Recombinant Human Nucleophosmin (NPM1)

Function

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 (PubMed:22528486). In complex with MYC enhances the transcription of MYC target genes (PubMed:25956029). May act as chaperonin or cotransporter in the nucleolar localization of transcription termination factor TTF1 (By similarity)

Subcellular Location

Nucleus, nucleolus; Nucleus, nucleoplasm; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome

Disease Association

[A chromosomal aberration involving NPM1 is found in a form of non-Hodgkin lymphoma. Translocation t(2;5)(p23;q35) with ALK. The resulting chimeric NPM1-ALK protein homodimerize and the kinase becomes constitutively activated] | [A chromosomal aberration involving NPM1 is found in a form of acute promyelocytic leukemia. Translocation t(5;17)(q32;q11) with RARA] | [A chromosomal aberration involving NPM1 is a cause of myelodysplastic syndrome (MDS). Translocation t(3;5)(q25.1;q34) with MLF1] | [Defects in NPM1 are associated with acute myelogenous leukemia (AML). Mutations in exon 12 affecting the C-terminus of the protein are associated with an aberrant cytoplasmic location]

Subunit

(Microbial infection) Interacts with HTLV1 Rex protein (via N-terminal nuclear localization signal)

• Chan W.-Y. et al. Characterization of the cDNA encoding human nucleophosmin and studies of its role in normal and abnormal growth. — Biochemistry (1989)
• Li X. et al. The nucleotide sequence of a human cDNA encoding the highly conserved nucleolar phosphoprotein B23. — Biochem. Biophys. Res. Commun. (1989)
• Zhang X.T. et al. Isolation and characterization of a molecular cDNA clone of a human mRNA from interferon-treated cells encoding nucleolar protein B23, numatrin. — Biochem. Biophys. Res. Commun. (1989)
• Chan P.-K. et al. Isolation and characterization of the human nucleophosmin/B23 (NPM) gene: identification of the YY1 binding site at the 5' enhancer region. — Nucleic Acids Res. (1997)
• Okuwaki M. et al. Human homologue of Rat B23.2. (APR-)
• Falini B. et al. Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype. — N. Engl. J. Med. (2005)
• Bolli N. et al. Cytoplasmic nucleophosmin in myeloid sarcoma occurring 20 years after diagnosis of acute myeloid leukaemia. — Lancet Oncol. (2006)
• Lu L. et al. Cloning of a new transcript of nucleophosmin in testis. (JUL-)