Division of Hematology/Oncology, University of Florida Health Cancer Center, Gainesville, Florida 32608; Department of Chemistry and the Department of Molecular Biosciences, and the Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208.
Department of Chemistry and the Department of Molecular Biosciences, and the Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208.
J Biol Chem. 2019 Aug 16;294(33):12459-12471. doi: 10.1074/jbc.RA118.006159. Epub 2019 Jun 27.
NSD2 is a histone methyltransferase that specifically dimethylates histone H3 lysine 36 (H3K36me2), a modification associated with gene activation. Dramatic overexpression of NSD2 in t(4;14) multiple myeloma (MM) and an activating mutation of NSD2 discovered in acute lymphoblastic leukemia are significantly associated with altered gene activation, transcription, and DNA damage repair. The partner proteins through which NSD2 may influence critical cellular processes remain poorly defined. In this study, we utilized proximity-based labeling (BioID) combined with label-free quantitative MS to identify high confidence NSD2 interacting partners in MM cells. The top 24 proteins identified were involved in maintaining chromatin structure, transcriptional regulation, RNA pre-spliceosome assembly, and DNA damage. Among these, an important DNA damage regulator, poly(ADP-ribose) polymerase 1 (PARP1), was discovered. PARP1 and NSD2 have been found to be recruited to DNA double strand breaks upon damage and H3K36me2 marks are enriched at damage sites. We demonstrate that PARP1 regulates NSD2 via PARylation upon oxidative stress. assays suggest the PARylation significantly reduces NSD2 histone methyltransferase activity. Furthermore, PARylation of NSD2 inhibits its ability to bind to nucleosomes and further get recruited at NSD2-regulated genes, suggesting PARP1 regulates NSD2 localization and H3K36me2 balance. This work provides clear evidence of cross-talk between PARylation and histone methylation and offers new directions to characterize NSD2 function in DNA damage response, transcriptional regulation, and other pathways.
NSD2 是一种组蛋白甲基转移酶，特异性地将组蛋白 H3 赖氨酸 36（H3K36me2）二甲基化，这种修饰与基因激活有关。在 t（4；14）多发性骨髓瘤（MM）中，NSD2 的过度表达和急性淋巴细胞白血病中发现的 NSD2 的激活突变与基因激活、转录和 DNA 损伤修复的改变显著相关。NSD2 可能影响关键细胞过程的伴侣蛋白仍未得到很好的定义。在这项研究中，我们利用基于邻近标记（BioID）结合无标记定量 MS 技术，鉴定了 MM 细胞中高可信度的 NSD2 相互作用伙伴。鉴定出的前 24 种蛋白质参与维持染色质结构、转录调控、RNA 前剪接体组装和 DNA 损伤修复。在这些蛋白质中，发现了一种重要的 DNA 损伤调节剂，多聚（ADP-核糖）聚合酶 1（PARP1）。已经发现 PARP1 和 NSD2 在损伤时被招募到 DNA 双链断裂处，并且 H3K36me2 标记在损伤部位富集。我们证明 PARP1 通过 PAR 化在氧化应激时调节 NSD2。PAR 化显著降低 NSD2 组蛋白甲基转移酶活性。此外，PAR 化的 NSD2 抑制其与核小体结合的能力，并进一步招募到 NSD2 调节的基因，表明 PARP1 调节 NSD2 的定位和 H3K36me2 平衡。这项工作为 PAR 化和组蛋白甲基化之间的交叉对话提供了明确的证据，并为 NSD2 在 DNA 损伤反应、转录调控和其他途径中的功能提供了新的研究方向。
