Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
Nucleic Acids Res. 2013 Sep;41(17):8085-93. doi: 10.1093/nar/gkt583. Epub 2013 Jul 4.
Phosphorylation of histone H4 serine 47 (H4S47ph) is catalyzed by Pak2, a member of the p21-activated serine/threonine protein kinase (Pak) family and regulates the deposition of histone variant H3.3. However, the phosphatase(s) involved in the regulation of H4S47ph levels was unknown. Here, we show that three phosphatases (PP1α, PP1β and Wip1) regulate H4S47ph levels and H3.3 deposition. Depletion of each of the three phosphatases results in increased H4S47ph levels. Moreover, PP1α, PP1β and Wip1 bind H3-H4 in vitro and in vivo, whereas only PP1α and PP1β, but not Wip1, interact with Pak2 in vivo. These results suggest that PP1α, PP1β and Wip1 regulate the levels of H4S47ph through directly acting on H4S47ph, with PP1α and PP1β also likely regulating the activity of Pak2. Finally, depletion of PP1α, PP1β and Wip1 leads to increased H3.3 occupancy at candidate genes tested, elevated H3.3 deposition and enhanced association of H3.3 with its chaperones HIRA and Daxx. These results reveal a novel role of three phosphatases in chromatin dynamics in mammalian cells.
组蛋白 H4 丝氨酸 47 位磷酸化（H4S47ph）由 Pak2 催化，Pak2 是 p21 激活的丝氨酸/苏氨酸蛋白激酶（Pak）家族的成员，调节组蛋白变体 H3.3 的沉积。然而，调控 H4S47ph 水平的磷酸酶（s）尚不清楚。在这里，我们表明三种磷酸酶（PP1α、PP1β 和 Wip1）调节 H4S47ph 水平和 H3.3 沉积。三种磷酸酶中的每一种的耗竭都会导致 H4S47ph 水平升高。此外，PP1α、PP1β 和 Wip1 在体外和体内与 H3-H4 结合，而只有 PP1α 和 PP1β，但不是 Wip1，在体内与 Pak2 相互作用。这些结果表明，PP1α、PP1β 和 Wip1 通过直接作用于 H4S47ph 来调节 H4S47ph 的水平，PP1α 和 PP1β 也可能调节 Pak2 的活性。最后，PP1α、PP1β 和 Wip1 的耗竭导致候选基因中 H3.3 占有率增加，H3.3 沉积增加，H3.3 与其伴侣 HIRA 和 Daxx 的结合增强。这些结果揭示了三种磷酸酶在哺乳动物细胞染色质动力学中的新作用。
