State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Rd, Shanghai 200433, China.
BMB Rep. 2009 Dec 31;42(12):840-5. doi: 10.5483/bmbrep.2009.42.12.840.
Mitogen- and stress-activated protein kinase (MSK1) palys a crucial role in the regulation of transcription downstream of extracellular-signal-regulated kinase1/2 (ERK1/2) and mitogen- activated protein kinase p38. MSK1 can be phosphorylated and activated in cells by both ERK1/2 and p38alpha. In this study, Casein Kinase 2 (CK2) was identified as a binding and regulatory partner for MSK1. Using the yeast two-hybrid system, MSK1 was found to interact with the CK2beta regulatory subunit of CK2. Interactions between MSK1 and the CK2alpha catalytic subunit and CK2beta subunit were demonstrated in vitro and in vivo. We further found that CK2alpha can only interact with the C-terminal kinase domain of MSK1. Using site-directed mutagenesis assay and mass spectrometry, we identified five sites in the MSK1 C-terminus that could be phosphorylated by CK2 in vitro: Ser757, Ser758, Ser759, Ser760 and Thr793. Of these, Ser757, Ser759, Ser760 and Thr793 were previously unknown.
有丝分裂原和应激激活蛋白激酶（MSK1）在外源信号调节激酶 1/2（ERK1/2）和丝裂原激活蛋白激酶 p38 下游的转录调控中发挥着关键作用。MSK1 可以通过 ERK1/2 和 p38alpha 磷酸化和激活细胞中的 MSK1。在这项研究中，酪蛋白激酶 2（CK2）被鉴定为 MSK1 的结合和调节伙伴。使用酵母双杂交系统，发现 MSK1 与 CK2 的 CK2beta 调节亚基相互作用。在体外和体内证实了 MSK1 与 CK2alpha 催化亚基和 CK2beta 亚基之间的相互作用。我们进一步发现 CK2alpha 只能与 MSK1 的 C 端激酶结构域相互作用。通过定点突变实验和质谱分析，我们在 MSK1 的 C 端鉴定出五个可以被 CK2 在体外磷酸化的位点：Ser757、Ser758、Ser759、Ser760 和 Thr793。其中，Ser757、Ser759、Ser760 和 Thr793 以前是未知的。
