KCNK13
Domain
Each subunit contributes two pore-forming domains 1 and 2 which assemble to form a single pore with M2 and M4 transmembrane helices lining the central cavity and M1 and M3 facing the lipid bilayer. The transmembrane helices are bridged by the selectivity filters 1 and 2 that coordinate the permeant ions. Up to four ions can simultaneously occupy the selectivity filter and at least two elementary charges must translocate across the filter to convert it into the open conformation.
Function
K(+) channel that conducts outward rectifying tonic currents potentiated by purinergic signals (PubMed:24163367, PubMed:25148687, PubMed:30472253, PubMed:38409076). Homo- and heterodimerizes to form functional channels with distinct regulatory and gating properties (PubMed:25148687). Contributes most of K(+) currents at the plasma membrane of resting microglia. Maintains a depolarized membrane potential required for proper ramified microglia morphology and phagocytosis, selectively mediating microglial pruning of presynaptic compartments at hippocampal excitatory synapses (PubMed:38409076). Upon local release of ATP caused by neuronal injury or infection, it is potentiated by P2RY12 and P2RX7 receptor signaling and contributes to ATP-triggered K(+) efflux underlying microglial NLRP3 inflammasome assembly and IL1B release (By similarity) (PubMed:38409076).
Sequence Similarities
Belongs to the two pore domain potassium channel (TC 1.A.1.8) family.
Tissue Specificity
Expressed in microglia (at protein level).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
Alternative names
Potassium channel subfamily K member 13, Tandem pore domain halothane-inhibited potassium channel 1, THIK-1, KCNK13