MRC Protein Phosphorylation Unit, Sir James Black Complex, University of Dundee, Dundee DD1 5EH, Scotland, U.K.
Biochem J. 2012 Jan 1;441(1):347-57. doi: 10.1042/BJ20110970.
MSK1 (mitogen- and stress-activated kinase 1) and MSK2 are nuclear protein kinases that regulate transcription downstream of the ERK1/2 (extracellular-signal-regulated kinase 1/2) and p38α MAPKs (mitogen-activated protein kinases) via the phosphorylation of CREB (cAMP-response-element-binding protein) and histone H3. Previous studies on the function of MSKs have used two inhibitors, H89 and Ro 31-8220, both of which have multiple off-target effects. In the present study, we report the characterization of the in vitro and cellular properties of an improved MSK1 inhibitor, SB-747651A. In vitro, SB-747651A inhibits MSK1 with an IC50 value of 11 nM. Screening of an in vitro panel of 117 protein kinases revealed that, at 1 μM, SB-747651A inhibited four other kinases, PRK2 (double-stranded-RNA-dependent protein kinase 2), RSK1 (ribosomal S6 kinase 1), p70S6K (S6K is S6 kinase) (p70RSK) and ROCK-II (Rho-associated protein kinase 2), with a similar potency to MSK1. In cells, SB-747651A fully inhibited MSK activity at 5-10 μM. SB-747651A was found to inhibit the production of the anti-inflammatory cytokine IL-10 (interleukin-10) in wild-type, but not MSK1/2-knockout, macrophages following LPS (lipopolysaccharide) stimulation. Both SB-747651A and MSK1/2 knockout resulted in elevated pro-inflammatory cytokine production by macrophages in response to LPS. Comparison of the effects of SB-747651A, both in vitro and in cells, demonstrated that SB-747651A exhibited improved selectivity over H89 and Ro 31-8220 and therefore represents a useful tool to study MSK function in cells.
MSK1（有丝分裂原和应激激活的激酶 1）和 MSK2 是核蛋白激酶，通过磷酸化 CREB（cAMP 反应元件结合蛋白）和组蛋白 H3，调节 ERK1/2（细胞外信号调节激酶 1/2）和 p38α MAPKs（丝裂原激活的蛋白激酶）下游的转录。以前关于 MSKs 功能的研究使用了两种抑制剂，H89 和 Ro 31-8220，它们都有多个非靶点效应。在本研究中，我们报告了一种改进的 MSK1 抑制剂 SB-747651A 的体外和细胞特性的表征。在体外，SB-747651A 对 MSK1 的抑制 IC50 值为 11 nM。对 117 种蛋白激酶的体外筛选表明，在 1 μM 时，SB-747651A 还抑制了另外四种激酶，PRK2（双链 RNA 依赖性蛋白激酶 2）、RSK1（核糖体 S6 激酶 1）、p70S6K（S6K 是 S6 激酶）（p70RSK）和 ROCK-II（Rho 相关蛋白激酶 2），其抑制作用与 MSK1 相似。在细胞中，SB-747651A 在 5-10 μM 时完全抑制 MSK 活性。在 LPS（脂多糖）刺激后，SB-747651A 被发现可抑制野生型而非 MSK1/2 敲除巨噬细胞中抗炎细胞因子 IL-10（白细胞介素-10）的产生。SB-747651A 和 MSK1/2 敲除均导致巨噬细胞对 LPS 的反应中促炎细胞因子的产生增加。在体外和细胞中比较 SB-747651A 的作用表明，与 H89 和 Ro 31-8220 相比，SB-747651A 具有更高的选择性，因此代表了一种研究细胞中 MSK 功能的有用工具。
