KCNK3 (Potassium Two Pore Domain Channel Subfamily K Member 3) encodes the TASK-1 (TWIK-related acid-sensing potassium channel 1) channel, a pH-sensitive two-pore domain potassium channel expressed throughout the brain and peripheral tissues[1]. TASK-1 is critical for neuronal excitability modulation and has been implicated in various neurological and cardiovascular disorders[2].
| Property | Value |
|---|---|
| Gene Symbol | KCNK3 |
| Full Name | Potassium Two Pore Domain Channel Subfamily K Member 3 |
| Chromosomal Location | 2p23.3 |
| NCBI Gene ID | 3777 |
| OMIM | 603217 |
| Ensembl ID | ENSG00000171303 |
| UniProt ID | O60654 |
KCNK3 encodes the TASK-1 channel, a member of the TWIK-related acid-sensing (TASK) subfamily of two-pore domain potassium channels. TASK-1 channels generate background leak currents that stabilize the resting membrane potential around -70 mV in neurons[1:1]. Key functional properties include:
TASK-1 forms functional homodimers, with each subunit containing four transmembrane segments and two pore domains. The channel's pH sensitivity is mediated by histidine residues in the extracellular pore regions[5].
KCNK3 shows widespread expression:
In the hypothalamus, TASK-1 plays a critical role in chemosensory signaling, detecting pH changes in cerebrospinal fluid and coordinating responses to acidosis[6].
TASK-1 channels are highly expressed in seizure-prone brain regions. The pH sensitivity of TASK-1 makes it particularly relevant to epilepsy, where extracellular pH fluctuations occur during seizure activity[7]. Altered TASK-1 expression has been documented in human temporal lobe epilepsy tissue, suggesting a role in hyperexcitability pathogenesis.
TASK-1 contributes to respiratory chemosensitivity in the carotid body and medulla. The channel's hypoxia sensitivity implicates it in sleep-disordered breathing including obstructive sleep apnea[8].
During ischemic stroke, acidosis develops rapidly in affected brain regions. TASK-1 inhibition by acidosis may contribute to neuronal depolarization and excitotoxic damage following stroke[9].
Given the role in vascular tone regulation and pH sensitivity, TASK-1 may be involved in migraine pathophysiology. Some familial hemiplegic migraine mutations affect similar channels[10].
Similar to TREK-1 (KCNK2), TASK-1 is inhibited by antidepressants. TASK-1 knockout mice show altered stress responses, suggesting a role in mood regulation[11].
TASK-1 is highly expressed in pulmonary artery smooth muscle cells. Dysregulated TASK-1 expression contributes to pulmonary vascular tone maintenance and has been implicated in pulmonary hypertension pathogenesis. TASK-1 blockers are under investigation for this indication[12].
In the heart, TASK-1 contributes to atrial repolarization. Altered expression has been observed in heart failure, suggesting a role in cardiac remodeling[13].
TASK-1 regulates aldosterone secretion from adrenal zona glomerulosa cells by modulating membrane potential and calcium signaling. This links the channel to blood pressure regulation[14].
TASK-1 activity is modulated by:
TASK-1 modulators may provide atrial-selective antiarrhythmic effects without ventricular proarrhythmic risk[13:1].
Selective TASK-1 inhibitors could reduce pulmonary vascular resistance in pulmonary hypertension patients[12:1].
Understanding TASK-1 pH sensitivity may lead to neuroprotective strategies for stroke and traumatic brain injury[9:1].
KCNK3 mutations cause:
Experimental approaches for studying KCNK3:
Bayliss DA, Sirois JE, Talley EM. The TASK family: two-pore domain background K+ channels. Mol Interv. 2003. ↩︎ ↩︎
Patel AJ, Honore E. Molecular physiology of oxygen-sensitive potassium channels. Physiol Rev. 2001. ↩︎
Ma J, Tang X, Li Y, et al. TASK-1 channel: a pH-sensitive potassium channel in neuronal and cardiac cells. Front Cell Neurosci. 2022. ↩︎
Patel AJ, Honore E, Lesage F, et al. Inhalational anesthetics activate two-pore domain background K+ channels. Nat Neurosci. 1999. ↩︎
Riesco-Fagundo CM, Perez-Garcia E, Gonzalez C, et al. pH sensitivity of TASK-1 channels is determined by a single extracellular histidine. J Biol Chem. 2001. ↩︎
Washburn CP, Sirois JE, Talley EM, et al. Serotonergic raphe neurons express TASK channel transcripts and a TASK-like pH- and halothane-sensitive K+ conductance. J Neurosci. 2002. ↩︎
Meuth SG, Kleinschnitz C, Broicher T, et al. The contribution of TWIK-related acid-sensitive K+ 1 to seizure activity in experimental epilepsy. Brain. 2009. ↩︎
Kim D. Physiology and pathophysiology of two-pore domain potassium channels. Biorheology. 2018. ↩︎
Hawro T, Falco A, Schlicht K, et al. The role of TASK channels in cerebral ischemia. Neuroscience. 2020. ↩︎ ↩︎
Brenner M, Kunkel LM. Molecular genetics of migraine. Curr Opin Neurol. 2022. ↩︎
Borsotto M, Veyssiere J, Moha Ou Maati H, et al. Targeting two-pore domain K+ channels: a novel strategy for treating depression?. Pharmacol Ther. 2015. ↩︎
Nagaraj C, Tang B, Balint Z, et al. TASK-1 contributes to hypoxic pulmonary vasoconstriction. Am J Physiol Lung Cell Mol Physiol. 2013. ↩︎ ↩︎
Donner BC, Schullenberg M, Geduldig N, et al. TASK-1 contributes to cardiac action potential repolarization. J Mol Cell Cardiol. 2011. ↩︎ ↩︎
Bandulik S, Penton D, Barbuti N, et al. TASK-1 and TASK-3 channels regulate aldosterone secretion. Cell Physiol Biochem. 2011. ↩︎