Biology:HNRPU

Generic protein structure example

Heterogeneous nuclear ribonucleoprotein U is a protein that in humans is encoded by the HNRNPU gene.

Function

This gene belongs to the subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins (hnRNPs). The hnRNPs are RNA binding proteins that form complexes with heterogeneous nuclear RNA (hnRNA). These proteins are associated with pre-mRNAs in the nucleus and appear to influence pre-mRNA processing and other aspects of mRNA metabolism and transport. While all of the hnRNPs are present in the nucleus, some seem to shuttle between the nucleus and the cytoplasm. The hnRNP proteins have distinct nucleic acid binding properties. The protein encoded by this gene contains a RNA binding domain and scaffold-associated region (SAR)-specific bipartite DNA-binding domain. This protein is also thought to be involved in the packaging of hnRNA into large ribonucleoprotein complexes. During apoptosis, this protein is cleaved in a caspase-dependent way. Cleavage occurs at the SALD site, resulting in a loss of DNA-binding activity and a concomitant detachment of this protein from nuclear structural sites. But this cleavage does not affect the function of the encoded protein in RNA metabolism. At least two alternatively spliced transcript variants have been identified for this gene.

Interactions

HNRPU has been shown to interact with:

• EP300,
• GTF2F1,
• Glucocorticoid receptor, and
• NDN.

Further reading

• "Primary structure and binding activity of the hnRNP U protein: binding RNA through RGG box.". EMBO J. 11 (7): 2655–64. 1992. doi:10.1002/j.1460-2075.1992.tb05331.x. PMID 1628625. 
• "Binding sites of the Epstein-Barr virus and C3d receptor (CR2, CD21) for its three intracellular ligands, the p53 anti-oncoprotein, the p68 calcium binding protein and the nuclear p120 ribonucleoprotein.". Mol. Immunol. 32 (6): 389–97. 1995. doi:10.1016/0161-5890(95)00005-Y. PMID 7753047. 
• "Human spleen tyrosine kinase p72Syk associates with the Src-family kinase p53/56Lyn and a 120-kDa phosphoprotein.". Proc. Natl. Acad. Sci. U.S.A. 92 (2): 359–63. 1995. doi:10.1073/pnas.92.2.359. PMID 7831290. Bibcode: 1995PNAS...92..359S. 
• "Major cell surface-located protein substrates of an ecto-protein kinase are homologs of known nuclear proteins.". Biochemistry 33 (49): 14696–706. 1995. doi:10.1021/bi00253a007. PMID 7993898. 
• "A novel nuclear structure containing the survival of motor neurons protein.". EMBO J. 15 (14): 3555–65. 1996. doi:10.1002/j.1460-2075.1996.tb00725.x. PMID 8670859. 
• "A novel membrane glycoprotein, SHPS-1, that binds the SH2-domain-containing protein tyrosine phosphatase SHP-2 in response to mitogens and cell adhesion.". Mol. Cell. Biol. 16 (12): 6887–99. 1997. doi:10.1128/MCB.16.12.6887. PMID 8943344. 
• "Thymocyte activation induces the association of phosphatidylinositol 3-kinase and pp120 with CD5.". Eur. J. Immunol. 27 (3): 679–86. 1997. doi:10.1002/eji.1830270316. PMID 9079809. 
• "The class III POU factor Brn-4 interacts with other class III POU factors and the heterogeneous nuclear ribonucleoprotein U.". Brain Res. Mol. Brain Res. 45 (1): 99–107. 1997. doi:10.1016/S0169-328X(96)00238-0. PMID 9105675. https://zenodo.org/record/1259927. 
• "The glucocorticoid receptor is associated with the RNA-binding nuclear matrix protein hnRNP U.". J. Biol. Chem. 272 (45): 28471–8. 1997. doi:10.1074/jbc.272.45.28471. PMID 9353307. 
• "The novel SAR-binding domain of scaffold attachment factor A (SAF-A) is a target in apoptotic nuclear breakdown.". EMBO J. 16 (24): 7361–71. 1998. doi:10.1093/emboj/16.24.7361. PMID 9405365. 
• "Polypyrimidine tract-binding protein interacts with HnRNP L.". FEBS Lett. 425 (3): 401–6. 1998. doi:10.1016/S0014-5793(98)00269-5. PMID 9563502. 
• "Retrovirus integration site Mintb encoding the mouse homolog of hnRNP U.". J. Biochem. 125 (6): 1104–14. 1999. doi:10.1093/oxfordjournals.jbchem.a022392. PMID 10348913. 
• "hnRNP U inhibits carboxy-terminal domain phosphorylation by TFIIH and represses RNA polymerase II elongation.". Mol. Cell. Biol. 19 (10): 6833–44. 2000. doi:10.1128/MCB.19.10.6833. PMID 10490622. 
• "Apoptotic cleavage of scaffold attachment factor A (SAF-A) by caspase-3 occurs at a noncanonical cleavage site.". J. Biol. Chem. 275 (7): 5031–6. 2000. doi:10.1074/jbc.275.7.5031. PMID 10671544. 
• "Proteomic analysis of NMDA receptor-adhesion protein signaling complexes.". Nat. Neurosci. 3 (7): 661–9. 2000. doi:10.1038/76615. PMID 10862698. 
• "Necdin interacts with the ribonucleoprotein hnRNP U in the nuclear matrix.". J. Cell. Biochem. 84 (3): 545–55. 2002. doi:10.1002/jcb.10047. PMID 11813259. 
• "PABP1 identified as an arginine methyltransferase substrate using high-density protein arrays.". EMBO Rep. 3 (3): 268–73. 2002. doi:10.1093/embo-reports/kvf052. PMID 11850402. 
• "Pseudosubstrate regulation of the SCF(beta-TrCP) ubiquitin ligase by hnRNP-U.". Genes Dev. 16 (4): 439–51. 2002. doi:10.1101/gad.218702. PMID 11850407.