Structural highlights
Function
[IRK3_MOUSE] 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.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Inward rectifier K(+) channels govern the resting membrane voltage in many cells. Regulation of these ion channels via G protein-coupled receptor signaling underlies the control of heart rate and the actions of neurotransmitters in the central nervous system. We have determined the protein structure formed by the intracellular N- and C termini of the G protein-gated inward rectifier K(+) channel GIRK1 at 1.8 A resolution. A cytoplasmic pore, conserved among inward rectifier K(+) channels, extends the ion pathway to 60 A, nearly twice the length of a canonical transmembrane K(+) channel. The cytoplasmic pore is lined by acidic and hydrophobic amino acids, creating a favorable environment for polyamines, which block the pore. These results explain in structural and chemical terms the basis of inward rectification, and they also have implications for G protein regulation of GIRK channels.
Structural basis of inward rectification: cytoplasmic pore of the G protein-gated inward rectifier GIRK1 at 1.8 A resolution.,Nishida M, MacKinnon R Cell. 2002 Dec 27;111(7):957-65. PMID:12507423[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Nishida M, MacKinnon R. Structural basis of inward rectification: cytoplasmic pore of the G protein-gated inward rectifier GIRK1 at 1.8 A resolution. Cell. 2002 Dec 27;111(7):957-65. PMID:12507423
