Rat Nucleophosmin,Npm1 ELI

Involved in diverse cellular processes such as ribosome biogenesis, centrosome duplication, protein chaperoning, histone assembly, cell proliferation, and regulation of tumor suppressors p53/TP53 and ARF.

Binds ribosome presumably to drive ribosome nuclear export.

Associated with nucleolar ribonucleoprotein structures and bind single-stranded nucleic acids.

Acts as a chaperonin for the core histones H3, H2B and H4.

Stimulates APEX1 endonuclease activity on apurinic/apyrimidinic (AP) double-stranded DNA but inhibits APEX1 endonuclease activity on AP single-stranded RNA.

May exert a control of APEX1 endonuclease activity within nucleoli devoted to repair AP on rDNA and the removal of oxidized rRNA molecules.

In concert with BRCA2, regulates centrosome duplication.

Regulates centriole duplication: phosphorylation by PLK2 is able to trigger centriole replication.

Negatively regulates the activation of EIF2AK2/PKR and suppresses apoptosis through inhibition of EIF2AK2/PKR autophosphorylation.

Antagonizes the inhibitory effect of ATF5 on cell proliferation and relieves ATF5-induced G2/M blockade.

In complex with MYC enhances the transcription of MYC target genes.

{ECO:0000250|UniProtKB:P06748}.