TRIM41 stabilizes RBPJ through K63 linked ubiquitination and promotes stemness of hepatocellular carcinoma cells.

Persistent activation of the Notch signaling pathway is closely associated with the maintenance of cancer stem cells (CSCs) and the progression of hepatocellular carcinoma (HCC). Recombination signal binding protein for immunoglobulin kappa J region (RBPJ), a key transcription factor that mediates downstream target gene transcription in the Notch pathway, has not been fully characterized with respect to its role in promoting CSC traits in HCC. In this study, we found that RBPJ is markedly upregulated in HCC and is associated with selected clinicopathologic features. RBPJ also promoted stem-like phenotypes in HCC cells. Mechanistically, TRIM41 interacts with RBPJ and mediates K63-linked polyubiquitination of RBPJ at Lys135, thereby stabilizing RBPJ and enhancing RBPJ-mediated transcriptional activation of the stemness-related genes SOX2 and CD44. Consequently, the TRIM41-RBPJ axis sustains CSC-like properties in HCC cells. Our findings identify a previously unrecognized post-translational mechanism by which TRIM41-mediated stabilization of RBPJ promotes stem-like properties. These findings expand our understanding of the post-translational regulation of RBPJ in HCC and highlight the TRIM41-RBPJ axis as a potential molecular target warranting further investigation.