GTPase-activating protein interactions with the viral and cellular Src kinases.
GTPase-activating protein interactions with the viral and cellular Src kinases.
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GTP 酶激活蛋白与病毒和细胞 Src 激酶相互作用。
DOI：
10.1073/pnas.88.3.755
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发表时间：
1991
影响因子：
11.1
通讯作者：
Jove,R
中科院分区：
文献类型：
--
作者：
Brott,BK;Decker,S;Shafer,J;Gibbs,JB;Jove,R
GTP酶激活蛋白(GAP)调节RAS蛋白的活性，参与生长因子受体和具有酪氨酸激酶活性的癌蛋白的有丝分裂信号转导。在Rous肉瘤病毒中编码的致癌病毒Src(p60v-src)与其非致癌的正常同源物细胞Src(p60c-src)相比具有更高的酪氨酸激酶活性。为了研究GAP和两种Src激酶之间的分子相互作用，以抗GAP或Src的抗体为探针，用凝胶电泳法对从细胞晶状体中制备的Src或GAP的免疫沉淀物进行了分析。结果表明，p60c-src与正常大鼠和鸡细胞裂解物中含有GAP的复合体有关。然而，在经历体外激酶反应的p60c-src免疫沉淀物中，GAP不被磷酸化。相反，当转化细胞裂解物制备的p60v-src免疫沉淀物与ATP孵育时，GAP在体外经历酪氨酸磷酸化。我们的发现表明，p60v-src和p60c-src与含有GAP的复合体结合，并在这两种信号转导途径之间提供了一种生化联系。这些结果与GAP在调节p60c-src的正常功能以及p60v-src的致癌活性中的作用的假设是一致的。
GTPase-activating protein (GAP), which regulates the activities of Ras proteins, is implicated in mitogenic signal transduction by growth-factor receptors and oncoproteins with tyrosine kinase activity. Oncogenic viral Src (p60v-src) encoded in Rous sarcoma virus possesses elevated tyrosine kinase activity compared with its nononcogenic normal homolog, cellular Src (p60c-src). To examine molecular interactions between GAP and the two Src kinases, immunoprecipitates of Src or GAP prepared from cell lystates were resolved by gel electrophoresis and analyzed by an immunoblot procedure with antibodies to GAP or Src used as probes. Results suggest that p60c-src is associated with a complex containing GAP in immunoprecipitates from lysates of normal rat and chicken cells. However, GAP is not phosphorylated in p60c-src immunoprecipitates subjected to in vitro kinase reactions. By contrast, GAP undergoes tyrosyl phosphorylation in vitro when immunoprecipitates of p60v-src prepared from transformed cell lysates are incubated with ATP. Our findings suggest that p60v-src and p60c-src associate with complexes containing GAP and provide a biochemical link between both kinases and GAP/Ras signal transduction pathways. These results are consistent with the hypothesis that GAP has a role in mediating normal functions of p60c-src as well as oncogenic activities of p60v-src.