Docking sites on mitogen-activated protein kinase (MAPK) kinases, MAR phosphatases and the Elk-1 transcription factor compete for MAPK binding and are crucial for enzymic activity
Docking sites on mitogen-activated protein kinase (MAPK) kinases, MAR phosphatases and the Elk-1 transcription factor compete for MAPK binding and are crucial for enzymic activity
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DOI：
10.1042/bj20021806
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发表时间：
2003-03-15
影响因子：
4.1
通讯作者：
Bardwell, L
中科院分区：
文献类型：
--
作者：
Bardwell, AJ;Abdollahi, M;Bardwell, L
丝裂原激活蛋白激酶 (MAPK) 级联控制响应细胞外刺激的基因表达模式。 MAPK/ ERK（细胞外信号调节激酶）激酶 (MEK) 通过磷酸化 MAPK 来激活 MAPK；激活的 MAPK 反过来会磷酸化靶转录因子，并被磷酸酶失活。维持信号特异性和效率的一种机制是 MAPK 通过高亲和力对接位点与其底物和调节剂相互作用。在本研究中，我们发现与 MEK1、MEK2、Ste7、Elk-I 和 MAPK 磷酸酶 (MKP)-2 的 MAPK 对接位点相对应的肽可有效抑制 ERK2 的 MEK2 磷酸化、Elk-1 的 ERK2 磷酸化和 ERK2 的 MKP-1 去磷酸化。每种肽抑制多种反应；例如，MEK2肽不仅抑制MEK2，还抑制ERK2和MKP-1。此外，这些对接位点肽抑制 MEK2-ERK2 结合。 MEK1 的 MAPK 对接位点也有效刺激 ERK2 介导的同一肽上靶位点的磷酸化。具有 MAPK 对接位点共有保守碱性和疏水残基突变的对照肽缺乏生物活性。我们得出的结论是，MEK、MKP 和 Elk-1 转录因子通过蛋白质-蛋白质相互作用竞争结合 ERK2 的同一区域，这对激酶/磷酸酶活性至关重要。
Mitogen-activated protein kinase (MAPK) cascades control gene expression patterns in response to extracellular stimuli. MAPK/ ERK (extracellular-signal-regulated kinase) kinases (MEKs) activate MAPKs by phosphorylating them; activated MAPKs, in turn, phosphorylate target transcription factors, and are deactivated by phosphatases. One mechanism for maintaining signal specificity and efficiency is the interaction of MAPKs with their substrates and regulators through high-affinity docking sites. In the present study, we show that peptides corresponding to the MAPK-docking sites of MEK1, MEK2, Ste7, Elk-I and MAPK phosphatase (MKP)-2 potently inhibit MEK2 phosphorylation of ERK2, ERK2 phosphorylation of Elk-1, and MKP-1 dephosphorylation of ERK2. Each peptide inhibited multiple reactions; for example, the MEK2 peptide inhibited not only MEK2, but also ERK2 and MKP-1. In addition, these docking-site peptides inhibited MEK2-ERK2 binding. The MAPK-docking site of MEK1 also potently stimulated ERK2-mediated phosphorylation of a target site on the same peptide. Control peptides with mutations of conserved basic and hydrophobic residues of the MAPK-docking site consensus lacked biological activity. We conclude that MEKs, MKPs and the Elk-1 transcription factor compete for binding to the same region of ERK2 via protein-protein interactions that are crucial for kinase/phosphatase activity.