Cloning, expression, and distribution of functionally distinct Ca(2+)-activated K+ channel isoforms from human brain.
We have cloned and expressed nine Ca(2+)-activated K+ channel isoforms from human brain. The open reading frames encode proteins ranging from 1154 to 1195 amino acids, and all possess significant identity with the slowpoke gene products in Drosophila and mouse. All isoforms are generated by alternative RNA splicing of a single gene on chromosome 10 at band q22.3 (hslo). RNA splicing occurs at four sites located in the carboxy-terminal portion of the protein and gives rise to at least nine ion channel constructs (hbr1-hbr9). hslo mRNA is expressed abundantly in human brain, and individual isoforms show unique expression patterns. Expression of hslo mRNA in Xenopus oocytes produces robust voltage and Ca(2+)-activated K+ currents. Splice variants differ significantly in their Ca2+ sensitivity, suggesting a broad functional role for these channels in the regulation of neuronal excitability.
Tseng-Crank
J
J
Glaxo Research Institute, Research Triangle Park, North Carolina 27709.
Foster
C D
CD
Krause
J D
JD
Mertz
R
R
Godinot
N
N
DiChiara
T J
TJ
Reinhart
P H
PH
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002879:Chromosomes, Human, Pair 10; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D015870:Gene Expression; D005796:Genes; D006801:Humans; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D008969:Molecular Sequence Data; D009865:Oocytes; D015221:Potassium Channels / Q000145:classification / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014982:Xenopus laevis
D017931:DNA Primers; C494841:KCNMA1 protein, human; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D015221:Potassium Channels; D012333:RNA, Messenger; D002118:Calcium