可变剪接和别构调节调节 UHRF1 与染色质的结合。
Alternative splicing and allosteric regulation modulate the chromatin binding of UHRF1.
机构信息
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Biological and Environmental Science and Engineering Division, Laboratory of Chromatin Biochemistry, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia.
出版信息
Nucleic Acids Res. 2020 Aug 20;48(14):7728-7747. doi: 10.1093/nar/gkaa520.
UHRF1 is an important epigenetic regulator associated with apoptosis and tumour development. It is a multidomain protein that integrates readout of different histone modification states and DNA methylation with enzymatic histone ubiquitylation activity. Emerging evidence indicates that the chromatin-binding and enzymatic modules of UHRF1 do not act in isolation but interplay in a coordinated and regulated manner. Here, we compared two splicing variants (V1, V2) of murine UHRF1 (mUHRF1) with human UHRF1 (hUHRF1). We show that insertion of nine amino acids in a linker region connecting the different TTD and PHD histone modification-binding domains causes distinct H3K9me3-binding behaviour of mUHRF1 V1. Structural analysis suggests that in mUHRF1 V1, in contrast to V2 and hUHRF1, the linker is anchored in a surface groove of the TTD domain, resulting in creation of a coupled TTD-PHD module. This establishes multivalent, synergistic H3-tail binding causing distinct cellular localization and enhanced H3K9me3-nucleosome ubiquitylation activity. In contrast to hUHRF1, H3K9me3-binding of the murine proteins is not allosterically regulated by phosphatidylinositol 5-phosphate that interacts with a separate less-conserved polybasic linker region of the protein. Our results highlight the importance of flexible linkers in regulating multidomain chromatin binding proteins and point to divergent evolution of their regulation.
UHRF1 是一种与细胞凋亡和肿瘤发生相关的重要表观遗传调节因子。它是一种多功能蛋白,可整合不同组蛋白修饰状态和 DNA 甲基化的读出,并具有酶促组蛋白泛素化活性。新出现的证据表明,UHRF1 的染色质结合和酶模块不是孤立作用,而是以协调和受调控的方式相互作用。在这里,我们比较了两种鼠源 UHRF1(mUHRF1)和人源 UHRF1(hUHRF1)的剪接变体(V1、V2)。我们表明,在连接不同 TTD 和 PHD 组蛋白修饰结合域的连接区插入九个氨基酸会导致 mUHRF1 V1 对 H3K9me3 的结合行为不同。结构分析表明,与 V2 和 hUHRF1 相比,在 mUHRF1 V1 中,连接子被锚定在 TTD 结构域的表面凹槽中,导致形成耦合的 TTD-PHD 模块。这建立了多价协同的 H3 尾结合,导致不同的细胞定位和增强的 H3K9me3-核小体泛素化活性。与 hUHRF1 不同,鼠源蛋白的 H3K9me3 结合不受与蛋白中另一个不太保守的多碱性连接子区域相互作用的磷脂酰肌醇 5-磷酸的变构调节。我们的结果强调了灵活连接子在调节多结构域染色质结合蛋白中的重要性,并指出了它们调节的趋异进化。