The beta subunit increases the Ca2+ sensitivity of large conductance Ca2+-activated potassium channels by retaining the gating in the bursting states.

ABSTRACT: Coexpression of the beta subunit (KV,Cabeta) with the alpha subunit of mammalian large conductance Ca2+- activated K+ (BK) channels greatly increases the apparent Ca2+ sensitivity of the channel. Using single-channel analysis to investigate the mechanism for this increase, we found that the beta subunit increased open probability (Po) by increasing burst duration 20-100-fold, while having little effect on the durations of the gaps (closed intervals) between bursts or on the numbers of detected open and closed states entered during gating. The effect of the beta subunit was not equivalent to raising intracellular Ca2+ in the absence of the beta subunit, suggesting that the beta subunit does not act by increasing all the Ca2+ binding rates proportionally. The beta subunit also inhibited tran

SUBMITTER: Nimigean CM 

PROVIDER: S-EPMC2222905 | biostudies-literature | 1999 Mar

REPOSITORIES: biostudies-literature