Cloning of a G protein-activated inwardly rectifying potassium channel from human cerebellum.
Based on sequence homology with the rat atrial G protein-coupled muscarinic potassium channel (GIRK1 or KGA1/KGB1), a human cDNA encoding a G protein-activated inwardly rectifying K+ channel (HGIRK1) was isolated. The cDNA encodes a protein of 501 amino acids and shares 99% identity to rat GIRK1 in its total amino acid sequence. Southern blot analysis of genomic DNA indicates a high degree of conservation among various species. In the human population a useful NlaIII restriction fragment length polymorphism was found in the coding sequence of HGIRK1. Co-expression of HGIRK1 and the 5-HT1A receptor in Xenopus oocytes resulted in opening of the channel upon treatment with serotonin. HGIRK1 currents showed strong inward rectification and could be blocked by extracellular Ba2+. Northern blot analysis shows that HGIRK1 expression in human is most abundant in the brain, while lower levels are round in kidney and heart.
Schoots
O
O
Clarke Institute of Psychiatry, Toronto, Ont., Canada.
Yue
K T
KT
MacDonald
J F
JF
Hampson
D R
DR
Nobrega
J N
JN
Dixon
L M
LM
Van Tol
H H
HH
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002531:Cerebellum / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000187:drug effects*
D015221:Potassium Channels; D019204:GTP-Binding Proteins