KCNK1

This gene encodes one of the members of the superfamily of potassium channel proteins containing two pore-forming P domains. The product of this gene has not been shown to be a functional channel, however, it may require other non-pore-forming proteins for activity.

potassium two pore domain channel subfamily K member 1

Ion channel that contributes to passive transmembrane potassium transport and to the regulation of the resting membrane potential in brain astrocytes, but also in kidney and in other tissues (PubMed:15820677, PubMed:21653227).
Forms dimeric channels through which potassium ions pass in accordance with their electrochemical gradient. The channel is selective for K(+) ions at physiological potassium concentrations and at neutral pH, but becomes permeable to Na(+) at subphysiological K(+) levels and upon acidification of the extracellular medium (PubMed:21653227, PubMed:22431633).
The homodimer has very low potassium channel activity, when expressed in heterologous systems, and can function as weakly inward rectifying potassium channel (PubMed:8605869, PubMed:8978667, PubMed:15820677, PubMed:21653227, PubMed:22431633, PubMed:23169818, PubMed:25001086).
Channel activity is modulated by activation of serotonin receptors (By similarity).
Heterodimeric channels containing KCNK1 and KCNK2 have much higher activity, and may represent the predominant form in astrocytes (By similarity).
Heterodimeric channels containing KCNK1 and KCNK3 or KCNK9 have much higher activity (PubMed:23169818).
Heterodimeric channels formed by KCNK1 and KCNK9 may contribute to halothane-sensitive currents (PubMed:23169818).
Mediates outward rectifying potassium currents in dentate gyrus granule cells and contributes to the regulation of their resting membrane potential (By similarity).
Contributes to the regulation of action potential firing in dentate gyrus granule cells and down-regulates their intrinsic excitability (By similarity).
In astrocytes, the heterodimer formed by KCNK1 and KCNK2 is required for rapid glutamate release in response to activation of G-protein coupled receptors, such as F2R and CNR1 (By similarity).
Required for normal ion and water transport in the kidney (By similarity).
Contributes to the regulation of the resting membrane potential of pancreatic beta cells (By similarity).
The low channel activity of homodimeric KCNK1 may be due to sumoylation (PubMed:15820677, PubMed:20498050, PubMed:23169818).
The low channel activity may be due to rapid internalization from the cell membrane and retention in recycling endosomes (PubMed:19959478).

Potassium ion transmembrane transportManual Assertion Based On ExperimentIDA:UniProtKB
Potassium ion transportManual Assertion Based On ExperimentTAS:ProtInc
Regulation of resting membrane potentialManual Assertion Based On ExperimentIMP:UniProtKB
Response to nicotineIEA:Ensembl
Sodium ion transmembrane transportManual Assertion Based On ExperimentIDA:UniProtKB
Stabilization of membrane potentialManual Assertion Based On ExperimentIBA:GO_Central

Cell membrane; Recycling endosome; Cell junction, synapse, synaptic cell membrane; Cytoplasmic vesicle; Perikaryon; Cell projection, dendrite; Cell projection; Apical cell membrane. The heterodimer with KCNK2 is detected at the astrocyte cell membrane. Not detected at the astrocyte cell membrane when KCNK2 is absent. Detected on neuronal cell bodies, and to a lesser degree on neuronal cell projections. Detected on hippocampus dentate gyrus granule cell bodies and to a lesser degree on proximal dendrites. Detected at the apical cell membrane in stria vascularis in the cochlea. Detected at the apical cell membrane of vestibular dark cells situated between the crista and the utricle in the inner ear. Detected at the apical cell membrane in kidney proximal tubule segment S1 and in subapical compartments in segments S1, S2 and S3. Predominantly in cytoplasmic structures in kidney distal convoluted tubules and collecting ducts (By similarity).
Detected at the apical cell membrane of bronchial epithelial cells (PubMed:21964404).

Cytoplasmic: 1-20
Helical: 21-41
Extracellular: 42-103
Helical: 104-122
Extracellular: 123-132
Helical: 133-156
Cytoplasmic: 157-181
Helical: 182-202
Extracellular: 203-211
Helical: 212-231
Extracellular: 232-243
Helical: 244-267
Cytoplasmic: 268-336

Sumoylation is controversial. Sumoylated by UBE2I (PubMed:15820677).
Not sumoylated when expressed in xenopus oocytes or mammalian cells (PubMed:17693262).
Sumoylation inactivates the channel, but does not interfere with expression at the cell membrane (PubMed:15820677).
Sumoylation of a single subunit is sufficient to silence the dimeric channel (PubMed:20498050, PubMed:23169818).
Sumoylation of KCNK1 is sufficient to silence heterodimeric channels formed by KCNK1 and KCNK3 or KCNK9 (PubMed:23169818).
Desumoylated by SENP1; this activates the channel (PubMed:15820677, PubMed:20498050, PubMed:23169818).
Desumoylated by SENP1; this strongly increases halothane-mediated activation of heterodimeric channels formed with KCNK9 (PubMed:23169818).
SENP1 treatment has no effect (PubMed:17693262).