Association and stoichiometry of K(ATP) channel subunits

Neuron. 1997 May;18(5):827-38. doi: 10.1016/s0896-6273(00)80321-9.


ATP-sensitive potassium channels (K(ATP) channels) are heteromultimers of sulfonylurea receptors (SUR) and inwardly rectifying potassium channel subunits (K(IR)6.x) with a (SUR-K(IR)6.x)4 stoichiometry. Association is specific for K(IR)6.x and affects receptor glycosylation and cophotolabeling of K(IR)6.x by 125I-azidoglibenclamide. Association produces digitonin stable complexes with an estimated mass of 950 kDa. These complexes can be purified by lectin chromatography or by using Ni2(+)-agarose and a his-tagged SUR1. Expression of SUR1 approximately (K(IR)6.2)i fusion constructs shows that a 1:1 SUR1:K(IR)6.2 stoichiometry is both necessary and sufficient for assembly of active K(ATP) channels. Coexpression of a mixture of strongly and weakly rectifying triple fusion proteins, rescued by SUR1, produced the three channel types expected of a tetrameric pore.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / pharmacology
  • Adenosine Triphosphate / physiology*
  • Affinity Labels
  • Animals
  • COS Cells / physiology
  • Diazoxide / pharmacology
  • Glyburide / analogs & derivatives
  • Glycosylation
  • Histidine / chemistry
  • Ion Channel Gating / physiology
  • Molecular Weight
  • Mutagenesis / physiology
  • Patch-Clamp Techniques
  • Photochemistry
  • Potassium Channels / chemistry*
  • Potassium Channels / drug effects
  • Potassium Channels / genetics
  • Recombinant Fusion Proteins / physiology
  • Sulfonylurea Compounds / pharmacology


  • Affinity Labels
  • Potassium Channels
  • Recombinant Fusion Proteins
  • Sulfonylurea Compounds
  • iodoglibenclamide
  • Histidine
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Diazoxide
  • Glyburide