A calcium switch for the functional coupling between a (hslo) and beta subunits (K-v,K-Ca beta) of maxi K channels

被引:170
作者
Meera, P [1 ]
Wallner, M [1 ]
Jiang, Z [1 ]
Toro, L [1 ]
机构
[1] UNIV CALIF LOS ANGELES, DEPT ANESTHESIOL, LOS ANGELES, CA 90095 USA
来源
FEBS LETTERS | 1996年 / 382卷 / 1-2期
关键词
MaxiK channel; calcium-independent activation; calcium-dependent activation; human myometrium; subunit interaction alpha-beta;
D O I
10.1016/0014-5793(96)00151-2
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
K-V?(Ca)beta subunit dramatically increases the apparent calcium sensitivity of the alpha subunit of MaxiK channels when probed in the micromolar [Ca2+](i) range, Analysis in a wide range of [Ca2+](i) revealed that this functional coupling is exquisitely modulated by [Ca2+](i). Ca2+ ions switch MaxiK alpha+beta complex into a functionally coupled state at concentrations beyond resting [Ca2+](i). At [Ca2+] less than or equal to 100 nM, MaxiK activity becomes independent of Ca2+, is purely voltage-activated, and its functional coupling with its beta subunit is released. The functional switch develops at [Ca2+](i) that occur during cellular excitation, providing the molecular basis of how MaxiK channels regulate smooth muscle excitability and neurotransmitter release.
引用
收藏
页码:84 / 88
页数:5
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