NPM1

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Identifiers
Aliases
External IDs	GeneCards: [1]
Orthologs
Species	Human	Mouse
Entrez	n/a	n/a
Ensembl	n/a	n/a
UniProt	n/a	n/a
RefSeq (mRNA)	n/a	n/a
RefSeq (protein)	n/a	n/a
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Wikidata
View/Edit Human

Nucleophosmin (NPM), also known as nucleolar phosphoprotein B23 or numatrin, is a protein that in humans is encoded by the NPM1 gene.

Function

NPM1 is associated with nucleolar ribonucleoprotein structures and binds single-stranded and double-stranded nucleic acids, but it binds preferentially G-quadruplex forming nucleic acids. It is involved in the biogenesis of ribosomes and may assist small basic proteins in their transport to the nucleolus. Its regulation through SUMOylation (by SENP3 and SENP5) is another facet of the proteins's regulation and cellular functions.

It is located in the nucleolus, but it can be translocated to the nucleoplasm in case of serum starvation or treatment with anticancer drugs. The protein is phosphorylated.

Nucleophosmin has multiple functions:

1. Histone chaperones
2. Ribosome biogenesis and transport
3. Genomic stability and DNA repair
4. Endoribonuclease activity
5. Centrosome duplication during cell cycle
6. Regulation of ARF-p53 tumor suppressor pathway
7. RNA helix destabilizing activity
8. Inhibition of caspase-activated DNase
9. Prevents apoptosis when located in nucleolus

Clinical significance

NPM1 gene is up-regulated, mutated and chromosomally translocated in many tumor types. Chromosomal aberrations involving NPM1 were found in patients with non-Hodgkin lymphoma, acute promyelocytic leukemia, myelodysplastic syndrome, and acute myelogenous leukemia. Heterozygous mice for NPM1 are vulnerable to tumor development. In solid tumors NPM1 is frequently found overexpressed, and it is thought that NPM1 could promote tumor growth by inactivation of the tumor suppressor p53/ARF pathway; on the contrary, when expressed at low levels, NPM1 could suppress tumor growth by the inhibition of centrosome duplication.

Of high importance is NPM involvement in acute myelogenous leukemia, where a mutated protein lacking a folded C-terminal domain (NPM1c+) has been found in the cytoplasm in patients. This aberrant localization has been linked to the development of the disease. Strategies against this subtype of acute myelogenous leukemia include the refolding of the C-terminal domain using pharmalogical chaperones and the displacement of the protein from nucleolus to nucleoplasm, which has been linked to apoptotic mechanisms.

Interactions

NPM1 has been shown to interact with

• AKT1,
• BARD1,
• BRCA1, and
• nucleolin.

Nucleophosmin has multiple binding partners:

1. rRNA
2. HIV Rev and Rex peptide
3. p53 tumor suppressor
4. ARF tumor suppressor
5. MDM2 (mouse double minute 2, ubiquitin ligase)
6. Ribosome protein S9
7. Phosphatidylinositol 3,4,5-triphosphate (PIP3)
8. Exportin-1 (CRM1, chromosome region maintenance)
9. Nucleolin/C23
10. Transcription target of myc oncogene

