PHB2 and breast carcinoma: More importantly, we also demonstrated that each PHB2-KPNA complex had no effect when only one of the three KPNAs (KPNA1, KPNA5, or KPNA6) was knocked down (Fig 4C), suggesting that the E2-dependent nuclear translocation of endogenous PHB2 is required for its binding to multiple KPNAs (KPNA1, KPNA5, and KPNA6) in breast cancer cells.