文章：

通过PRMT5依赖性对称二甲基化调控RORα稳定性

Regulation of RORα Stability through PRMT5-Dependent Symmetric Dimethylation

原文发布日期：17 May 2024

DOI: 10.3390/cancers16101914

类型: Article

开放获取: 是

英文摘要：

Retinoic acid receptor-related orphan receptor alpha (RORα), a candidate tumor suppressor, is prevalently downregulated or lost in malignant breast cancer cells. However, the mechanisms of how RORα expression is regulated in breast epithelial cells remain incompletely understood. Protein arginine N-methyltransferase 5 (PRMT5), a type II methyltransferase catalyzing the symmetric methylation of the amino acid arginine in target proteins, was reported to regulate protein stability. To study whether and how PRMT5 regulates RORα, we examined the direct interaction between RORα and PRMT5 by immunoprecipitation and GST pull-down assays. The results showed that PRMT5 directly bound to RORα, and PRMT5 mainly symmetrically dimethylated the DNA-binding domain (DBD) but not the ligand-binding domain (LBD) of RORα. To investigate whether RORα protein stability is regulated by PRMT5, we transfected HEK293FT cells with RORα and PRMT5-expressing or PRMT5-silencing (shPRMT5) vectors and then examined RORα protein stability by a cycloheximide chase assay. The results showed that PRMT5 increased RORα protein stability, while silencing PRMT5 accelerated RORα protein degradation. In PRMT5-silenced mammary epithelial cells, RORα protein expression was decreased, accompanied by an enhanced epithelial–mesenchymal transition morphology and cell invasion and migration abilities. In PRMT5-overexpressed mammary epithelial cells, RORα protein was accumulated, and cell invasion was suppressed. These findings revealed a novel mechanism by which PRMT5 regulates RORα protein stability.

摘要翻译： 

视黄酸受体相关孤儿受体α（RORα）作为一种候选肿瘤抑制因子，在恶性乳腺癌细胞中普遍存在表达下调或缺失现象。然而，关于RORα在乳腺上皮细胞中表达调控的具体机制尚未完全阐明。蛋白精氨酸N-甲基转移酶5（PRMT5）作为II型甲基转移酶，可催化靶蛋白中精氨酸残基的对称二甲基化，已有研究报道其参与蛋白质稳定性调控。为探究PRMT5是否及如何调控RORα，我们通过免疫共沉淀和GST pull-down实验检测了RORα与PRMT5的直接相互作用。结果显示PRMT5可直接结合RORα，并主要在其DNA结合域（DBD）而非配体结合域（LBD）进行对称二甲基化修饰。为验证PRMT5是否调控RORα蛋白稳定性，我们在HEK293FT细胞中转染RORα与PRMT5过表达或PRMT5沉默（shPRMT5）载体，通过放线菌酮追踪实验检测RORα蛋白稳定性。结果表明PRMT5可增强RORα蛋白稳定性，而沉默PRMT5则加速其降解。在PRMT5沉默的乳腺上皮细胞中，RORα蛋白表达降低，同时上皮-间质转化形态特征增强，细胞侵袭和迁移能力提升；而在PRMT5过表达的乳腺上皮细胞中，RORα蛋白积累且细胞侵袭受到抑制。这些发现揭示了PRMT5调控RORα蛋白稳定性的新机制。

原文链接：

Regulation of RORα Stability through PRMT5-Dependent Symmetric Dimethylation