Molecular basis of fast inactivation in voltage and Ca2+-activated K+ channels: a transmembrane beta-subunit homolog.

ABSTRACT: Voltage-dependent and calcium-sensitive K+ (MaxiK) channels are key regulators of neuronal excitability, secretion, and vascular tone because of their ability to sense transmembrane voltage and intracellular Ca2+. In most tissues, their stimulation results in a noninactivating hyperpolarizing K+ current that reduces excitability. In addition to noninactivating MaxiK currents, an inactivating MaxiK channel phenotype is found in cells like chromaffin cells and hippocampal neurons. The molecular determinants underlying inactivating MaxiK channels remain unknown. Herein, we report a transmembrane beta subunit (beta2) that yields inactivating MaxiK currents on coexpression with the pore-forming alpha subunit of MaxiK channels. Intracellular application of trypsin as well as deletion of 19 N-ter

SUBMITTER: Wallner M 

PROVIDER: S-EPMC22433 | biostudies-literature | 1999 Mar

REPOSITORIES: biostudies-literature