Activation of phosphotyrosine phosphatase activity by reduction of cell-substrate adhesion.
Activation of phosphotyrosine phosphatase activity by reduction of cell-substrate adhesion.
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通过减少细胞与基质的粘附来激活磷酸酪氨酸磷酸酶活性。
DOI：
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发表时间：
1993
影响因子：
11.1
通讯作者：
Pamela Maher
中科院分区：
文献类型：
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作者：
Pamela Maher
用胰蛋白酶处理鸡胚成纤维细胞（CEFs）导致细胞蛋白磷酸酪氨酸的剂量和时间依赖性损失。在磷酸盐缓冲盐水（PBS）中孵育CEF后，蛋白质酪氨酸磷酸化发生类似但不太明显的减少。用胰蛋白酶或PBS处理后蛋白质的磷酸酪氨酸含量的减少，如通过用抗磷酸酪氨酸抗体对细胞提取物进行免疫印迹所确定的，对应于通过免疫荧光显微镜检测到的在焦点接触处磷酸酪氨酸抗体免疫反应性的损失。细胞蛋白中的磷酸酪氨酸的恢复发生在30分钟内去除胰蛋白酶后，即使在蛋白质合成抑制剂放线菌酮的存在下，这表明含磷酸酪氨酸的蛋白质的损失是不是由于它们的降解胰蛋白酶。用蛋白酪氨酸磷酸酶的抑制剂预处理CEFs大大减少了由胰蛋白酶引起的蛋白质中磷酸酪氨酸的损失。此外，在从胰蛋白酶处理的CEFs制备的提取物中，磷酸酪氨酸磷酸酶活性增加。用胰蛋白酶或PBS处理后蛋白质中磷酸酪氨酸的损失不是CEF特有的，但也在已建立的成纤维细胞系中观察到。总之，这些结果表明，一个或多个磷酸酪氨酸磷酸酶的活性调节细胞基质粘附。
Treatment of chicken embryo fibroblasts (CEFs) with trypsin results in a dose- and time-dependent loss of phosphotyrosine from cellular proteins. A similar, but less marked, reduction in protein tyrosine phosphorylation occurs upon incubation of CEFs in phosphate-buffered saline (PBS). The decrease in the phosphotyrosine content of proteins following treatment with trypsin or PBS, as determined by immunoblotting of cell extracts with anti-phosphotyrosine antibodies, corresponds with a loss of phosphotyrosine antibody immunoreactivity at focal contacts, as detected by immunofluorescence microscopy. The recovery of phosphotyrosine in cellular proteins occurs within 30 min following removal of trypsin, even in the presence of the protein synthesis inhibitor cycloheximide, indicating that the loss of phosphotyrosine-containing proteins is not due to their degradation by trypsin. Pretreatment of CEFs with inhibitors of protein-tyrosine-phosphatases greatly reduces the loss of phosphotyrosine from proteins brought about by trypsin. In addition, phosphotyrosine phosphatase activity is increased in extracts prepared from trypsin-treated CEFs. The loss of phosphotyrosine from proteins following treatment with trypsin or PBS is not specific to CEFs but is also observed in established fibroblast lines. Taken together these results suggest that the activity of one or more phosphotyrosine phosphatases is regulated by cell-substrate adhesion.