Cabrera J L, de Freitas F, Satpaev D K, Slepak V Z
Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, Florida 33136, USA.
Biochem Biophys Res Commun. 1998 Aug 28;249(3):898-902. doi: 10.1006/bbrc.1998.9218.
The G protein beta subunit G beta 5 deviates significantly from the four other members of the G beta family in amino acid sequence, unique expression pattern (only in the CNS), and cytosolic localization. To identify the members of the G beta 5-mediated signaling pathway, we purified the native protein complex containing G beta 5 from the cytosolic fraction of bovine retina. Analysis of the isolated complex revealed that G beta 5 is tightly associated with RGS7, a member of the superfamily of negative regulators of G protein signaling. This finding, for the first time, demonstrates an interaction between a G beta subunit and an RGS protein. G beta 5 was not detected in the outer segments of photoreceptor cells, suggesting that the cytosolic G beta 5-RGS7 complex is not directly involved in phototransduction.
G蛋白β亚基Gβ5在氨基酸序列、独特的表达模式（仅在中枢神经系统中）和胞质定位方面与Gβ家族的其他四个成员有显著差异。为了鉴定Gβ5介导的信号通路的成员，我们从牛视网膜的胞质部分纯化了含有Gβ5的天然蛋白复合物。对分离出的复合物的分析表明，Gβ5与RGS7紧密相关，RGS7是G蛋白信号负调节因子超家族的成员。这一发现首次证明了Gβ亚基与RGS蛋白之间的相互作用。在光感受器细胞的外段未检测到Gβ5，这表明胞质中的Gβ5-RGS7复合物不直接参与光转导。
