Zhong S, Jansen C, She Q B, Goto H, Inagaki M, Bode A M, Ma W Y, Dong Z
Hormel Institute, Austin, Minnesota 55912, USA.
J Biol Chem. 2001 Aug 31;276(35):33213-9. doi: 10.1074/jbc.M103973200. Epub 2001 Jul 5.
N-terminal tail phosphorylation of histone H3 plays an important role in gene expression, chromatin remodeling, and chromosome condensation. Phosphorylation of histone H3 at serine 10 was shown to be mediated by RSK2, mitogen- and stress-activated protein kinase-1 (MSK1), and mitogen-activated protein kinases depending on the specific stimulation or stress. Our previous study showed that mitogen-activated protein kinases MAP kinases are involved in ultraviolet B-induced phosphorylation of histone H3 at serine 28 (Zhong, S., Zhong, Z., Jansen, J., Goto, H., Inagaki, M., and Dong, Z., J. Biol. Chem. 276, 12932-12937). However, downstream effectors of MAP kinases remain to be identified. Here, we report that H89, a selective inhibitor of the nucleosomal response, totally inhibits ultraviolet B-induced phosphorylation of histone H3 at serine 28. H89 blocks MSK1 activity but does not inhibit ultraviolet B-induced activation of MAP kinases p70/85(S6K), p90(RSK), Akt, and protein kinase A. Furthermore, MSK1 markedly phosphorylated serine 28 of histone H3 and chromatin in vitro. Transfection experiments showed that an N-terminal mutant MSK1 or a C-terminal mutant MSK1 markedly blocked MSK1 activity. Compared with wild-type MSK1, cells transfected with N-terminal or C-terminal mutant MSK1 strongly blocked ultraviolet B-induced phosphorylation of histone H3 at serine 28 in vivo. These data illustrate that MSK1 mediates ultraviolet B-induced phosphorylation of histone H3 at serine 28.
组蛋白H3的N端尾部磷酸化在基因表达、染色质重塑和染色体凝聚中发挥着重要作用。研究表明，丝氨酸10处的组蛋白H3磷酸化由RSK2、丝裂原和应激激活蛋白激酶-1（MSK1）以及丝裂原激活蛋白激酶介导，具体取决于特定的刺激或应激。我们之前的研究表明，丝裂原激活蛋白激酶参与紫外线B诱导的组蛋白H3丝氨酸28位点的磷酸化（钟，S.，钟，Z.，扬森，J.，后藤，H.，稻垣，M.，和董，Z.，《生物化学杂志》276，12932 - 12937）。然而，丝裂原激活蛋白激酶的下游效应器仍有待确定。在此，我们报告H89，一种核小体反应的选择性抑制剂，完全抑制紫外线B诱导的组蛋白H3丝氨酸28位点的磷酸化。H89阻断MSK1活性，但不抑制紫外线B诱导的丝裂原激活蛋白激酶p70/85(S6K)、p90(RSK)、Akt和蛋白激酶A的激活。此外，MSK1在体外能显著磷酸化组蛋白H3的丝氨酸28和染色质。转染实验表明，N端突变体MSK1或C端突变体MSK1显著阻断MSK1活性。与野生型MSK1相比，用N端或C端突变体MSK1转染的细胞在体内强烈阻断紫外线B诱导的组蛋白H3丝氨酸28位点的磷酸化。这些数据表明，MSK1介导紫外线B诱导的组蛋白H3丝氨酸28位点磷酸化。
