Epidermal growth factor stimulates tyrosine phosphorylation of phospholipase C-II independently of receptor internalization and extracellular calcium.
Epidermal growth factor stimulates tyrosine phosphorylation of phospholipase C-II independently of receptor internalization and extracellular calcium.
复制标题
表皮生长因子刺激磷脂酶 C-II 的酪氨酸磷酸化，独立于受体内化和细胞外钙。
DOI：
10.1073/pnas.86.5.1568
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发表时间：
1989
影响因子：
11.1
通讯作者：
Carpenter,G
中科院分区：
文献类型：
--
作者：
Wahl,MI;Nishibe,S;Suh,PG;Rhee,SG;Carpenter,G
表皮生长因子（EGF）在多种细胞类型中快速刺激肌醇1，4，5-三磷酸的形成。以前，我们已经发现，在完整的细胞刺激磷脂酶C（PLC）的活性EGF与保留增加量的PLC活性的磷酸酪氨酸免疫亲和矩阵，这表明EGF受体酪氨酸激酶磷酸化PLC。我们现在定义的机制，EGF除了A-431细胞刺激PLC活性的磷酸酪氨酸免疫隔离的参数，并证明，EGF除了A-431细胞增加PLC的酪氨酸磷酸化。EGF快速和可逆地刺激增加PLC活性的抗磷酸酪氨酸恢复时，细胞用生长因子在3摄氏度处理，表明受体内化是不需要的，磷酸化事件发生之前，形成肌醇1，4，5-三磷酸。此外，EGF刺激PLC活性的抗磷酸酪氨酸恢复发生在细胞外Ca 2+的情况下。其他激动剂，如缓激肽或ATP，在完整的细胞中的PLC活性的刺激，并没有导致增加的抗磷酸酪氨酸恢复PLC活性，这表明两个独立的机制存在于A-431细胞中的肌醇磷酸盐的形成的酶刺激。最后，使用单克隆抗体，特异性地识别三种不同的PLC同工酶，我们表明，约145 kDa的PLC同工酶（PLC-II）是存在于A-431细胞和EGF治疗的A-431细胞刺激磷酸化PLC-II的酪氨酸和丝氨酸残基。
Epidermal growth factor (EGF) rapidly stimulates the formation of inositol 1,4,5-trisphosphate in a variety of cell types. Previously we have found that in intact cells stimulation of phospholipase C (PLC) activity by EGF is correlated with the retention of increased amounts of PLC activity by a phosphotyrosine immunoaffinity matrix, suggesting that the EGF-receptor tyrosine kinase phosphorylates PLC. We now define parameters of the mechanism by which EGF addition to A-431 cells stimulates phosphotyrosine immunoisolation of PLC activity and demonstrate that EGF addition to A-431 cells increases tyrosine phosphorylation of PLC. EGF rapidly and reversibly stimulated the anti-phosphotyrosine recovery of increased PLC activity when cells were treated with growth factor at 3 degrees C, indicating that receptor internalization is not required and that the phosphorylation event occurs prior to formation of inositol 1,4,5-trisphosphate. Also, the EGF stimulation of anti-phosphotyrosine recovery of PLC activity occurred in the absence of extracellular Ca2+. Stimulation of PLC activity in intact cells by other agonists, such as bradykinin or ATP, did not result in increased anti-phosphotyrosine recovery of PLC activity, suggesting two separate mechanisms exist in A-431 cells for hormone-stimulated formation of inositol phosphates. Finally, using monoclonal antibodies that specifically recognize three distinct PLC isozymes, we show that an approximately 145-kDa PLC isozyme (PLC-II) is present in A-431 cells and that EGF treatment of A-431 cells stimulates phosphorylation of PLC-II on both tyrosine and serine residues.