UBR5(Ubiquitin Protein Ligase E3 Component N-Recognin 5),也称为N-识别蛋白5,是一种E3泛素连接酶,在细胞生物学中发挥着关键作用。它通过泛素化过程参与蛋白质降解和信号传导途径的调节。UBR5结构上具有一个多腺苷酸结合(PABC)结构域,该结构域能够与RNA结合,从而影响基因表达。
UBR5在多种癌症中表达异常,包括三阴性乳腺癌(TNBC)、卵巢癌和结直肠癌。在TNBC中,UBR5通过增强IFN-γ诱导的PDL1转录,促进肿瘤免疫逃逸[1]。在卵巢癌中,肿瘤来源的UBR5通过诱导免疫抑制性巨噬细胞的募集和活化,促进肿瘤生长和转移[2]。在结直肠癌中,UBR5通过抑制铁死亡,介导化疗耐药性[6]。
除了在癌症中的作用,UBR5还参与抗病毒免疫反应的调节。UBR5通过去泛素化TRIM28,解除其对RIG-I样受体(RLRs)转录的抑制,从而促进抗病毒免疫反应[3]。
UBR5的表达水平与多种肿瘤的发生、发展和预后相关。在肝细胞癌中,UBR5表达升高与肿瘤分级、淋巴结转移和不良预后相关[4]。在三阴性乳腺癌中,UBR5通过泛素化依赖性降解SF3A2,调节MKRN1的剪接,进而影响TNBC的进展和顺铂耐药性[5]。
综上所述,UBR5是一种重要的E3泛素连接酶,参与蛋白质降解、信号传导途径和基因表达的调节。UBR5在多种癌症中表达异常,影响肿瘤的发生、发展和预后。UBR5的研究有助于深入理解泛素化在细胞生物学和疾病发生中的作用,为癌症的治疗提供新的思路和策略。
参考文献:
1. Wu, Bingbing, Song, Mei, Dong, Qun, Ma, Xiaojing, Wei, Fang. 2022. UBR5 promotes tumor immune evasion through enhancing IFN-γ-induced PDL1 transcription in triple negative breast cancer. In Theranostics, 12, 5086-5102. doi:10.7150/thno.74989. https://pubmed.ncbi.nlm.nih.gov/35836797/
2. Song, Mei, Yeku, Oladapo O, Rafiq, Sarwish, Brentjens, Renier J, Ma, Xiaojing. 2020. Tumor derived UBR5 promotes ovarian cancer growth and metastasis through inducing immunosuppressive macrophages. In Nature communications, 11, 6298. doi:10.1038/s41467-020-20140-0. https://pubmed.ncbi.nlm.nih.gov/33293516/
3. Yang, Duomeng, Geng, Tingting, Harrison, Andrew G, Wang, Yanlin, Wang, Penghua. 2024. UBR5 promotes antiviral immunity by disengaging the transcriptional brake on RIG-I like receptors. In Nature communications, 15, 780. doi:10.1038/s41467-024-45141-1. https://pubmed.ncbi.nlm.nih.gov/38278841/
4. Huo, Qi, Hu, Junjie, Hou, Binfen, Du, Yulin, Li, Yao. 2022. Clinicopathological Features and Prognostic Evaluation of UBR5 in Liver Cancer Patients. In Pathology oncology research : POR, 28, 1610396. doi:10.3389/pore.2022.1610396. https://pubmed.ncbi.nlm.nih.gov/36388433/
5. Deng, Ling, Liao, Li, Zhang, Yin-Ling, Shao, Zhi-Ming, Li, Da-Qiang. 2024. SF3A2 promotes progression and cisplatin resistance in triple-negative breast cancer via alternative splicing of MKRN1. In Science advances, 10, eadj4009. doi:10.1126/sciadv.adj4009. https://pubmed.ncbi.nlm.nih.gov/38569025/
6. Song, Mei, Huang, Shuting, Wu, Xiaoxue, Ma, Xiaojing, He, Weiling. 2024. UBR5 mediates colorectal cancer chemoresistance by attenuating ferroptosis via Lys 11 ubiquitin-dependent stabilization of Smad3-SLC7A11 signaling. In Redox biology, 76, 103349. doi:10.1016/j.redox.2024.103349. https://pubmed.ncbi.nlm.nih.gov/39260061/