Rat inwardly rectifying potassium channel Kir6.2: cloning electrophysiological characterization, and decreased expression in pancreatic islets of male Zucker diabetic fatty rats.
The ATP-sensitive potassium channel of insulin-secreting pancreatic beta-cells is a complex of Kir6.2, a member of the inwardly rectifying potassium channel superfamily, and the sulfonylurea receptor. We have isolated cDNA clones encoding rat Kir6.2. Co-expression of rat Kir6.2 and sulfonylurea receptor in human embryonic kidney cells generated a potassium current with the properties of the beta-cell ATP-sensitive potassium channel. A quantitative reverse transcriptase-polymerase chain reaction assay indicated that Kir6.2 and sulfonylurea receptor mRNAs were abundantly expressed in rat islets and that expression of Kir6.2 mRNA was reduced by >70% in islets from Zucker diabetic fatty male rats, whereas there was no significant change in sulfonylurea receptor mRNA levels. Thus, decreased expression of Kir6.2 could contribute to the beta-cell dysfunction which characterizes diabetes mellitus in this animal model.
Tokuyama
Y
Y
Department of Medicine, The University of Chicago, Illinois 60637, USA.
Fan
Z
Z
Furuta
H
H
Makielski
J C
JC
Polonsky
K S
KS
Bell
G I
GI
Yano
H
H
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D003920:Diabetes Mellitus / Q000235:genetics / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000503:physiopathology*; D015870:Gene Expression; D005905:Glyburide / Q000494:pharmacology; D006801:Humans; D007515:Islets of Langerhans / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009765:Obesity; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D015221:Potassium Channels / Q000096:biosynthesis / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D011924:Rats, Zucker; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D012016:Reference Values; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D005905:Glyburide