Functional regulation of BK potassium channels by ?1 auxiliary subunits.

ABSTRACT: Many K(+) channels are oligomeric complexes with intrinsic structural symmetry arising from the homo-tetrameric core of their pore-forming subunits. Allosteric regulation of tetramerically symmetric proteins, whether by intrinsic sensing domains or associated auxiliary subunits, often mirrors the fourfold structural symmetry. Here, through patch-clamp recordings of channel population ensembles and also single channels, we examine regulation of the Ca(2+)- and voltage-activated large conductance Ca(2+)-activated K(+) (BK) channel by associated ?1-subunits. Through expression of differing ratios of ?1:?-subunits, the results reveal an all-or-none functional regulation of BK channels by ?-subunits: channels either exhibit a full gating shift or no shift at all. Furthermore, the ?1-induced shift exhibits a state-dependent labile behavior that recapitulates the fully shifted or unshifted behavior. The ?1-induced shift contrasts markedly to the incremental shifts in BK gating produced by 1-4 ?-subunits and adds a new layer of complexity to the mechanisms by which BK channel functional diversity is generated.

SUBMITTER: Gonzalez-Perez V 

PROVIDER: S-EPMC3977294 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature