Xiong H, Buck E, Stuart J, Pessah I N, Salama G, Abramson J J
Department of Physics, Portland State University, Oregon 97207.
Arch Biochem Biophys. 1992 Feb 1;292(2):522-8. doi: 10.1016/0003-9861(92)90025-r.
The photooxidizing xanthene dye rose bengal (10 nM to 1 microM) stimulates rapid Ca2+ release from skeletal muscle sarcoplasmic reticulum vesicles. Following fusion of sarcoplasmic reticulum (SR) vesicles to an artificial bilayer, reconstituted Ca2+ channel activity is stimulated by nanomolar concentrations of rose bengal in the presence of a broad-spectrum light source. Rose bengal does not appear to affect K+ channels present in the SR. Following reconstitution of the sulfhydryl-activated 106-kDa Ca2+ channel protein into a bilayer, rose bengal activates the isolated protein in a light-dependent manner. Ryanodine at a concentration of 10 nM is shown to lock the 106-kDa channel protein in a subconductance state which can be reversed by subsequent addition of 500 nM rose bengal. This apparent displacement of bound ryanodine by nanomolar concentrations of rose bengal is also directly observed upon measurement of [3H]ryanodine binding to JSR vesicles. These observations indicate that photooxidation of rose bengal causes a stimulation of the Ca2+ release protein from skeletal muscle sarcoplasmic reticulum by interacting with the ryanodine binding site. Furthermore, similar effects of rose bengal on isolated SR vesicles, on single channel measurements following fusion of SR vesicles, and following incorporation of the isolated 106-kDa protein strongly implicates the 106-kDa sulfhydryl-activated Ca2+ channel protein in the Ca2+ release process.
光氧化呫吨染料孟加拉玫瑰红（10 nM至1 μM）可刺激骨骼肌肌浆网囊泡快速释放Ca2+。肌浆网（SR）囊泡与人工双层膜融合后，在广谱光源存在的情况下，纳摩尔浓度的孟加拉玫瑰红可刺激重组Ca2+通道活性。孟加拉玫瑰红似乎不影响SR中存在的K+通道。将巯基激活的106-kDa Ca2+通道蛋白重组到双层膜中后，孟加拉玫瑰红以光依赖的方式激活分离出的蛋白。浓度为10 nM的ryanodine可使106-kDa通道蛋白锁定在亚电导状态，随后添加500 nM孟加拉玫瑰红可使其逆转。在测量[3H]ryanodine与连接肌浆网（JSR）囊泡的结合时，也直接观察到纳摩尔浓度的孟加拉玫瑰红对结合的ryanodine的明显置换。这些观察结果表明，孟加拉玫瑰红的光氧化通过与ryanodine结合位点相互作用，刺激骨骼肌肌浆网中的Ca2+释放蛋白。此外，孟加拉玫瑰红对分离的SR囊泡、SR囊泡融合后的单通道测量以及分离的106-kDa蛋白掺入后的类似作用，强烈表明106-kDa巯基激活的Ca2+通道蛋白参与了Ca2+释放过程。
