McDonald P H, Chow C W, Miller W E, Laporte S A, Field M E, Lin F T, Davis R J, Lefkowitz R J
Howard Hughes Medical Institute and Department of Medicine, Duke University Medical Center, Box 3821, Durham, NC 27710, USA.
Science. 2000 Nov 24;290(5496):1574-7. doi: 10.1126/science.290.5496.1574.
beta-Arrestins, originally discovered in the context of heterotrimeric guanine nucleotide binding protein-coupled receptor (GPCR) desensitization, also function in internalization and signaling of these receptors. We identified c-Jun amino-terminal kinase 3 (JNK3) as a binding partner of beta-arrestin 2 using a yeast two-hybrid screen and by coimmunoprecipitation from mouse brain extracts or cotransfected COS-7 cells. The upstream JNK activators apoptosis signal-regulating kinase 1 (ASK1) and mitogen-activated protein kinase (MAPK) kinase 4 were also found in complex with beta-arrestin 2. Cellular transfection of beta-arrestin 2 caused cytosolic retention of JNK3 and enhanced JNK3 phosphorylation stimulated by ASK1. Moreover, stimulation of the angiotensin II type 1A receptor activated JNK3 and triggered the colocalization of beta-arrestin 2 and active JNK3 to intracellular vesicles. Thus, beta-arrestin 2 acts as a scaffold protein, which brings the spatial distribution and activity of this MAPK module under the control of a GPCR.
β抑制蛋白最初是在异源三聚体鸟嘌呤核苷酸结合蛋白偶联受体（GPCR）脱敏的背景下被发现的，它在这些受体的内化和信号传导中也发挥作用。我们通过酵母双杂交筛选以及从小鼠脑提取物或共转染的COS-7细胞中进行免疫共沉淀，鉴定出c-Jun氨基末端激酶3（JNK3）是β抑制蛋白2的结合伴侣。还发现上游JNK激活剂凋亡信号调节激酶1（ASK1）和丝裂原活化蛋白激酶（MAPK）激酶4与β抑制蛋白2形成复合物。细胞转染β抑制蛋白2导致JNK3在胞质中滞留，并增强了ASK1刺激的JNK3磷酸化。此外，血管紧张素II 1A型受体的刺激激活了JNK3，并引发β抑制蛋白2和活性JNK3共定位于细胞内小泡。因此，β抑制蛋白2作为一种支架蛋白，使该MAPK模块的空间分布和活性受GPCR的控制。
