期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2014
卷号：111
期号：13
页码：4868-4873
DOI：10.1073/pnas.1322123111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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 Ca2+- and voltage-activated large conductance Ca2+-activated K+ (BK) channel by associated {gamma}1-subunits. Through expression of differing ratios of {gamma}1:-subunits, the results reveal an all-or-none functional regulation of BK channels by {gamma}-subunits: channels either exhibit a full gating shift or no shift at all. Furthermore, the {gamma}1-induced shift exhibits a state-dependent labile behavior that recapitulates the fully shifted or unshifted behavior. The {gamma}1-induced shift contrasts markedly to the incremental shifts in BK gating produced by 1-4 {beta}-subunits and adds a new layer of complexity to the mechanisms by which BK channel functional diversity is generated.
