A region of the sulfonylurea receptor critical for a modulation of ATP-sensitive K(+) channels by G-protein betagamma-subunits.
To determine the interaction site(s) of ATP-sensitive K(+) (K(ATP)) channels for G-proteins, sulfonylurea receptor (SUR2A or SUR1) and pore-forming (Kir6.2) subunits were reconstituted in the mammalian cell line, COS-7. Intracellular application of the G-protein betagamma2-subunits (G(betagamma)(2)) caused a reduction of ATP-induced inhibition of Kir6.2/SUR channel activities by lessening the ATP sensitivity of the channels. G(betagamma)(2) bound in vitro to both intracellular (loop-NBD) and C-terminal segments of SUR2A, each containing a nucleotide-binding domain (NBD). Furthermore, a single amino acid substitution in the loop-NBD of SUR (Arg656Ala in SUR2A or Arg665Ala in SUR1) abolished the G(betagamma)(2)-dependent alteration of the channel activities. These findings provide evidence that G(betagamma) modulates K(ATP) channels through a direct interaction with the loop-NBD of SUR.
Wada
Y
Y
Department of Neurochemistry, Tokyo Institute of Psychiatry, 2-1-8 Kamikitazawa, Setagaya-ku, Tokyo 156-8585, Japan.
Yamashita
T
T
Imai
K
K
Miura
R
R
Takao
K
K
Nishi
M
M
Takeshima
H
H
Asano
T
T
Morishita
R
R
Nishizawa
K
K
Kokubun
S
S
Nukada
T
T
D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002417:Cattle; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D011955:Receptors, Drug / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D064233:Sulfonylurea Receptors
D018528:ATP-Binding Cassette Transporters; C577509:Abcc8 protein, rat; D000596:Amino Acids; D018076:DNA, Complementary; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011955:Receptors, Drug; D011993:Recombinant Fusion Proteins; D064233:Sulfonylurea Receptors; D000255:Adenosine Triphosphate; D006899:Mixed Function Oxygenases; D005982:Glutathione Transferase; D019204:GTP-Binding Proteins