Specificity of inositol trisphosphate-induced calcium release from permeabilized Swiss-mouse 3T3 cells.
Specificity of inositol trisphosphate-induced calcium release from permeabilized Swiss-mouse 3T3 cells.
复制标题
肌醇三磷酸诱导透化瑞士小鼠 3T3 细胞钙释放的特异性。
作者：
R. Irvine;K. Brown;M. Berridge
用皂苷透化的瑞士小鼠 3T3 细胞用于研究三磷酸肌醇诱导的细胞内储存释放 45Ca2+ 的特异性。肌醇 1,4,5-三磷酸是研究中最有效的化合物（半最大效应剂量为 0.3 µM）。肌醇 2,4,5-三磷酸、甘油磷酸肌醇 4,5-二磷酸和肌醇 4,5-二磷酸也可释放 45Ca2+，剂量分别为 1.6 µM、1.6 µM 和 20 µM，但肌醇 1,4-二磷酸 (50 µM) 则不释放 45Ca2+。这些数据表明，4-位和5-位上的跨邻位磷酸盐对于三磷酸肌醇的Ca2+动员作用至关重要，此外，分子另一侧还需要磷酸基团，优先选择1-位。
Swiss-mouse 3T3 cells permeabilized with saponin were used to study the specificity of the inositol trisphosphate-induced release of 45Ca2+ from their intracellular stores. Inositol 1,4,5-trisphosphate was the most potent compound studied (dose giving half-maximal effect 0.3 microM). 45Ca2+ was also released by inositol 2,4,5-trisphosphate, glycerophosphoinositol 4,5-bisphosphate and inositol 4,5-bisphosphate, with doses giving half-maximal effect of respectively 1.6 microM, 1.6 microM and 20 microM, but not by inositol 1,4-bisphosphate (50 microM). These data suggest that the trans-vicinal phosphates on the 4- and 5-positions are essential for the Ca2+-mobilizing effect of inositol trisphosphate, and that in addition there is a requirement for a phosphate group on the opposite side of the molecule, with a preference for the 1-position.