mShal, a subfamily of A-type K+ channel cloned from mammalian brain.
We have cloned and expressed a mouse brain cDNA, mShal, that encodes a transient, A-type K+ current. mShal, the vertebrate homolog of the Drosophila Shal gene, defines a distinct subfamily of voltage-gated K+ channels. The Shal deduced proteins are more highly conserved between mouse and Drosophila than other presently known K+ channels. mShal carries a "low-threshold" A-type current with a hyperpolarized steady-state inactivation midpoint. Marked similarity was observed between mShal and its Drosophila homolog, fShal, with regard to voltage sensitivity of activation, macroscopic inactivation, steady-state inactivation, and 4-aminopyridine sensitivity. Sequence conservation for Shal proteins is unusually high at the amino terminus, an area considered important for inactivation. Removal of conserved amino-terminal residues from mShal modifies macroscopic inactivation but the transient nature of the current is preserved. Underlying the very high conservation of mShal and fShal may be a role in the nervous system that is conserved in widely divergent species.
Pak
M D
MD
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110.
Baker
K
K
Covarrubias
M
M
Butler
A
A
Ratcliffe
A
A
Salkoff
L
L
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D004330:Drosophila / Q000235:genetics; D004553:Electric Conductivity; D051379:Mice; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000235:genetics* / Q000502:physiology; D012689:Sequence Homology, Nucleic Acid; D051672:Shal Potassium Channels
C497016:Kcnd1 protein, mouse; D015221:Potassium Channels; D051672:Shal Potassium Channels; D004247:DNA