Multifunctional protein that is involved in the regulation of many processes including cell proliferation, apoptosis, cell cycle progression or transcription (PubMed:18039846, PubMed:20015864). Regulates the proliferation of neuronal stem cells, differentiation of leukemic cells and progression from G1 to S phase of the cell cycle. As negative regulator of caspase-3-dependent apoptosis, may act as an antagonist of ANP32A in regulating tissue homeostasis (PubMed:20015864). Exhibits histone chaperone properties, able to recruit histones to certain promoters, thus regulating the transcription of specific genes (PubMed:18039846, PubMed:20538007). Also plays an essential role in the nucleocytoplasmic transport of specific mRNAs via the uncommon nuclear mRNA export receptor XPO1/CRM1 (PubMed:17178712). Participates in the regulation of adequate adaptive immune responses by acting on mRNA expression and cell proliferation (By similarity). ; (Microbial infection) Plays an essential role in influenza A and B viral genome replication (PubMed:31217244, PubMed:33045004). Also plays a role in foamy virus mRNA export from the nucleus to the cytoplasm (PubMed:21159877).
