Multiple sites of interaction between the intracellular domains of an inwardly rectifying potassium channel, Kir6.2.
The amino-terminal and carboxy-terminal domains of inwardly rectifying potassium channel (Kir) subunits are both intracellular. A direct physical interaction between these two domains is involved in the response of Kir channels to regulatory factors such as G-proteins, nucleotides and intracellular pH. We have previously mapped the region within the N-terminal domain of Kir6.2 that interacts with the C-terminus. In this study we use a similar in vitro protein-protein interaction assay to map the regions within the C-terminus which interact with the N-terminus. We find that multiple interaction domains exist within the C-terminus: CID1 (amino acids (aa) 279-323), CID2 (aa 214-222) and CID3 (aa 170-204). These domains correlate with regions previously identified as making important contributions to Kir channel assembly and function. The highly conserved nature of the C-terminus suggests that a similar association with the N-terminus may be a feature common to all members of the Kir family of potassium channels, and that it may be involved in gating of Kir channels by intracellular ligands.
Jones
P A
PA
University Laboratory of Physiology, Parks Road, Oxford OX1 3PT, UK.
Tucker
S J
SJ
Ashcroft
F M
FM
D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment
D024661:Potassium Channels, Inwardly Rectifying; D011993:Recombinant Fusion Proteins