi:10.1007/BF00211406. PMID 8582318. S2CID 12718513.
- ^ a b "1.A.2 Inward Rectifier K Channel (IRK-C) Family". TCDB. Retrieved 2016-04-09.
- ^ Hansen SB (May 2015). "Lipid agonism: The PIP2 paradigm of ligand-gated ion channels". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 1851 (5): 620–8. doi:10.1016/j.bbalip.2015.01.011. PMC 4540326. PMID 25633344.
- ^ Abraham MR, Jahangir A, Alekseev AE, Terzic A (November 1999). "Channelopathies of inwardly rectifying potassium channels". FASEB Journal. 13 (14): 1901–10. doi:10.1096/fasebj.13.14.1901. PMID 10544173. S2CID 22205168.
- ^ Noble, Denis (December 1965). "Electrical properties of cardiac muscle attributable to inward going (anomalous) rectification". Journal of Cellular and Comparative Physiology. 66 (S2): 127–135. doi:10.1002/jcp.1030660520. ISSN 0095-9898.
- ^ Adrian RH, Chandler WK, Hodgkin AL (July 1970). "Slow changes in potassium permeability in skeletal muscle". The Journal of Physiology. 208 (3): 645–68. doi:10.1113/jphysiol.1970.sp009140. PMC 1348790. PMID 5499788.