Arginine methylation of translocated in liposarcoma (TLS) inhibits its binding to long noncoding RNA, abrogating TLS-mediated repression of CBP/p300 activity
Arginine methylation of translocated in liposarcoma (TLS) inhibits its binding to long noncoding RNA, abrogating TLS-mediated repression of CBP/p300 activity
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DOI：
10.1074/jbc.ra117.000598
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发表时间：
2018-07-13
影响因子：
4.8
通讯作者：
Kurokawa, Riki
中科院分区：
文献类型：
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作者：
Cui, Wei;Yoneda, Ryoma;Kurokawa, Riki
脂肪肉瘤中易位 (TLS) 是一种 RNA 结合蛋白，也是 DNA 损伤的转录调节传感器。 TLS 结合启动子相关非编码 RNA (pncRNA)，并抑制细胞周期蛋白 D1 (CCND1) 基因上 CREB 结合蛋白 (CBP)/E1A 结合蛋白 P300 (p300) 的组蛋白乙酰转移酶 (HAT) 活性。尽管已知 TLS 的翻译后修饰（例如精氨酸甲基化）可调节应激颗粒中 TLS 的核质穿梭和组装，但其与 RNA 的相互作用仍知之甚少。在此，利用各种生化测定，我们证实了早期的观察结果，即 TLS 在体外被蛋白精氨酸甲基转移酶 1 (PRMT1) 甲基化。 TLS 的精氨酸甲基化破坏了与 pncRNA 的结合，并且还阻止了 TLS 与 CBP/p300 的结合和抑制。该结果表明 TLS 的精氨酸甲基化消除了与 pncRNA 的结合以及 TLS 介导的 CBP/p300 HAT 活性抑制。我们还报告称，TLS 的 Arg-Gly-Gly 结构域内的精氨酸残基 Arg-476 是与 pncRNA 结合的主要决定因素。 TLS 的 Arg-476 甲基化或突变显着降低了 pncRNA 结合，从而阻止了 pncRNA 诱导的 TLS 变构改变，而这是 TLS 与 CBP/p300 相互作用所必需的。此外，与 WT TLS 不同，R476A TLS 突变体在荧光素酶报告基因检测中不会抑制 CCND1 启动子活性。综上所述，我们提出以下假设：TLS 的精氨酸甲基化调节 TLS-核酸和 TLS-蛋白质相互作用，从而参与转录调节。
Translocated in liposarcoma (TLS) is an RNA-binding protein and a transcription-regulatory sensor of DNA damage. TLS binds promoter-associated noncoding RNA (pncRNA) and inhibits histone acetyltransferase (HAT) activity of CREB-binding protein (CBP)/E1A-binding protein P300 (p300) on the cyclin D1 (CCND1) gene. Although post-translational modifications of TLS, such as arginine methylation, are known to regulate TLS's nucleocytoplasmic shuttling and assembly in stress granules, its interactions with RNAs remain poorly characterized. Herein, using various biochemical assays, we confirmed the earlier observations that TLS is methylated by protein arginine methyltransferase 1 (PRMT1) in vitro. The arginine methylation of TLS disrupted binding to pncRNA and also prevented binding of TLS to and inhibition of CBP/p300. This result indicated that arginine methylation of TLS abrogates both binding to pncRNA and TLS-mediated inhibition of CBP/p300 HAT activities. We also report that an arginine residue within the Arg-Gly-Gly domain of TLS, Arg-476, serves as the major determinant for binding to pncRNA. Either methylation or mutation of Arg-476 of TLS significantly decreased pncRNA binding and thereby prevented a pncRNA-induced allosteric alteration in TLS that is required for its interaction with CBP/p300. Moreover, unlike WT TLS, an R476A TLS mutant did not inhibit CCND1 promoter activity in luciferase reporter assays. Taken together, we propose the hypothesis that arginine methylation of TLS regulates both TLS-nucleic acid and TLS-protein interactions and thereby participates in transcriptional regulation.