Nerve growth factor promotes the activation of phosphatidylinositol 3-kinase and its association with the trk tyrosine kinase.
Nerve growth factor promotes the activation of phosphatidylinositol 3-kinase and its association with the trk tyrosine kinase.
复制标题
DOI：
10.1016/s0021-9258(18)41950-3
复制
发表时间：
1992-08
期刊：
影响因子：
--
通讯作者：
S. Soltoff;S. Rabin;L. Cantley;D. Kaplan
中科院分区：
文献类型：
--
作者：
S. Soltoff;S. Rabin;L. Cantley;D. Kaplan
我们研究了参与磷脂酰肌醇3-激酶（PtdIns 3-激酶）在启动信号转导的神经生长因子（NGF）在大鼠嗜铬细胞瘤PC 12细胞系。PtdIns 3-激酶催化肌醇环D-3位磷酸形成磷酸肌醇，并且先前已发现与其他活化蛋白酪氨酸激酶（包括生长因子受体酪氨酸激酶）相关。抗磷酸酪氨酸免疫沉淀物具有PtdIns 3-激酶活性，其在PC 12细胞暴露于NGF（100 ng/ml）5分钟后达到最大值（基础活性的9倍）。由于NGF激活trk原癌基因的蛋白产物gp 140 trk的酪氨酸激酶活性，我们还检查了PtdIns 3-激酶与gp 140 trk的关联。抗gp 140 trk免疫沉淀从NGF刺激的PC 12细胞增加PtdIns 3-激酶活性相比，未刺激的细胞，和更大的增加被检测到在细胞过表达gp 140 trk，表明PtdIns 3-激酶协会与gp 140 trk。在用[32 P]正磷酸盐标记的PC 12细胞中，NGF使[32 P]磷脂酰肌醇3，4-二磷酸和[32 P]磷脂酰肌醇3，4，5-三磷酸大量增加，表明完整细胞中PtdIns 3-激酶活性增加。使用抗85 kDa PtdIns 3-激酶亚基抗体，我们发现，神经生长因子促进酪氨酸磷酸化的85 kDa的蛋白质和两个接近110 kDa的蛋白质。这些研究表明，神经生长因子激活PtdIns 3-激酶，并促进其与gp 140 trk的协会，也表明，神经生长因子促进PtdIns 3-激酶的85 kDa亚基的酪氨酸磷酸化。因此，PtdIns 3-激酶激活似乎参与分化以及促有丝分裂反应。
We investigated the involvement of phosphatidylinositol 3-kinase (PtdIns 3-kinase) in the initiation of signal transduction by nerve growth factor (NGF) in the rat pheochromocytoma PC12 cell line. PtdIns 3-kinase catalyzes the formation of phosphoinositides with phosphate in the D-3 position of the inositol ring and previously has been found to associate with other activated protein tyrosine kinases, including growth factor receptor tyrosine kinases. Anti-phosphotyrosine immunoprecipitates had PtdIns 3-kinase activity that reached a maximum (9 times the basal activity) after a 5-min exposure of PC12 cells to NGF (100 ng/ml). Since NGF activates the tyrosine kinase activity of gp140trk, the protein product of the trk proto-oncogene, we also examined the association of PtdIns 3-kinase with gp140trk. Anti-gp140trk immunoprecipitates from NGF-stimulated PC12 cells had increased PtdIns 3-kinase activity compared to that of unstimulated cells, and larger increases were detected in cells overexpressing gp140trk, indicating that PtdIns 3-kinase associates with gp140trk. NGF produced large increases in [32P]phosphatidylinositol 3,4-bisphosphate and [32P]phosphatidylinositol 3,4,5-trisphosphate in PC12 cells labeled with [32P]orthophosphate, indicating an increase in PtdIns 3-kinase activity in intact cells. Using an anti-85-kDa PtdIns 3-kinase subunit antibody, we found that NGF promoted the tyrosine phosphorylation of an 85-kDa protein and two proteins close to 110 kDa. These studies demonstrate that NGF activates PtdIns 3-kinase and promotes its association with gp140trk and also show that NGF promotes the tyrosine phosphorylation of the 85-kDa subunit of PtdIns 3-kinase. Thus, PtdIns 3-kinase activation appears to be involved in differentiation as well as mitogenic responses.