Reconstitution of IKATP: An Inward Rectifier Subunit Plus the Sulfonylurea Receptor

@article{Inagaki1995ReconstitutionOI,
  title={Reconstitution of IKATP: An Inward Rectifier Subunit Plus the Sulfonylurea Receptor},
  author={Nobuya Inagaki and Tohru Gonoi and John P. Clement and Noriyuki Namba and Johji Inazawa and Gabriel Emilio Curbelo Gonz{\'a}lez and Lydia Aguilar-Bryan and Susumu Seino and Joseph Bryan},
  journal={Science},
  year={1995},
  volume={270},
  pages={1166 - 1170}
}
A member of the inwardly rectifying potassium channel family was cloned here. The channel, called BIR (Kir6.2), was expressed in large amounts in rat pancreatic islets and glucose-responsive insulin-secreting cell lines. Coexpression with the sulfonylurea receptor SUR reconstituted an inwardly rectifying potassium conductance of 76 picosiemens that was sensitive to adenosine triphosphate (ATP) (IKATP) and was inhibited by sulfonylureas and activated by diazoxide. The data indicate that these… 
Toward understanding the assembly and structure of KATP channels.
TLDR
The cloning and reconstitution of the subunits of these channels demonstrate they are heteromultimers of inwardly rectifying potassium channel subunits (KIR6.x) and sulfonylurea receptors (SUR), members of the ATP-binding cassette (ABC) superfamily.
Octameric Stoichiometry of the KATP Channel Complex
ATP-sensitive potassium (KATP) channels link cellular metabolism to electrical activity in nerve, muscle, and endocrine tissues. They are formed as a functional complex of two unrelated subunits—a
Molecular biology of adenosine triphosphate-sensitive potassium channels.
TLDR
The results indicate that SUR1 is important in sensing nucleotide changes, as implied by its sequence similarity to other ABC proteins, in addition to being the drug sensor, and the inhibitory action of ATP appears to be through a site located on KIR6.2, whose affinity for ATP is modified by SUR1.
The Nucleotide-Binding Sites of SUR1: A Mechanistic Model
KATP channel inhibition by ATP requires distinct functional domains of the cytoplasmic C terminus of the pore-forming subunit.
  • P. Drain, L. Li, J. Wang
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1998
TLDR
This work used systematic chimeric and point mutagenesis and patch-clamp recording to investigate the molecular basis of ATP-dependent inhibition gating of mouse pancreatic beta cell KATP channels expressed in Xenopus oocytes and identified distinct functional domains of the presumed cytoplasmic C-terminal segment of the Kir6.2 subunit that play an important role in this inhibition.
Control of Kir channel gating by cytoplasmic domain interface interactions
TLDR
Results indicate that the stability of the intersubunit CD-I is a major determinant of the inactivation process in Kir6.2 and may control gating in other Kir channels.
Stoichiometry of sulfonylurea-induced ATP-sensitive potassium channel closure.
TLDR
It is concluded that occupation of one of the four SUR sites per channel complex is sufficient to induce KATP channel closure and that the C terminus of SURs does not affect sulfonylurea affinity and sensitivity.
Octameric Stoichiometry of the K ATP Channel Complex
TLDR
The stoichiometry of channel formation is examined using mutant Kir6.2 subunits and dimeric SUR1-Kir6.
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