Characterization of a mammalian cDNA for an inactivating voltage-sensitive K+ channel.
A cDNA clone encoding a K+ channel polypeptide with 72% amino acid sequence identity to Drosophila Shal was isolated from rat hippocampus. Functional expression of the cDNA in Xenopus oocytes generated 4-amino-pyridine-sensitive K+ channels displaying rapid inactivation kinetics. The fastest component of inactivation was slowed by the deletion of 3 basic residues in the amino-terminal region. Northern blots revealed that the mRNA encoding this K+ channel polypeptide was expressed at a similar level in the brain and in the heart. In situ hybridization revealed that the mRNA encoding this K+ channel appeared concentrated in the hippocampus, dentate gyrus, and habenular nucleus in the brain. Thus, this K+ channel polypeptide is likely to form some of the A-type K+ channels expressed in the mammalian nervous system and heart.
Baldwin
T J
TJ
Howard Hughes Medical Institute, University of California, San Francisco 94143-0724.
Tsaur
M L
ML
Lopez
G A
GA
Jan
Y N
YN
Jan
L Y
LY
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D015870:Gene Expression; D006321:Heart / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D015640:Ion Channel Gating; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D015221:Potassium Channels / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D016415:Sequence Alignment
D009838:Oligodeoxyribonucleotides; D015221:Potassium Channels; D012333:RNA, Messenger