Snyder S H, Supattapone S
Department of Neuroscience, John Hopkins University School of Medicine, Baltimore, Maryland.
Cell Calcium. 1989 Jul;10(5):337-42. doi: 10.1016/0143-4160(89)90059-6.
We have identified an IP3 receptor protein in brain membranes through the binding of radiolabelled IP3. Autoradiographic studies localize the receptor to various areas of the brain with highest densities in Purkinje cells of the cerebellum. IP3 binding is inhibited by physiologic intracellular concentrations of calcium. Purification of the IP3 receptor to homogeneity reveals it to be comprised of four identical subunits of 260 kD each. Antisera to the purified receptor protein have been employed for immunohistochemical studies which, at the electron microscopic level, localize the IP3 receptor to a subdivision of the rough endoplasmic reticulum occurring in synaptic areas and in close association with the nuclear membrane. The IP3 receptor protein is selectively phosphorylated by cyclic AMP (cAMP) dependent protein kinase. This phosphorylation decreases 10-fold the potency of IP3 in releasing calcium from brain membranes.
我们通过放射性标记的肌醇三磷酸（IP3）的结合，在脑膜中鉴定出一种IP3受体蛋白。放射自显影研究将该受体定位于大脑的各个区域，在小脑的浦肯野细胞中密度最高。生理细胞内钙浓度可抑制IP3的结合。将IP3受体纯化至同质状态后发现，它由四个相同的260 kD亚基组成。针对纯化后的受体蛋白制备的抗血清已用于免疫组织化学研究，在电子显微镜水平上，这些研究将IP3受体定位于突触区域中粗面内质网的一个亚区，且与核膜紧密相连。IP3受体蛋白被环磷酸腺苷（cAMP）依赖性蛋白激酶选择性磷酸化。这种磷酸化使IP3从脑膜释放钙的能力降低了10倍。
