| Structural highlights
Function
KCNK3_MOUSE K(+) channel that conducts voltage-dependent outward rectifying currents upon membrane depolarization. Voltage sensing is coupled to K(+) electrochemical gradient in an 'ion flux gating' mode where outward but not inward ion flow opens the gate (By similarity) (PubMed:12634929, PubMed:18034154, PubMed:18250325, PubMed:28988768, PubMed:9506712). Changes ion selectivity and becomes permeable to Na(+) ions in response to extracellular acidification. Protonation of the pH sensor His-98 stabilizes C-type inactivation conformation likely converting the channel from outward K(+)-conducting, to inward Na(+)-conducting to nonconductive state. Homo- and heterodimerizes to form functional channels with distinct regulatory and gating properties (By similarity). Allows K(+) currents with fast-gating kinetics important for the repolarization and hyperpolarization phases of action potentials (By similarity) (PubMed:18250325). In cerebellar granule cells, heteromeric KCNK3:KCNK9 channel may hyperpolarize the resting membrane potential to limit intrinsic neuronal excitability, but once the action potential threshold is reached, it may support high-frequency action potential firing and increased neuronal excitability (Probable). Dispensable for central chemosensory respiration i.e. breathing controlled by brainstem CO2/pH, it rather conducts pH-sensitive currents and controls the firing rate of serotonergic raphe neurons involved in potentiation of the respiratory chemoreflex. Additionally, imparts chemosensitivity to type 1 cells in carotid bodies which respond to a decrease in arterial oxygen pressure or an increase in carbon dioxide pressure or pH to initiate adaptive changes in pulmonary ventilation (PubMed:18094244, PubMed:18753386). In adrenal gland, contributes to the maintenance of a hyperpolarized resting membrane potential of aldosterone-producing cells at zona glomerulosa and limits aldosterone release as part of a regulatory mechanism that controls arterial blood pressure and electrolyte homeostasis (PubMed:18034154, PubMed:18250325). In brown adipocytes, mediates K(+) efflux that counteracts norepinephrine-induced membrane depolarization, limits Ca(2+) efflux and downstream cAMP and PKA signaling, ultimately attenuating lipid oxidation and adaptive thermogenesis (PubMed:28988768).[UniProtKB:O14649][UniProtKB:O54912][1] [2] [3] [4] [5] [6] [7] [8]
References
- ↑ Morton MJ, O'Connell AD, Sivaprasadarao A, Hunter M. Determinants of pH sensing in the two-pore domain K(+) channels TASK-1 and -2. Pflugers Arch. 2003 Feb;445(5):577-83. PMID:12634929 doi:10.1007/s00424-002-0901-2
- ↑ Heitzmann D, Derand R, Jungbauer S, Bandulik S, Sterner C, Schweda F, El Wakil A, Lalli E, Guy N, Mengual R, Reichold M, Tegtmeier I, Bendahhou S, Gomez-Sanchez CE, Aller MI, Wisden W, Weber A, Lesage F, Warth R, Barhanin J. Invalidation of TASK1 potassium channels disrupts adrenal gland zonation and mineralocorticoid homeostasis. EMBO J. 2008 Jan 9;27(1):179-87. PMID:18034154 doi:10.1038/sj.emboj.7601934
- ↑ Mulkey DK, Talley EM, Stornetta RL, Siegel AR, West GH, Chen X, Sen N, Mistry AM, Guyenet PG, Bayliss DA. TASK channels determine pH sensitivity in select respiratory neurons but do not contribute to central respiratory chemosensitivity. J Neurosci. 2007 Dec 19;27(51):14049-58. PMID:18094244 doi:10.1523/JNEUROSCI.4254-07.2007
- ↑ Davies LA, Hu C, Guagliardo NA, Sen N, Chen X, Talley EM, Carey RM, Bayliss DA, Barrett PQ. TASK channel deletion in mice causes primary hyperaldosteronism. Proc Natl Acad Sci U S A. 2008 Feb 12;105(6):2203-8. PMID:18250325 doi:10.1073/pnas.0712000105
- ↑ Trapp S, Aller MI, Wisden W, Gourine AV. A role for TASK-1 (KCNK3) channels in the chemosensory control of breathing. J Neurosci. 2008 Aug 27;28(35):8844-50. PMID:18753386 doi:10.1523/JNEUROSCI.1810-08.2008
- ↑ Chen Y, Zeng X, Huang X, Serag S, Woolf CJ, Spiegelman BM. Crosstalk between KCNK3-Mediated Ion Current and Adrenergic Signaling Regulates Adipose Thermogenesis and Obesity. Cell. 2017 Nov 2;171(4):836-848.e13. PMID:28988768 doi:10.1016/j.cell.2017.09.015
- ↑ Kim D, Fujita A, Horio Y, Kurachi Y. Cloning and functional expression of a novel cardiac two-pore background K+ channel (cTBAK-1). Circ Res. 1998 Mar 9;82(4):513-8. PMID:9506712 doi:10.1161/01.res.82.4.513
- ↑ Brickley SG, Aller MI, Sandu C, Veale EL, Alder FG, Sambi H, Mathie A, Wisden W. TASK-3 two-pore domain potassium channels enable sustained high-frequency firing in cerebellar granule neurons. J Neurosci. 2007 Aug 29;27(35):9329-40. PMID:17728447 doi:10.1523/JNEUROSCI.1427-07.2007
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