Phosphorylation of the human estrogen receptor on tyrosine 537 in vivo and by src family tyrosine kinases in vitro.
Phosphorylation of the human estrogen receptor on tyrosine 537 in vivo and by src family tyrosine kinases in vitro.
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DOI：
10.1210/mend.9.1.7539106
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发表时间：
1995
影响因子：
--
通讯作者：
S. F. Arnold;J. Obourn;H. Jaffe;A. Notides
中科院分区：
文献类型：
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作者：
S. F. Arnold;J. Obourn;H. Jaffe;A. Notides
Western印迹分析表明，人雌激素受体(HER)及其在昆虫细胞中表达的重组HER均被酪氨酸(S)磷酸化。反相高效液相色谱分离Sf9和MCF-7细胞中32P标记的纯化HER的胰酶消化液，然后进行氨基酸和放射性标记测序，结果表明酪氨酸-537是磷酸化的。MCF-7细胞酪氨酸-537的磷酸化与雌二醇的作用无关，提示酪氨酸-537是酪氨酸的基础磷酸化位点。两个src家族酪氨酸激酶，p60c-src和p56lck，在体外使纯化的重组hER在酪氨酸-537上磷酸化。此外，两种酪氨酸磷酸酶，蛋白酪氨酸磷酸酶-1B和src同源-2蛋白酪氨酸磷酸酶-1，去磷酸化酪氨酸-537的HER体外。这些数据表明，HER的酪氨酸磷酸化受潜在的致癌酪氨酸激酶和磷酸酶的调节，这些酶可能调节ER在正常和/或异常细胞生长中的功能。
Its reactivity to the antiphosphotyrosine 4G10 monoclonal antibody by Western blot analysis demonstrated that the human estrogen receptor (hER) from human MCF-7 cells and the recombinant hER expressed in Sf9 insect cells were phosphorylated on tyrosine(s). Reverse phase-HPLC separation of a tryptic digest of the 32P-labeled purified hER from Sf9 and MCF-7 cells followed by amino acid and radiolabel sequencing revealed that tyrosine-537 was phosphorylated. The phosphorylation on tyrosine-537 was independent of estradiol treatment of MCF-7 cells, indicating that tyrosine-537 is a basal phosphorylation site. Two src family tyrosine kinases, p60c-src and p56lck, phosphorylated the purified recombinant hER on tyrosine-537 in vitro. In addition, two tyrosine phosphatases, protein tyrosine phosphatase-1B and src homology-2 protein tyrosine phosphatase-1, dephosphorylated phosphotyrosine-537 of the hER in vitro. These data suggest that tyrosine phosphorylation of the hER is regulated by potentially oncogenic tyrosine kinases and phosphatases that may modulate the function of ER in normal and/or abnormal cell growth.