14-3-3 proteins interact with specific MEK kinases
14-3-3 proteins interact with specific MEK kinases
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DOI：
10.1074/jbc.273.6.3476
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发表时间：
1998-02-06
影响因子：
4.8
通讯作者：
Vaillancourt, RR
中科院分区：
文献类型：
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作者：
Fanger, GR;Widmann, C;Vaillancourt, RR
MEK（丝裂原活化蛋白激酶/细胞外信号调节激酶激酶）激酶（MEKKs）调节c-Jun N-末端激酶和细胞外应答激酶途径。14-3-3 ζ和14-3-3 ζ同种型在双杂交筛选与MEKK 3的N-末端调节结构域相互作用的蛋白质中分离。14-3-3蛋白结合MEKK 3的N-末端调节和C-末端激酶结构域。14-3-3对MEKK 3 N末端的结合亲和力为90 nM，表明具有高亲和力相互作用。14-3-3蛋白也与MEKK 1和MEKK 2相互作用，但不与MEKK 4相互作用。内源性14-3-3蛋白和MEKK 1和MEKK 2在细胞中的分布相似，与它们在体外的相互作用一致。使用双色数字共聚焦免疫荧光共定位MEKK 1和14-3-3蛋白。14-3-3蛋白与196-kDa MEKK 1 N-末端393个残基的结合。与MEKK 2和MEKK 3不同，MEKK 1的C-末端激酶结构域表现出很少或没有与14-3-3蛋白相互作用的能力。MEKK 1，而不是MEKK 2、-3或-4，是半胱天冬酶-3底物，当切割时从N-末端调节结构域释放激酶结构域。在功能上，半胱天冬酶-3切割MEKK 1从N-末端14-3-3-结合区释放激酶结构域，表明半胱天冬酶可以选择性地改变蛋白激酶与调节蛋白的相互作用。关于MEKK 1、-2和-3，14-3-3蛋白似乎不直接影响活性，而是充当蛋白质-蛋白质相互作用的“支架”。
MEK (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase) kinases (MEKKs) regulate c-Jun N-terminal kinase and extracellular response kinase pathways. The 14-3-3 zeta and 14-3-3 epsilon isoforms were isolated in a two-hybrid screen for proteins interacting with the N-terminal regulatory domain of MEKK3. 14-3-3 proteins bound both the N-terminal regulatory and C-terminal kinase domains of MEKK3. The binding affinity of 14-3-3 for the MEKK3 N terminus was 90 nM, demonstrating a high affinity interaction. 14-3-3 proteins also interacted with MEKK1 and MEKK2, but not MEKK4. Endogenous 14-3-3 protein and MEKK1 and MEKK2 were similarly distributed in the cell, consistent with their in vitro interactions. MEKK1 and 14-3-3 proteins colocalized using two color digital confocal immunofluorescence. Binding of 14-3-3 proteins mapped to the N-terminal 393 residues of 196-kDa MEKK1. Unlike MEKK2 and MEKK3, the C-terminal kinase domain of MEKK1 demonstrated little or no ability to interact with 14-3-3 proteins. MEKK1, but not MEKK2, -3 or -4, is a caspase-3 substrate that when cleaved releases the kinase domain from the N-terminal regulatory domain. Functionally, caspase-3 cleavage of MEKK1 releases the kinase domain from the N-terminal 14-3-3-binding region, demonstrating that caspases can selectively alter protein kinase interactions with regulatory proteins. With regard to MEKK1, -2 and -3, 14-3-3 proteins do not appear to directly influence activity, but rather function as "scaffolds" for protein-protein interactions.