Hypochlorous acid modifies calcium release channel function from skeletal muscle sarcoplasmic reticulum.
Hypochlorous acid modifies calcium release channel function from skeletal muscle sarcoplasmic reticulum.
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DOI：
10.1152/japplphysiol.00645.2002
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发表时间：
2003-04
影响因子：
3.3
通讯作者：
T. G. Favero;J. Webb;M. Papiez;E. Fisher;Robert J. Trippichio;M. Broide;J. Abramson
中科院分区：
文献类型：
--
作者：
T. G. Favero;J. Webb;M. Papiez;E. Fisher;Robert J. Trippichio;M. Broide;J. Abramson
我们以前已经证明，在毫摩尔浓度的过氧化氢诱导钙（2+）释放从积极加载肌浆网（SR）囊泡，并诱导双相[（3）H]ryanodine结合行为。考虑到次氯酸（HOCl）是一种相关的自由基，并已被证明是一种更有效的蛋白质氧化剂，我们评估了HOCl对肌浆网Ca（2+）通道释放机制的影响。HOCl以浓度依赖性方式激活SR Ca（2+）释放通道，并诱导Ca从活性负载囊泡中快速释放。HOCl诱导的Ca（2+）释放在存在毫摩尔浓度的DMSO时被抑制。高亲和力[（3）H]ryanodine结合也在10至100 μ M的浓度下增强。在HOCl浓度>100 μ M时，平衡结合被抑制。HOCl刺激结合被二硫苏糖醇抑制。在单通道重构实验中进一步证实了HOCl与Ca（2+）释放机制之间的直接相互作用。20 μ M的HOCl在SR囊泡与双层脂质膜融合后激活Ca（2+）释放通道。在40 μ M时，Ca（2+）通道活性受到抑制。SR囊泡与HOCl的预处理抑制荧光探针的荧光发展的巯基通道功能的关键。这些结果表明，HOCl在微摩尔浓度可以修改SR Ca（2+）的处理。
We have previously demonstrated that H2O2 at millimolar concentrations induces Ca(2+) release from actively loaded sarcoplasmic reticulum (SR) vesicles and induces biphasic [(3)H]ryanodine binding behavior. Considering that hypochlorous acid (HOCl) is a related free radical and has been demonstrated to be a more effective oxidant of proteins, we evaluated the effects of HOCl on sarcoplasmic reticulum Ca(2+)-channel release mechanism. In a concentration-dependent manner, HOCl activates the SR Ca(2+) release channel and induces rapid release of Ca from actively loaded vesicles. HOCl-induced Ca(2+) release is inhibited in the presence of millimolar concentrations of DMSO. High-affinity [(3)H]ryanodine binding is also enhanced at concentrations from 10 to 100 microM. At HOCl concentrations of >100 microM, equilibrium binding is inhibited. HOCl stimulation of binding is inhibited by the addition of dithiothreitol. The direct interaction between HOCl and the Ca(2+) release mechanism was further demonstrated in single-channel reconstitution experiments. HOCl, at 20 microM, activated the Ca(2+) release channel after fusion of a SR vesicle to a bilayer lipid membrane. At 40 microM, Ca(2+)-channel activity was inhibited. Pretreatment of SR vesicles with HOCl inhibited the fluorescence development of a fluorogenic probe specific to thiol groups critical to channel function. These results suggest that HOCl at micromolar concentrations can modify SR Ca(2+) handling.