Elimination of the BKCa Channel's High-Affinity Ca2+ Sensitivity
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چکیده
منابع مشابه
Elimination of the BKCa Channel's High-Affinity Ca2+ Sensitivity
We report here a combination of site-directed mutations that eliminate the high-affinity Ca(2+) response of the large-conductance Ca(2+)-activated K(+) channel (BK(Ca)), leaving only a low-affinity response blocked by high concentrations of Mg(2+). Mutations at two sites are required, the "Ca(2+) bowl," which has been implicated previously in Ca(2+) binding, and M513, at the end of the channel'...
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It has been established that the large conductance Ca(2+)-activated K(+) channel contains two types of high-affinity Ca(2+) binding sites, termed the Ca(2+) bowl and the RCK1 site. The affinities of these sites, and how they change as the channel opens, is still a subject of some debate. Previous estimates of these affinities have relied on fitting a series of conductance-voltage relations dete...
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There is controversy over whether Ca(2+) binds to the BK(Ca) channel's intracellular domain or its integral-membrane domain and over whether or not mutations that reduce the channel's Ca(2+) sensitivity act at the point of Ca(2+) coordination. One region in the intracellular domain that has been implicated in Ca(2+) sensing is the "Ca(2+) bowl". This region contains many acidic residues, and la...
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The large-conductance Ca(2+)-activated potassium (BK(Ca)) channel of smooth muscle is unusually sensitive to Ca(2+) as compared with the BK(Ca) channels of brain and skeletal muscle. This is due to the tissue-specific expression of the BK(Ca) auxiliary subunit beta1, whose presence dramatically increases both the potency and efficacy of Ca(2+) in promoting channel opening. beta1 contains no Ca(...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 2002
ISSN: 1540-7748,0022-1295
DOI: 10.1085/jgp.20028627