Methylation of proteins is emerging to be an important regulator of protein function. SET7/9, a protein lysine methyltransferase, catalyses methylation of several proteins involved in diverse biological processes. SET7/9-mediated methylation often regulates the stability, sub-cellular localization and protein-protein interactions of its substrate proteins. Here, we aimed to identify novel biological processes regulated by SET7/9 by identifying new interaction partners. For this we used yeast two-hybrid screening and identified the large subunit ribosomal protein, eL42 as a potential interactor of SET7/9. We confirmed the SET7/9-eL42 interaction by co-immunoprecipitation and GST pulldown studies. The N-terminal MORN domain of SET7/9 is essential for its interaction with eL42. Importantly, we identified that SET7/9 methylates eL42 at three different lysines - Lys53, Lys80 and Lys100 through site-directed mutagenesis. By puromycin incorporation assay, we find that SET7/9-mediated methylation of eL42 affects global translation. This study identifies a new role of the functionally versatile SET7/9 lysine methyltransferase in the regulation of global protein synthesis.

中文翻译：

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SET7 / 9相互作用并甲基化核糖体蛋白eL42，并调节蛋白合成。

蛋白质的甲基化正在成为蛋白质功能的重要调节剂。SET7 / 9是一种蛋白质赖氨酸甲基转移酶，可催化涉及多种生物学过程的几种蛋白质的甲基化。SET7 / 9介导的甲基化通常调节其底物蛋白的稳定性，亚细胞定位和蛋白-蛋白相互作用。在这里，我们旨在通过识别新的相互作用伙伴来识别由SET7 / 9调控的新型生物过程。为此，我们使用了酵母双杂交筛选并确定了大的亚基核糖体蛋白eL42作为SET7 / 9的潜在相互作用物。我们通过免疫共沉淀和GST下拉研究证实了SET7 / 9-eL42的相互作用。SET7 / 9的N端MORN域对于与eL42相互作用至关重要。重要的，我们确定SET7 / 9通过定点诱变在三种不同的赖氨酸-Lys53，Lys80和Lys100处使eL42甲基化。通过嘌呤霉素掺入试验，我们发现SET7 / 9介导的eL42甲基化影响整体翻译。这项研究确定了功能多样的SET7 / 9赖氨酸甲基转移酶在调节全球蛋白质合成中的新作用。