Homologous and heterologous phosphorylation of the vasopressin V1a receptor
Homologous and heterologous phosphorylation of the vasopressin V1a receptor
复制标题
DOI：
10.1016/s0898-6568(99)00035-2
复制
发表时间：
1999-10-01
影响因子：
4.8
通讯作者：
Morel, A
中科院分区：
文献类型：
--
作者：
Ancellin, N;Preisser, L;Morel, A
加压素V1 a受体经历同源和异源脱敏，其可以通过蛋白激酶C的活化来模拟。提示V1 a受体的磷酸化可能参与了脱敏机制。目前在稳定转染大鼠加压素V1 a受体的HEK 293细胞中研究了这种磷酸化。表位标记的V1 a受体的代谢标记和免疫沉淀证明了一个52 kDa的带和一个92 kDa的带。糖苷酶处理和免疫印迹实验表明，52 kDa的手对应于一个未成熟的未加工的受体蛋白，而92 kDa的带将对应于一个高度糖基化的形式的成熟V1 a受体。细胞暴露于加压素诱导选择性P-32磷酸掺入92-kDa形式的受体。这种同源配体诱导的磷酸化是剂量依赖性的，最大磷酸盐掺入对应于基础水平的四倍。通过卡巴胆碱诱导的Via受体的异源磷酸化刺激内源性磷脂酶C偶联的m3毒蕈碱受体，其幅度是同源磷酸化的一半。这种异源磷酸化与细胞内钙的加压素依赖性增加减少有关。细胞信号11;10：743-751，1999. (C)1999 Elsevier Science Inc.
The vasopressin V1a receptor undergoes homologous and heterologous desensitizations which can be mimicked by activation of protein kinase C. This suggests that phosphorylation of the V1a receptor may he involved in the desensitization mechanisms. Such a phosphorylation was presently investigated in HEK 293 cells stably transfected with rat vasopressin V1a receptor. Metabolic labelling and immunoprecipitation of epitope-tagged V1a receptor evidenced a 52-kDa band and a 92-kDa band. Glycosidase treatments and immunoblotting experiments suggest that the 52-kDa hand corresponds to an immature unprocessed receptor protein, whereas the 92-kDa band would correspond to a highly glycosylated form of the mature V1a receptor. Exposure of the cells to vasopressin induced a selective P-32 phosphate incorporation in the 92-kDa form of the receptor. This homologous ligand-induced phosphorylation was dose dependent with maximal phosphate incorporation corresponding to four times the basal level. Stimulation of the endogenous phospholipase C-coupled m3 muscarinic receptor by carbachol-induced heterologous phosphorylation of the Via receptor whose amplitude was half that of the homologous phosphorylation, This heterologous phosphorylation was associated with a reduced vasopressin-dependent increase in intracellular calcium. CELL SIGNAL 11;10:743-751, 1999. (C) 1999 Elsevier Science Inc.