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Properties of cloned ATP-sensitive K+ currents expressed in Xenopus oocytes.
Gribble FM
,
Ashfield R
,
Ammälä C
,
Ashcroft FM
.
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1. We have studied the electrophysiological properties of cloned ATP-sensitive K+ channels (KATP channels) heterologously expressed in Xenopus oocytes. This channel comprises a sulphonylurea receptor subunit (SUR) and an inwardly rectifying K+ channel subunit (Kir). 2. Oocytes injected with SUR1 and either Kir6.2 or Kir6.1 exhibited large inwardly rectifying K+ currents when cytosolic ATP levels were lowered by the metabolic inhibitors azide or FCCP. No currents were observed in response to azide in oocytes injected with Kir6.2, Kir6.1 or SUR1 alone, indicating that both the sulphonylurea receptor (SUR1) and an inward rectifier (Kir6.1 or Kir6.2) are needed for functional channel activity. 3. The pharmacological properties of Kir6.2-SUR1 currents resembled those of native beta-cell ATP-sensitive K+ channel currents (KATP currents): the currents were > 90% blocked by tolbutamide (500 microM), meglitinide (10 microM) or glibenclamide (100 nM), and activated 1.8-fold by diazoxide (340 microM), 1.4-fold by pinacidil (1 mM) and unaffected by cromakalim (0.5 mM). 4. Macroscopic Kir6.2-SUR1 currents in inside-out patches were inhibited by ATP with a Ki of 28 microM. Kir6.1-SUR1 currents ran down within seconds of patch excision preventing analysis of ATP sensitivity. 5. No sensitivity to tolbutamide or metabolic inhibition was observed when SUR1 was coexpressed with either Kir1.1a or Kir2.1, suggesting that these proteins do not couple in Xenopus ocytes. 6. Our data demonstrate that the Xenopus oocyte constitutes a good expression system for cloned KATP channels and that expression may be assayed by azide-induced metabolic inhibition.
Aguilar-Bryan,
Cloning of the beta cell high-affinity sulfonylurea receptor: a regulator of insulin secretion.
1995, Pubmed
Aguilar-Bryan,
Cloning of the beta cell high-affinity sulfonylurea receptor: a regulator of insulin secretion.
1995,
Pubmed
Ammälä,
The sulphonylurea receptor confers diazoxide sensitivity on the inwardly rectifying K+ channel Kir6.1 expressed in human embryonic kidney cells.
1996,
Pubmed
Ammälä,
Promiscuous coupling between the sulphonylurea receptor and inwardly rectifying potassium channels.
1996,
Pubmed
,
Xenbase
Ashcroft,
Electrophysiology of the pancreatic beta-cell.
1989,
Pubmed
Ashcroft,
The sulfonylurea receptor.
1992,
Pubmed
Ashcroft,
Rubidium and sodium permeability of the ATP-sensitive K+ channel in single rat pancreatic beta-cells.
1989,
Pubmed
Ashcroft,
Properties and functions of ATP-sensitive K-channels.
1990,
Pubmed
Cook,
Intracellular ATP directly blocks K+ channels in pancreatic B-cells.
,
Pubmed
Dunne,
Intracellular ADP activates K+ channels that are inhibited by ATP in an insulin-secreting cell line.
1986,
Pubmed
Higgins,
ABC transporters: from microorganisms to man.
1992,
Pubmed
Higgins,
The ABC of channel regulation.
1995,
Pubmed
Hilgemann,
Charge movement during Na+ translocation by native and cloned cardiac Na+/Ca2+ exchanger.
1991,
Pubmed
,
Xenbase
Inagaki,
A family of sulfonylurea receptors determines the pharmacological properties of ATP-sensitive K+ channels.
1996,
Pubmed
Inagaki,
Cloning and functional characterization of a novel ATP-sensitive potassium channel ubiquitously expressed in rat tissues, including pancreatic islets, pituitary, skeletal muscle, and heart.
1995,
Pubmed
,
Xenbase
Inagaki,
Reconstitution of IKATP: an inward rectifier subunit plus the sulfonylurea receptor.
1995,
Pubmed
Kakei,
The ATP-sensitivity of K+ channels in rat pancreatic B-cells is modulated by ADP.
1986,
Pubmed
Ko,
The first nucleotide binding fold of the cystic fibrosis transmembrane conductance regulator can function as an active ATPase.
1995,
Pubmed
Miller,
Intracellular compartmentalization of adenosine triphosphate.
1986,
Pubmed
Niki,
The dependence on intracellular ATP concentration of ATP-sensitive K-channels and of Na,K-ATPase in intact HIT-T15 beta-cells.
1989,
Pubmed
Sakura,
Cloning and functional expression of the cDNA encoding a novel ATP-sensitive potassium channel subunit expressed in pancreatic beta-cells, brain, heart and skeletal muscle.
1995,
Pubmed
Takano,
The Ba2+ block of the ATP-sensitive K+ current of mouse pancreatic beta-cells.
1996,
Pubmed
Trube,
Opposite effects of tolbutamide and diazoxide on the ATP-dependent K+ channel in mouse pancreatic beta-cells.
1986,
Pubmed
Tsubaki,
Fourier-transform infrared study of azide binding to the Fea3-CuB binuclear site of bovine heart cytochrome c oxidase: new evidence for a redox-linked conformational change at the binuclear site.
1993,
Pubmed
Tucker,
Inhibitory interactions between two inward rectifier K+ channel subunits mediated by the transmembrane domains.
1996,
Pubmed
,
Xenbase
Vasilyeva,
Kinetic mechanism of mitochondrial adenosine triphosphatase. Inhibition by azide and activation by sulphite.
1982,
Pubmed
Wall,
Isolation of plasma membrane complexes from Xenopus oocytes.
1989,
Pubmed
,
Xenbase
