Forms a complex with an importin alpha subunit. Forms a heterodimer with IPO7. Interacts with IPO7, SNUPN, RPL23A and XPO1. The KPNB1/IPO7 heterodimer interacts with H1 histone. Interacts with H2A, H2B, H3 and H4 histones (By similarity). Component of an import snRNP complex composed of KPNB1, SNUPN, SMN1 and ZNF259. Component of a nuclear export receptor complex composed of KPNB1, Ran, SNUPN and XPO1. Binds to HIV-1 Rev and Tat. Interacts with HTLV-1 Rex. Interacts with SRY. Interacts with PRKCI/atypical protein kinase C iota. Interacts with human respiratory syncytial virus (HRSV) protein M. Interacts with KPNA7.