Both transmembrane domains of BK β1 subunits are essential to confer the normal phenotype of β1-containing BK channels.

ABSTRACT: Voltage/Ca²⁺(i)-gated, large conductance K+ (BK) channels result from tetrameric association of α (slo1) subunits. In most tissues, BK protein complexes include regulatory β subunits that contain two transmembrane domains (TM1, TM2), an extracellular loop, and two short intracellular termini. Four BK β types have been identified, each presenting a rather selective tissue-specific expression profile. Thus, BK β modifies current phenotype to suit physiology in a tissue-specific manner. The smooth muscle-abundant BK β1 drastically increases the channel's apparent Ca²⁺(i) sensitivity. The resulting phenotype is critical for BK channel activity to increase in response to Ca2+ levels reached near the channel during depolarization-induced Ca2+ influx and myocyte contraction. The eventual BK chann

SUBMITTER: Kuntamallappanavar G 

PROVIDER: S-EPMC4183656 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature