Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville VA 22908.
Department of Surgery, James D. Eason Transplant Institute, UTHSC, Memphis, TN 38103.
Mol Biol Cell. 2022 Aug 1;33(9):br15. doi: 10.1091/mbc.E21-06-0283. Epub 2022 Jun 2.
The Chromosome Passenger Complex (CPC) generates chromosome autonomous signals that regulate mitotic events critical for genome stability. Tip60 is a lysine acetyltransferase that is a tumor suppressor and is targeted for proteasomal degradation by oncogenic papilloma viruses. Mitotic regulation requires the localization of the CPC to inner centromeres, which is driven by the Haspin kinase phosphorylating histone H3 on threonine 3 (H3T3ph). Here we describe how Tip60 acetylates histone H3 at lysine 4 (H3K4ac) to block both the H3T3ph writer and the reader to ensure that this mitotic signaling cannot begin before prophase. Specifically, H3K4ac inhibits Haspin phosphorylation of H3T3 and prevents binding of the Survivin subunit to H3T3ph. Tip60 acetylates H3K4 during S/G2 at centromeres. Inhibition of Tip60 allows the CPC to bind centromeres in G2 cells, and targeting of Tip60 to centromeres prevents CPC localization in mitosis. The H3K4ac mark is removed in prophase by HDAC3 to initiate the CPC localization cascade. Together, our results suggest that Tip60 and HDAC3 temporally control H3K4 acetylation to precisely time the targeting of the CPC to inner centromeres.
染色体乘客复合物(CPC)产生染色体自主信号,调节有丝分裂事件,这些事件对基因组稳定性至关重要。Tip60 是一种赖氨酸乙酰转移酶,它是一种肿瘤抑制因子,并且被致癌的乳头瘤病毒靶向进行蛋白酶体降解。有丝分裂调控需要 CPC 定位到内着丝粒,这是由 Haspin 激酶磷酸化组蛋白 H3 的苏氨酸 3(H3T3ph)驱动的。在这里,我们描述了 Tip60 如何通过乙酰化组蛋白 H3 的赖氨酸 4(H3K4ac)来阻断 H3T3ph 的writer 和 reader,以确保在前期之前不能开始这种有丝分裂信号。具体来说,H3K4ac 抑制 Haspin 对 H3T3 的磷酸化,并阻止 Survivin 亚基与 H3T3ph 的结合。Tip60 在着丝粒处的 S/G2 期间乙酰化 H3K4。Tip60 的抑制允许 CPC 在 G2 细胞中结合着丝粒,并且将 Tip60 靶向到着丝粒可以防止 CPC 在有丝分裂中定位。在前期,H3K4ac 标记被 HDAC3 去除,以启动 CPC 定位级联。总之,我们的结果表明,Tip60 和 HDAC3 从时间上控制 H3K4 乙酰化,以精确地将 CPC 靶向到内着丝粒。