Raf-1 and p21v-ras cooperate in the activation of mitogen-activated protein kinase.
Raf-1 and p21v-ras cooperate in the activation of mitogen-activated protein kinase.
复制标题
Raf-1 和 p21v-ras 协同激活丝裂原激活蛋白激酶。
DOI：
10.1073/pnas.90.12.5772
复制
发表时间：
1993
影响因子：
11.1
通讯作者：
Roberts,TM
中科院分区：
文献类型：
--
作者：
Williams,NG;Paradis,H;Agarwal,S;Charest,DL;Pelech,SL;Roberts,TM
丝裂原激活蛋白 (MAP) 激酶 Raf-1、pp60src 和 p21ras 在信号从细胞表面到细胞核的传递中都发挥着重要作用。我们使用杆状病毒/Sf9昆虫细胞系统阐明了pp60v-src、p21v-ras、MAP激酶(p44erk1/mapk)和Raf-1之间的调控关系。在 Sf9 细胞中，p44erk1/mapk 通过与 v-Raf 或组成型激活形式的 Raf-1 (Raf22W) 共表达而被激活。相比之下，p44erk1/mapk 仅通过与 Raf-1 或 p21v-ras 单独共表达而在有限程度上被激活。 p44erk1/mapk 的这种激活通过与 p21v-ras 和 Raf-1 共表达而大大增强。由于我们之前已经证明 p21v-ras 刺激 Raf-1 活性，因此 p21v-ras 对 p44erk1/mapk 的激活可能仅通过 Raf-1 依赖性途径发生。然而，Raf-1 (Raf301) 的显性抑制突变体不会阻止 p21-v-ras 对 p44erk1/mapk 的激活。此外，pp60v-src 至少与 p21v-ras 一样有效地激活 Raf-1，但与 Raf-1 共表达时，无法显着增强 p44erk1/mapk 活性。这些数据表明 p21v-ras 对 p44erk1/mapk 的激活可能通过 Raf-1 依赖性和 Raf-1 独立途径发生。
Mitogen-activated protein (MAP) kinases Raf-1, pp60src, and p21ras all play important roles in the transfer of signals from the cell surface to the nucleus. We have used the baculovirus/Sf9 insect cell system to elucidate the regulatory relationships between pp60v-src, p21v-ras, MAP kinase (p44erk1/mapk), and Raf-1. In Sf9 cells, p44erk1/mapk is activated by coexpression with either v-Raf or a constitutively activated form of Raf-1 (Raf22W). In contrast, p44erk1/mapk is activated to only a limited extent by coexpression with either Raf-1 or p21v-ras alone. This activation of p44erk1/mapk is greatly enhanced by coexpression with both p21v-ras and Raf-1. Since we have previously shown that p21v-ras stimulates Raf-1 activity, the activation of p44erk1/mapk by p21v-ras may occur exclusively via a Raf-1-dependent pathway. However, a dominant-inhibitory mutant of Raf-1 (Raf301) does not block the activation of p44erk1/mapk by p21-v-ras. Further, pp60v-src, which activates Raf-1 at least as effectively as p21v-ras, fails to enhance p44erk1/mapk activity greatly when coexpressed with Raf-1. These data suggest that activation of p44erk1/mapk by p21v-ras may occur via both Raf-1-dependent and Raf-1-independent pathways.