The transforming potential of the c-erbB-2 protein is regulated by its autophosphorylation at the carboxyl-terminal domain
The transforming potential of the c-erbB-2 protein is regulated by its autophosphorylation at the carboxyl-terminal domain
复制标题
c-erbB-2 蛋白的转化潜力由其羧基末端结构域的自身磷酸化调节
DOI：
10.1128/mcb.11.2.833-842.1991
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发表时间：
1991
影响因子：
5.3
通讯作者：
Tadashi Yamamoto
中科院分区：
文献类型：
--
作者：
T. Akiyama;Satoru Matsuda;Y. Namba;Toshiyuki Saito;Kumao Toyoshima;Tadashi Yamamoto
以Glu取代瓦尔-659的突变体c-erbB-2蛋白在NIH 3 T3细胞中具有转化活性。该蛋白在体外表现出增强的酪氨酸激酶活性，并增强了位于羧基末端近端的Tyr-1248处的自磷酸化。在表达Glu-659 c-erbB-2蛋白的细胞中检测到几种细胞蛋白的酪氨酸磷酸化增强。在该蛋白的ATP结合位点（Lys-753至Met）引入额外的突变导致其转化能力的消除。这些数据表明，c-erbB-2的转化潜力与基因产物的酪氨酸激酶活性升高密切相关。为了研究自磷酸化在细胞转化中的作用，我们在Glu-659 c-erbB-2蛋白的自磷酸化位点引入了额外的突变（Tyr-1248变为Phe）。该突变蛋白表现出较低的酪氨酸激酶活性和较低的转化活性。另一方面，当从c-erbB-2蛋白质中删除羧基末端230个氨基酸残基时，该蛋白质的酪氨酸激酶活性和细胞转化活性增强。因此，羧基末端结构域，其中包含主要的自磷酸化位点，Tyr-1248，可以负调节细胞转化和自磷酸化可以消除这种负调节。
The mutant c-erbB-2 protein with Glu instead of Val-659 exhibited transforming activity in NIH 3T3 cells. This protein showed enhanced tyrosine kinase activity in vitro and enhanced autophosphorylation at Tyr-1248 located proximal to the carboxyl terminus. Enhanced tyrosine phosphorylation of several cellular proteins was detected in cells expressing the Glu-659 c-erbB-2 protein. Introduction of an additional mutation at the ATP-binding site (Lys-753 to Met) of this protein resulted in abolition of its transforming ability. These data indicate that the transforming potential of c-erbB-2 is closely correlated with elevated tyrosine kinase activity of the gene product. To investigate the role of autophosphorylation in cell transformation, we introduced an additional mutation at the autophosphorylation site of the Glu-659 c-erbB-2 protein (Tyr-1248 to Phe). This mutant protein exhibited lower tyrosine kinase activity and lower transforming activity. On the other hand, when the carboxyl-terminal 230 amino acid residues were deleted from the c-erbB-2 protein, the tyrosine kinase activity and cell-transforming activity of the protein were enhanced. Thus, the carboxyl-terminal domain, which contains the major autophosphorylation site, Tyr-1248, may regulate cellular transformation negatively and autophosphorylation may eliminate this negative regulation.