Function of the MYND Domain and C-Terminal Region in Regulating the Subcellular Localization and Catalytic Activity of the SMYD Family Lysine Methyltransferase Set5
Function of the MYND Domain and C-Terminal Region in Regulating the Subcellular Localization and Catalytic Activity of the SMYD Family Lysine Methyltransferase Set5
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DOI：
10.1128/mcb.00341-19
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发表时间：
2020-01-01
影响因子：
5.3
通讯作者：
Green, Erin M.
中科院分区：
文献类型：
--
作者：
Jaiswal, Deepika;Turniansky, Rashi;Green, Erin M.
SMYD 赖氨酸甲基转移酶以组蛋白和非组蛋白甲基化为目标，是肌肉发育的关键调节因子，并参与肿瘤转化。它们的特征是一个分裂的催化 SET 结构域和一个插入的 MYND 锌指结构域，以及一个扩展的 C 端结构域。酿酒酵母含有两种 SMYD 蛋白 SetS 和 Set6，它们与哺乳动物 SMYD 酶共享结构元件。 SetS 是一种组蛋白 H4 赖氨酸 5、8 和 12 甲基转移酶，参与应激反应和基因组稳定性的调节。虽然 SMYD 蛋白在细胞中具有多种作用，但我们对这些酶如何调节的理解还存在许多差距。在这里，我们结合磷酸蛋白质组学对 Set5 进行了突变分析，以确定其酶活性和亚细胞定位的调控机制。我们的结果表明，MYND 结构域促进细胞中 SetS 染色质关联，并且是其抑制亚端粒基因的作用所必需的。磷酸蛋白质组学揭示了 Set5 的广泛磷酸化，并且拟磷突变增强了 Set5 的催化活性，但降低了其与细胞中染色质相互作用的能力。这些研究揭示了 SetS 内调节其定位和活性的多个区域，并强调了理解控制 SMYD 酶不同作用的机制的潜在途径。
SMYD lysine methyltransferases target histones and nonhistone proteins for methylation and are critical regulators of muscle development and implicated in neoplastic transformation. They are characterized by a split catalytic SET domain and an intervening MYND zinc finger domain, as well as an extended C-terminal domain. Saccharomyces cerevisiae contains two SMYD proteins, SetS and Set6, which share structural elements with the mammalian SMYD enzymes. SetS is a histone H4 lysine 5, 8, and 12 methyltransferase, implicated in the regulation of stress responses and genome stability. While the SMYD proteins have diverse roles in cells, there are many gaps in our understanding of how these enzymes are regulated. Here, we performed mutational analysis of Set5, combined with phosphoproteomics, to identify regulatory mechanisms for its enzymatic activity and subcellular localization. Our results indicate that the MYND domain promotes SetS chromatin association in cells and is required for its role in repressing subtelomeric genes. Phosphoproteomics revealed extensive phosphorylation of Set5, and phosphomimetic mutations enhance Set5 catalytic activity but diminish its ability to interact with chromatin in cells. These studies uncover multiple regions within SetS that regulate its localization and activity and highlight potential avenues for understanding mechanisms controlling the diverse roles of SMYD enzymes.