MEK kinase activity is not necessary for Raf-1 function
MEK kinase activity is not necessary for Raf-1 function
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DOI：
10.1093/emboj/20.8.1940
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发表时间：
2001-04-17
期刊：
影响因子：
11.4
通讯作者：
Pritchard, C
中科院分区：
文献类型：
--
作者：
Hüser, M;Luckett, J;Pritchard, C
Raf- 1蛋白激酶已被确定为哺乳动物Ras/Raf/MEK/ERK信号通路的一个组成部分。Raf-l的激活是通过Ras、GTP结合和质膜上的其他事件实现的，包括340/341残基的酪氨酸磷酸化。我们已经使用基因靶向技术在小鼠中产生了Raf-l基因的“敲除”，以及内源性Raf-l的rafFF突变版本，具有Y340FY341F突变。Raf-1（-/-）小鼠在胚胎发生过程中死亡，卵黄囊和胎盘出现血管缺损，胚胎组织凋亡增加。细胞增殖不受影响。来自FF/FF小鼠的细胞中的raf-1在体外对MEK没有可检测到的活性，然而af-1（FF/FF）小鼠存活到成年，具有生殖力并且具有明显正常的表型。在来自af-1（-/-）和af-1（FF/FF）小鼠的细胞中，ERK激活是正常的。这些结果有力地证明了raf - 1的MEK激酶活性对正常小鼠发育并不是必需的，而raf - 1在防止细胞凋亡中起着关键作用。
Raf-l protein kinase has been identified as an integral component of the Ras/Raf/MEK/ERK signalling pathway in mammals. Activation of Raf-l is achieved by Ras,GTP binding and other events at the plasma membrane including tyrosine phosphorylation at residues 340/341, We have used gene targeting to generate a 'knockout' of the raf-l gene in mice as well as a rafFF mutant version of endogenous Raf-l with Y340FY341F mutations. Raf-1(-/-) mice die in embryogenesis and show vascular defects in the yolk sac and placenta as well as increased apoptosis of embryonic tissues. Cell proliferation is not affected. Raf-l from cells derived from raf-1(FF/FF) mice has no detectable activity towards MEK in vitro, and yet raf-1(FF/FF) mice survive to adulthood, are fertile and have an apparently normal phenotype, In cells derived from both the raf-1(-/-) and raf-1(FF/FF) mice, ERK activation is normal. These results strongly argue that MEK kinase activity of Raf-l is not essential for normal mouse development and that Raf-l plays a key role in preventing apoptosis.