Further reading

• Yun C, Wang Y, Mukhopadhyay D, et al. (2008). "Nucleolar protein B23/nucleophosmin regulates the vertebrate SUMO pathway through SENP3 and SENP5 proteases". J. Cell Biol. 183 (4): 589–95. doi:10.1083/jcb.200807185. PMC 2582899. PMID 19015314.
• Haindl M, Harasim T, Eick D, et al. (2008). "The nucleolar SUMO-specific protease SENP3 reverses SUMO modification of nucleophosmin and is required for rRNA processing". EMBO Reports. 9 (3): 273–279. doi:10.1038/embor.2008.3. PMC 2267381. PMID 18259216.
• Li L, Li HS, Pauza CD, et al. (2006). "Roles of HIV-1 auxiliary proteins in viral pathogenesis and host-pathogen interactions". Cell Res. 15 (11–12): 923–34. doi:10.1038/sj.cr.7290370. PMID 16354571.
• Gjerset RA (2007). "DNA damage, p14ARF, nucleophosmin (NPM/B23), and cancer". J. Mol. Histol. 37 (5–7): 239–51. doi:10.1007/s10735-006-9040-y. PMID 16855788.
• Chen W, Rassidakis GZ, Medeiros LJ (2006). "Nucleophosmin gene mutations in acute myeloid leukemia". Arch. Pathol. Lab. Med. 130 (11): 1687–92. doi:10.1043/1543-2165(2006)130[1687:NGMIAM]2.0.CO;2. PMID 17076533.
• Falini B, Nicoletti I, Bolli N, et al. (2007). "Translocations and mutations involving the nucleophosmin (NPM1) gene in lymphomas and leukemias". Haematologica. 92 (4): 519–32. doi:10.3324/haematol.11007. PMID 17488663.
• Fankhauser C, Izaurralde E, Adachi Y, et al. (1991). "Specific complex of human immunodeficiency virus type 1 rev and nucleolar B23 proteins: dissociation by the Rev response element". Mol. Cell. Biol. 11 (5): 2567–75. PMC 360026. PMID 2017166.
• Venkatesh LK, Mohammed S, Chinnadurai G (1990). "Functional domains of the HIV-1 rev gene required for trans-regulation and subcellular localization". Virology. 176 (1): 39–47. doi:10.1016/0042-6822(90)90228-J. PMID 2109912.
• Cochrane AW, Perkins A, Rosen CA (1990). "Identification of sequences important in the nucleolar localization of human immunodeficiency virus Rev: relevance of nucleolar localization to function". J. Virol. 64 (2): 881–5. PMC 249184. PMID 2404140.
• Chan PK, Chan WY, Yung BY, et al. (1986). "Amino acid sequence of a specific antigenic peptide of protein B23". J. Biol. Chem. 261 (30): 14335–41. PMID 2429957.
• Zhang XX, Thomis DC, Samuel CE (1989). "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. 164 (1): 176–84. doi:10.1016/0006-291X(89)91699-9. PMID 2478125.
• Hale TK, Mansfield BC (1990). "Nucleotide sequence of a cDNA clone representing a third allele of human protein B23". Nucleic Acids Res. 17 (23): 10112. PMC 335249. PMID 2602120.
• Chan WY, Liu QR, Borjigin J, et al. (1989). "Characterization of the cDNA encoding human nucleophosmin and studies of its role in normal and abnormal growth". Biochemistry. 28 (3): 1033–9. doi:10.1021/bi00429a017. PMID 2713355.
• Li XZ, McNeilage LJ, Whittingham S (1989). "The nucleotide sequence of a human cDNA encoding the highly conserved nucleolar phosphoprotein B23". Biochem. Biophys. Res. Commun. 163 (1): 72–8. doi:10.1016/0006-291X(89)92100-1. PMID 2775293.
• Chan PK, Aldrich M, Cook RG, Busch H (1986). "Amino acid sequence of protein B23 phosphorylation site". J. Biol. Chem. 261 (4): 1868–72. PMID 3944116.
• Bocker T, Bittinger A, Wieland W, et al. (1995). "In vitro and ex vivo expression of nucleolar proteins B23 and p120 in benign and malignant epithelial lesions of the prostate". Mod. Pathol. 8 (3): 226–31. PMID 7542384.
• Dundr M, Leno GH, Hammarskjöld ML, et al. (1995). "The roles of nucleolar structure and function in the subcellular location of the HIV-1 Rev protein". J. Cell Sci. 108 (8): 2811–23. PMID 7593322.
• Miyazaki Y, Takamatsu T, Nosaka T, et al. (1995). "The cytotoxicity of human immunodeficiency virus type 1 Rev: implications for its interaction with the nucleolar protein B23". Exp. Cell Res. 219 (1): 93–101. doi:10.1006/excr.1995.1209. PMID 7628555.
• Szebeni A, Herrera JE, Olson MO (1995). "Interaction of nucleolar protein B23 with peptides related to nuclear localization signals". Biochemistry. 34 (25): 8037–42. doi:10.1021/bi00025a009. PMID 7794916.
• Kato S, Sekine S, Oh SW, et al. (1995). "Construction of a human full-length cDNA bank". Gene. 150 (2): 243–50. doi:10.1016/0378-1119(94)90433-2. PMID 7821789.
• Marasco WA, Szilvay AM, Kalland KH, et al. (1995). "Spatial association of HIV-1 tat protein and the nucleolar transport protein B23 in stably transfected Jurkat T-cells". Arch. Virol. 139 (1–2): 133–54. doi:10.1007/BF01309460. PMID 7826206.
• Valdez BC, Perlaky L, Henning D, et al. (1994). "Identification of the nuclear and nucleolar localization signals of the protein p120. Interaction with translocation protein B23". J. Biol. Chem. 269 (38): 23776–83. PMID 8089149.