p42/mitogen-activated protein kinase as a converging target for different growth factor signaling pathways: use of pertussis toxin as a discrimination factor.
p42/mitogen-activated protein kinase as a converging target for different growth factor signaling pathways: use of pertussis toxin as a discrimination factor.
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p42/丝裂原激活蛋白激酶作为不同生长因子信号通路的汇聚靶标：使用百日咳毒素作为区分因素。
DOI：
10.1091/mbc.2.8.675
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Weber,MJ
中科院分区：
文献类型：
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作者：
L'Allemain,G;Pouyssegur,J;Weber,MJ
丝裂原活化蛋白(MAP)是一种42 kDa的丝氨酸/苏氨酸特异性蛋白激酶，需要酪氨酸和苏氨酸残基的磷酸化才能激活。在加入各种激动剂，包括胰岛素、表皮生长因子、血小板衍生生长因子和佛波酯后，这种酶在静止的细胞中被迅速和短暂地激活。我们发现，在CCL39成纤维细胞中加入生长因子凝血酶或碱性成纤维细胞生长因子可迅速诱导P42蛋白酪氨酸磷酸化，同时刺激MAP酶活性。为了阐明这种激活所使用的信号通路，我们利用CCL39细胞对百日咳杆菌毒素的敏感性，ADP-核糖化该细胞系统中的两个Gi蛋白。我们发现，用该毒素预处理细胞可抑制凝血酶对MAP激酶的刺激作用，但对碱性成纤维细胞生长因子的刺激作用不明显。我们还证明了这两个协同促进有丝分裂的生长因子能够协同激活MAP激酶，并且这种协同作用对百日咳毒素部分敏感。最后，我们描述了一个44 kDa的蛋白质，它的酪氨酸磷酸化似乎与p42蛋白激酶协同调节。我们得出结论，p42蛋白激酶(和pp44蛋白)位于或位于两个不同受体诱导的信号通路汇合点的下游，并可能在整合这些信号方面发挥关键作用。
Mitogen-activated protein (MAP) kinase is a 42-kDa serine/threonine-specific protein kinase that requires phosphorylation on both tyrosine and threonine residues for activity. This enzyme is rapidly and transiently activated in quiescent cells after addition of various agonists, including insulin, epidermal growth factor, platelet-derived growth factor, and phorbol esters. We show here that addition of the growth factors thrombin or basic fibroblast growth factor to CCL39 fibroblasts rapidly induces tyrosine phosphorylation of the p42 MAP kinase protein and concomitantly stimulates MAP kinase enzymatic activity. To elucidate the signaling pathways utilized in this activation, we took advantage of the sensitivity of CCL39 cells to the toxin of bordetella pertussis, which ADP-ribosylates two Gi proteins in this cell system. We show that pretreatment of cells with the toxin inhibited thrombin stimulation of MAP kinase by greater than 75% but had no detectable effect on the stimulation induced by basic fibroblast growth factor. We also demonstrate that these two growth factors that synergize for mitogenicity are able to cooperate in activation of MAP kinase and that this synergism is partially sensitive to pertussis toxin. Finally, we describe a 44-kDa protein, the tyrosine phosphorylation of which appears to be coregulated with p42 MAP kinase. We conclude that p42 MAP kinase (and the pp44 protein) are at or are downstream from a point of convergence of two different receptor-induced signaling pathways and might well play a key role in integrating those signals.