Actions of sulfhydryl reagents on single ryanodine receptor Ca2+-release channels from sheep myocardium
Actions of sulfhydryl reagents on single ryanodine receptor Ca2+-release channels from sheep myocardium
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DOI：
10.1152/ajpcell.1997.272.6.c1908
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发表时间：
1997-06-01
影响因子：
5.5
通讯作者：
Dulhunty, AF
中科院分区：
文献类型：
--
作者：
Eager, KR;Roden, LD;Dulhunty, AF
报道了反应性二硫化物2，2 '-和4，4'-二硫代二吡啶对掺入脂质双分子层的单一心脏兰尼碱受体（RyR）离子通道的作用。RyR在加入反应性二硫化物（10（-7）至10（-3）M）的几分钟内被激活，在大于或等于10（-4）M的浓度下激活后通道活性不可逆地丧失。在10（-9）和2 x 10（-2）M之间的细胞质（顺式）Ca 2+浓度的宽范围内观察到这种激活，随后失去活性。并且在较高的反应性二硫化物浓度下或当RyR最初在10（-5）或10（-3）M Ca 2+下具有活性时发生得更快。反应性二硫化物通过将长组分引入开放时间分布来增加通道开放概率，使平均通道开放时间增加高达50倍。巯基试剂不会改变闭合时间分布。还原剂二硫苏糖醇和谷胱甘肽（1-10 mM）可防止反应性二硫化物的作用。结果表明，RyR复合物上的半胱氨酸残基可以调节离子通道门控机制。
Effects of the reactive disulfides, 2,2'- and 4,4'-dithiodipyridine, on single cardiac ryanodine receptor (RyR) ion channels incorporated into lipid bilayers are reported. RyRs are activated within minutes of addition of the reactive disulfides (10(-7) to 10(-3) M) with an irreversible loss of channel activity after the activation at concentrations greater than or equal to 10(-4) M. This activation, followed by loss of activity, is seen over a wide range of cytoplasmic (cis) Ca2+ concentration between 10(-9) and 2 x 10(-2) M. and occurs more rapidly with higher reactive disulfide concentrations or when RyRs are initially active at 10(-5) or 10(-3) M Ca2+. The reactive disulfides increase the channel open probability by introducing long components into the open time distributions, increasing the mean channel open time by up to 50-fold. Closed time distributions are not altered by the sulfhydryl reagents. The effects of the reactive disulfides are prevented by the reducing agents dithiothreitol and glutathione (1-10 mM). The results suggest that cysteine residues on the RyR complex can regulate the ion channel gating mechanisms.