Castelli Marco, Camps Montserrat, Gillieron Corine, Leroy Didier, Arkinstall Steve, Rommel Christian, Nichols Anthony
Serono Pharmaceutical Research Institute, Serono International S.A., Plan-les-Ouates 1228, Geneva CH1228, Switzerland.
J Biol Chem. 2004 Oct 22;279(43):44731-9. doi: 10.1074/jbc.M407669200. Epub 2004 Jul 28.
Mitogen-activated protein (MAP) kinases play a central role in controlling a wide range of cellular functions following their activation by a variety of extracellular stimuli. MAP kinase phosphatases (MKPs) represent a subfamily of dual specificity phosphatases, which negatively regulate MAP kinases. Although ERK2 activity is regulated by its phosphorylation state, MKP3 is regulated by physical interaction with ERK2, independent of its enzymatic activity (Camps, M., Nichols, A., Gillieron, C., Antonsson, B., Muda, M., Chabert, C., Boschert, U., and Arkinstall, S., (1998) Science 280, 1262-1265; Farooq, A., Chaturvedi, G., Mujtaba, S., Plotnikova, O., Zeng, L., Dhalluin, C., Ashton, R., and Zhou, M. M. (2001), Mol. Cell 7, 387-399; Zhou, B., and Zhang, Z. Y. (1999) J. Biol. Chem. 274, 35526-35534). The interaction of ERK2 and MKP3 allows the reciprocal cross-regulation of their catalytic activity. Indeed, MKP3 acts as a negative regulator on ERK2-MAP kinase signal transduction activity, representing thus a negative feedback for this MAPK pathway. To identify novel proteins able to complex MKP3, we used the yeast two-hybrid system. Here we report that MKP3 and protein kinase CK2 form a protein complex, which can include ERK2. The phosphatase activity of MKP3 is then slightly increased in vitro, whereas in transfected cells, ERK2 dephosphorylation is reduced. In addition, we demonstrated that CK2 selectively phosphorylates MKP3, suggesting cross-regulation between CK2alpha and MKP3, as well as a modulation of ERK2-MAPK signaling by CK2alpha via MKP3.
丝裂原活化蛋白（MAP）激酶在被多种细胞外刺激激活后，在控制广泛的细胞功能中发挥核心作用。MAP激酶磷酸酶（MKPs）代表双特异性磷酸酶的一个亚家族，其对MAP激酶起负调控作用。尽管ERK2的活性受其磷酸化状态调节，但MKP3是通过与ERK2的物理相互作用来调节的，与其酶活性无关（坎普斯，M.，尼科尔斯，A.，吉利隆，C.，安托松，B.，穆达，M.，沙贝尔，C.，博舍特，U.，和阿金斯托尔，S.，（1998年）《科学》280卷，第1262 - 1265页；法鲁克，A.，查图尔维迪，G.，穆贾塔巴，S.，普洛特尼科娃，O.，曾，L.，达卢因，C.，阿什顿，R.，和周，M.M.（2001年），《分子细胞》7卷，第387 - 399页；周，B.，和张，Z.Y.（1999年）《生物化学杂志》274卷，第35526 - 35534页）。ERK2与MKP3的相互作用允许它们的催化活性进行相互交叉调节。实际上，MKP3对ERK2 - MAP激酶信号转导活性起负调控作用，因此代表了该MAPK途径的负反馈。为了鉴定能够与MKP3形成复合物的新蛋白质，我们使用了酵母双杂交系统。在此我们报告MKP3与蛋白激酶CK2形成一种蛋白质复合物，该复合物可以包括ERK2。然后MKP3的磷酸酶活性在体外略有增加，而在转染细胞中，ERK2的去磷酸化减少。此外，我们证明CK2选择性地磷酸化MKP3，表明CK2α与MKP3之间存在交叉调节，以及CK2α通过MKP3对ERK2 - MAPK信号传导的调节作用。
