Protein
G protein-activated inward rectifier potassium channel 4
Function
This potassium channel is controlled by G proteins. 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. This receptor plays a crucial role in regulating the heartbeat.Can be blocked by external barium.
Similarity
Belongs to the inward rectifier-type potassium channel (TC 1.A.2.1) family. KCNJ5 subfamily.
Sequence
MAGDSRNAMNQDMEIGVTPRDPKKIPKQARDYIPIATDRTRLLSEGKKPRQRYMEKSGKCNVHHGNVQETYRYLSDLFTTLVDLKWRFNLLVFTMVYTITWLFFGFIWWLIAYIRGDLDHVGDREWIPCVENLSGFVSAFLFSIETETTIGYGFRVITEKCPEGIVLLLVQAILGSIVNAFMVGCMFVKISQPKKRAETLMFSNNAVISLRDEKLCLMFRVGDLRNSHIVEASIRAKLIKSRQTKEGEFIPLNQTDINVGFDTGDDRLFLVSPLIICHEINEKSPFWEMSRAQLTQEEFEVVVILEGMVEATGMTCQARSSYMDTEVLWGHRFTPVLTLEKGFYEVDYNTFHDTYETNTPSCCAKELAEMKREGRLLQYHPSPPLPGGCVGAELGAEAEQEGEEEPEGLSGSQETKDSA