Gating of inward rectifier K(+) channels by proton-mediated interactions of intracellular protein domains.
The inward rectifier K(+) channels function in the regulation of myocardial rhythmicity, vascular tones, epithelial transport, and neuronal excitability. Most of these channels are gated by pH. It is now known that the gating process involves a large number of protein domains and amino acid residues in both N- and C-termini of the channel protein. Experimental evidence suggests that at acidic pH, a few titratable residues are protonated in the C-terminus, leading to its interaction with the N-terminus. The N-C-terminal interaction appears to produce vast conformational changes in the channel protein, especially the M2 and M1 sequences, and closes the channels. Thus, gating of these channels requires the N-C-terminal interaction with protons as mediators.
Jiang
Chun
C
Department of Biology, Georgia State University, Atlanta, GA 30302-4010, USA. cjiang@gsu.edu
Qu
Zhiqiang
Z
Xu
Haoxing
H
D020816:Amino Acid Motifs; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating / Q000502:physiology*; D015221:Potassium Channels / Q000737:chemistry / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D011522:Protons
D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011522:Protons