Deletions within the amino-terminal half of the c-src gene product that alter the functional activity of the protein.
Deletions within the amino-terminal half of the c-src gene product that alter the functional activity of the protein.
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c-src 基因产物氨基末端的一半缺失会改变蛋白质的功能活性。
DOI：
10.1128/mcb.9.3.1109-1119.1989
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发表时间：
1989
影响因子：
5.3
通讯作者：
Brugge,JS
中科院分区：
文献类型：
--
作者：
Nemeth,SP;Fox,LG;DeMarco,M;Brugge,JS
为了研究pp 60 c-src催化结构域之外的氨基酸序列如何影响该蛋白的功能活性，我们在pp 60 c-src氨基末端的一半内引入了缺失突变。这些突变引起c-src基因产物的生化特性和携带这些突变c-src基因的逆转录病毒感染的细胞的特性的明显变化。表达c-srcNX蛋白的细胞，其中含有氨基酸15至89的缺失，显示出一种无活性的，纺锤形的形态，在软琼脂中形成中等大小的，紧密堆积的菌落，并含有升高水平的细胞含磷酸酪氨酸的蛋白。因此，氨基酸15至89的缺失可以激活c-src基因产物的激酶活性和转化潜力。然而，氨基酸112至225的缺失并没有增加pp 60 c-src的激酶活性或转化能力;事实上，c-srcHP中这些序列的缺失抑制了pp 60 c-src诱导的表型改变。表达c-srcNP或c-srcBS基因产物（分别含有氨基酸15至225和55至169的缺失）的细胞显示出梭形、可触变的形态，并在软琼脂中形成弥散集落;突变蛋白显示出体外蛋白酪氨酸激酶活性增加。然而，只有少数细胞蛋白含有体内磷酸酪氨酸水平升高。因此，氨基酸89下游的缺失严重限制了c-src在体内磷酸化细胞底物的能力，而不影响c-src基因产物的固有酪氨酸激酶活性。这些结果表明，存在至少两个调制区域内的氨基端的一半的pp 60 c-src的酪氨酸激酶活性的调节和pp 60 c-src与细胞底物的相互作用是重要的。
To examine how amino acid sequences outside of the catalytic domain of pp60c-srcinfluence the functional activity of this protein, we have introduced deletion mutations within the amino-terminal half of pp60c-src. These mutations caused distinct changes in the biochemical properties of the c-srcgene products and in the properties of cells infected with retroviruses carrying these mutant c-srcgenes. Cells expressing the c-srcNX protein, which contains a deletion of amino acids 15 to 89, displayed a refractile, spindle-shaped morphology, formed intermediate-sized, tightly packed colonies in soft agar, and contained elevated levels of cellular phosphotyrosine-containing proteins. Thus, deletion of amino acids 15 to 89 can activate the kinase activity and transforming potential of the c-srcgene product. Deletion of amino acids 112 to 225, however, did not increase the kinase activity or transforming ability of pp60c-src; indeed, deletion of these sequences in c-srcHP suppressed phenotypic alterations induced by pp60c-src. Cells expressing the c-srcNP or c-srcBS gene products (containing deletions of amino acids 15 to 225 and 55 to 169, respectively) displayed a fusiform, refractile morphology and formed diffuse colonies in soft agar; the mutant proteins displayed an increased in vitro protein-tyrosine kinase activity. However, only a few cellular proteins contained elevated levels of phosphotyrosine in vivo. Thus, deletions downstream of amino acid 89 severely restricted the ability of c-srcto phosphorylate cellular substrates in vivo without affecting the intrinsic tyrosine kinase activity of the c-srcgene product. These results suggest the existence of at least two modulatory regions within the amino-terminal half of pp60c-srcthat are important for the regulation of tyrosine kinase activity and for the interaction of pp60c-srcwith cellular substrates.