Dominant-negative mutants of the SH2/SH3 adapters Nck and Grb2 inhibit MAP kinase activation and mesoderm-specific gene induction by eFGF in Xenopus
Dominant-negative mutants of the SH2/SH3 adapters Nck and Grb2 inhibit MAP kinase activation and mesoderm-specific gene induction by eFGF in Xenopus
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DOI：
10.1038/sj.onc.1202158
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发表时间：
1998-10-29
期刊：
影响因子：
8
通讯作者：
Mayer, BJ
中科院分区：
文献类型：
--
作者：
Gupta, RW;Mayer, BJ
SH 2/SH 3衔接子Nck、Grb 2和Crk通过使用其SH 2结构域与酪氨酸磷酸化蛋白结合以及使用其SH 3结构域与效应分子上富含脯氨酸的序列结合来促进信号传导复合物的组装。FGF激活受体酪氨酸激酶，通过激活Ras/Raf/MAPK信号通路诱导非洲爪蟾胚胎中的中胚层形成。我们目前的证据表明，显性负突变体NCK和Grb 2，但不是Crk 1，可以抑制中胚层特异性基因诱导的eFGF在非洲爪蟾动物帽外植体。我们还表明，Grb 2和Nck的显性负突变体可以抑制非洲爪蟾动物帽中的EGF诱导的Erk 1激活，并且将Nck的前两个SH 3结构域靶向膜可以在没有eFGF的情况下激活Erk 1。此外，显性负性Grb 2突变体与抑制性Nck突变体的组合协同抑制Erk 1激活的eFGF在非洲爪蟾动物帽，表明显性负性Nck和Grb 2突变体抑制Erk 1激活通过结合到不同的蛋白质。相比之下，只有Grb 2突变体可以抑制人293细胞中EGF诱导的Erk 1活化，这表明不同细胞中FGF至MAP激酶信号传导的特定机制存在差异。
The SH2/SH3 adapters Nck, Grb2 and Crk promote the assembly of signaling complexes by binding to tyrosine phosphorylated proteins using their SH2 domains and to proline-rich sequences on effector molecules using their SH3 domains. FGF, which activates a receptor tyrosine kinase, induces mesoderm formation in Xenopus embryos through activation of the Ras/Raf/MAPK signaling pathway. We present evidence that dominant-negative mutants of Nck and Grb2, but not Crk1, can inhibit mesoderm-specific gene induction by eFGF in Xenopus animal cap explants. We also show that dominant-negative mutants of Grb2 and Nck can inhibit eFGF-induced Erk1 activation in Xenopus animal caps, and that targeting the first two SH3 domains of Nck to the membrane can activate Erk1 in the absence of eFGF.. Furthermore, combinations of the dominant-negative Grb2 mutants with the inhibitory Nck mutant synergistically inhibited Erk1 activation by eFGF in Xenopus animal caps, suggesting that the dominant-negative Nck and Grb2 mutants inhibit Erk1 activation by binding to different proteins. By contrast only Grb2 mutants could inhibit eFGF-induced Erk1 activation in human 293 cells, demonstrating diversity in the specific mechanisms of signaling from FGF to MAP kinases in different cells.