KCNJ4

Several different potassium channels are known to be involved with electrical signaling in the nervous system. One class is activated by depolarization whereas a second class is not. The latter are referred to as inwardly rectifying K+ channels, and they have a greater tendency to allow potassium to flow into the cell rather than out of it. This asymmetry in potassium ion conductance plays a key role in the excitability of muscle cells and neurons. The protein encoded by this gene is an integral membrane protein and member of the inward rectifier potassium channel family. The encoded protein has a small unitary conductance compared to other members of this protein family. Two transcript variants encoding the same protein have been found for this gene.

Full Name

potassium inwardly rectifying channel subfamily J member 4

Function

Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by extracellular barium and cesium (By similarity).

Biological Process

Potassium ion import across plasma membraneManual Assertion Based On ExperimentIBA:GO_Central
Potassium ion transportManual Assertion Based On ExperimentTAS:ProtInc
Regulation of ion transmembrane transportManual Assertion Based On ExperimentIBA:GO_Central

Cellular Location

Cell membrane; Cell junction, synapse, postsynaptic cell membrane; Cytoplasmic vesicle membrane. TAX1BP3 binding promotes dissociation of KCNJ4 from LIN7 famaly members and KCNJ4 internalization.

Topology

Cytoplasmic: 1-55
Helical: 56-80
Extracellular: 81-120
Helical: 121-132
Pore-forming: 133-139
Extracellular: 140-148
Helical: 149-170
Cytoplasmic: 171-445