PSMB5 and liver cancer: It is reported that Poly (rC) binding protein 2 (PCBP2) directly interacted with both tribbles homolog 2 (TRIB2) and PSMB5, and TRIB2 plays a critical role by modulating PSMB5 activity in reducing Ub flux, this interaction was found to maintain the viability of the liver cancer cells and promote tumor growth [53].