肝细胞癌 (HCC) 是最常见和致命的肿瘤之一；然而，其致病机制在很大程度上仍不清楚。需要深入研究揭示RNA结合蛋白RALY在HCC中的表达调控机制和功能。在这里，我们将 RALY 确定为一种高表达的致癌因子，在体外和体内都会影响 HCC 细胞的增殖。 RALY Ser176 位点的 O-GlcNAc 酰化通过保护 RALY 免受 TRIM27 介导的泛素化来增强其稳定性，从而维持 RALY 蛋白的超表达。从机制上讲，RNA 免疫沉淀显示，RALY 与 USP22 信使 RNA 相互作用，增加其细胞质定位和蛋白质表达，从而促进 HCC 细胞的增殖。此外，我们开发了一种基于肽蛋白水解靶向嵌合体的新型 RALY 蛋白降解剂，名为 RALY-PROTAC，我们通过将 RALY 靶向肽与 E3 泛素连接酶招募配体泊马度胺连接来化学合成。总之，我们的研究结果证明了 O-GlcNAcylation/RALY/USP22 mRNA 轴加剧 HCC 细胞增殖的新机制。 RALY-PROTAC 作为 RALY 蛋白的降解剂，具有作为 RALY 过表达 HCC 治疗药物的潜力。© 作者。

Hepatocellular carcinoma (HCC) is one of the most prevalent and deadly tumors; however, its pathogenic mechanism remains largely elusive. In-depth researches are needed to reveal the expression regulatory mechanisms and functions of the RNA-binding protein RALY in HCC. Here, we identify RALY as a highly expressed oncogenic factor that affects HCC cells proliferation both in vitro and in vivo. O-GlcNAcylation of RALY at Ser176 enhances its stability by protecting RALY from TRIM27-mediated ubiquitination, thus maintaining hyper-expression of the RALY protein. Mechanistically, RALY interacts with USP22 messenger RNA, as revealed by RNA immunoprecipitation, to increase their cytoplasmic localization and protein expression, thereby promoting the proliferation of HCC cells. Furthermore, we develop a novel RALY protein degrader based on peptide proteolysis-targeting chimeras, named RALY-PROTAC, which we chemically synthesize by linking a RALY-targeting peptide with the E3 ubiquitin ligase recruitment ligand pomalidomide. In conclusion, our findings demonstrate a novel mechanism by which O-GlcNAcylation/RALY/USP22 mRNA axis aggravates HCC cells proliferation. RALY-PROTACs as degraders of the RALY protein exhibit potential as therapeutic drugs for RALY-overexpressing HCC.© The author(s).