Plays a role in the regulation of diverse cellular processes such as ribosome biogenesis, chromatin remodeling or protein chaperoning (PubMed:20073534, PubMed:22362753). Modulates the histone chaperone function and the RNA-binding activity of nucleolar phosphoprotein B23/NPM (PubMed:22362753). Efficiently mediates chromatin remodeling when included in a pentamer containing NPM3 and NPM (PubMed:15596447).