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Gene Review

HNRNPU  -  heterogeneous nuclear ribonucleoprotein U...

Homo sapiens

Synonyms: HNRPU, Heterogeneous nuclear ribonucleoprotein U, SAF-A, SAFA, Scaffold attachment factor A, ...
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Disease relevance of HNRPU

  • Retrovirus integration site Mintb encoding the mouse homolog of hnRNP U [1].
  • When tested in the human immunodeficiency virus type 1 transcription system, hnRNP U inhibits elongation rather than initiation of transcription by Pol II [2].
  • With ascites fluids in isotonic buffer containing antibodies to nucleolar proteins p120 and C23, a maximum number of cells, 86 and 84%, respectively, were loaded following a 20-min incubation [3].
  • Treatment with anti-lyn Abs coimmunoprecipitated, along with lyn product, the beta subunit of GM-CSFR and a phosphoprotein with a molecular mass of 120 kDa (p120) in the lysates of M-07e cells but not in the lysates of human monocyte-derived macrophages (HMDM) or human lymphoid leukemia cells [4].
  • Using polyclonal anti-p120 antibody and anti-120 kDa nuclear ribonucleoprotein monoclonal antibody (mAb), p120 was identified as a nuclear ribonucleoprotein antigenically not related to EBV/C3dR [5].

High impact information on HNRPU

  • The junctional proteins ZO-1 and p120 redistribute in a dotted circle peripheral to the brush border, in the absence of cell-cell contacts [6].
  • By these criteria, the mammalian cells contain both GAP activities and the oocytes have only p120-like GAP activity [7].
  • This protein occupies E3RS in a specific and stoichiometric manner, stabilizes the E3 component, and is likely responsible for its nuclear localization. hnRNP-U binding was abolished by competition with a pIkappaB(alpha) peptide, or by a specific point mutation in the E3RS WD region, indicating an E3-substrate-type interaction [8].
  • Inhibition of HIV-1 gene expression by a fragment of hnRNP U [9].
  • Whereas expression of Ki-67 or p120 on micrometastatic cells was observed only in 11 (15.9%) of 69 cancer patients analyzed, ErbB2+/CK18+ cells were found in 48 (67.6%) of 71 breast cancer patients and 14 (28.0%) of 50 patients with gastrointestinal cancer (P = .0001) [10].

Chemical compound and disease context of HNRPU

  • Furthermore, p120 was tyrosine phosphorylated in avian cells expressing middle T antigen, the transforming protein of polyomavirus, as well as in rodent cells stimulated with either epidermal growth factor (EGF) or platelet-derived growth factor [11].
  • Using the pre-S protein fused to glutathione S-transferase and immobilized on Sepharose beads, we have now identified an additional binding protein with a size of 120 kDa (p120). p120 expression is restricted to the liver, kidney, and pancreas, the three major organs of DHBV replication [12].
  • Conserved serine-rich motifs identified in the repeat units of P120 and P140 were also found in the repeat units of the human granulocytotropic ehrlichiosis agent 130-kDa protein and of the fimbria-associated adhesin protein Fap1 of Streptococcus parasanguis [13].
  • The glycoprotein genes of Ehrlichia chaffeensis (1,644 bp) and Ehrlichia canis (2,064 bp) encode proteins of 548 to 688 amino acids with predicted molecular masses of only 61 and 73 kDa but with electrophoretic mobilities of 120 kDa (P120) and 140 kDa (P140), respectively [13].
  • Tyrosine phosphorylation of p120 in 1321N1 astrocytoma cells was less sensitive to modulation by peroxynitrite [14].

Biological context of HNRPU


Anatomical context of HNRPU


Associations of HNRPU with chemical compounds


Physical interactions of HNRPU


Regulatory relationships of HNRPU

  • In contrast, hnRNP U has no effect when co-expressed with a truncated YAP protein lacking the hnRNP U-binding site [17].
  • The abilities of hnRNP U to inhibit TFIIH-mediated CTD phosphorylation and its Pol II association are necessary for hnRNP U to mediate the repression of Pol II elongation [2].
  • These results suggest that necdin suppresses cell proliferation through its interaction with hnRNP U in the specific subnuclear structure [26].
  • Ecto-protein kinase substrate p120 revealed as the cell-surface-expressed nucleolar phosphoprotein Nopp140: a candidate protein for extracellular Ca2+-sensing [27].

Other interactions of HNRPU

  • Furthermore, hnRNP U and YAP only interact in the nucleus, suggesting that the association between the two proteins is regulated [17].
  • Actin and hnRNP U cooperate for productive transcription by RNA polymerase II [28].
  • The structure revealed a unique four-helix bundle with a topology of an up-down-extended loop-down-up, a part of which the helix-extended loop-helix represented the SAP (SAF-A/B, Acinus, and PIAS) motif [29].
  • Like p53, induction of p120 by anticancer drugs did not require transcription [23].
  • The 120-kDa serine/threonine phosphorylated protein that coprecipitated with PLC gamma 1 resembled the Syk-associated pp120 by several criteria [20].

Analytical, diagnostic and therapeutic context of HNRPU


  1. Retrovirus integration site Mintb encoding the mouse homolog of hnRNP U. Matsui, M., Breau, W.C., Iwasaki, S., Hagiwara, S., Tamai, Y., Mori, C., Bloom, M.L., Jerry, M.B., Eddy, E.M., Taketo, M.M. J. Biochem. (1999) [Pubmed]
  2. hnRNP U inhibits carboxy-terminal domain phosphorylation by TFIIH and represses RNA polymerase II elongation. Kim, M.K., Nikodem, V.M. Mol. Cell. Biol. (1999) [Pubmed]
  3. Optimal loading of scraped HeLa cells with monoclonal antibodies to the proliferation-associated Mr 120,000 nucleolar antigen. Freeman, J.W., Hazlewood, J.E., Auerbach, P., Busch, H. Cancer Res. (1988) [Pubmed]
  4. Association between Lyn protein tyrosine kinase (p53/56lyn) and the beta subunit of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors in a GM-CSF-dependent human megakaryocytic leukemia cell line (M-07e). Li, Y., Shen, B.F., Karanes, C., Sensenbrenner, L., Chen, B. J. Immunol. (1995) [Pubmed]
  5. gp140, the EBV/C3d receptor (CR2) of human B lymphocytes, is involved in cell-free phosphorylation of p120, a nuclear ribonucleoprotein. Delcayre, A.X., Fiandino, A., Barel, M., Frade, R. Eur. J. Immunol. (1987) [Pubmed]
  6. Complete polarization of single intestinal epithelial cells upon activation of LKB1 by STRAD. Baas, A.F., Kuipers, J., van der Wel, N.N., Batlle, E., Koerten, H.K., Peters, P.J., Clevers, H.C. Cell (2004) [Pubmed]
  7. Differential regulation of rasGAP and neurofibromatosis gene product activities. Bollag, G., McCormick, F. Nature (1991) [Pubmed]
  8. Pseudosubstrate regulation of the SCF(beta-TrCP) ubiquitin ligase by hnRNP-U. Davis, M., Hatzubai, A., Andersen, J.S., Ben-Shushan, E., Fisher, G.Z., Yaron, A., Bauskin, A., Mercurio, F., Mann, M., Ben-Neriah, Y. Genes Dev. (2002) [Pubmed]
  9. Inhibition of HIV-1 gene expression by a fragment of hnRNP U. Valente, S.T., Goff, S.P. Mol. Cell (2006) [Pubmed]
  10. Differential expression of proliferation-associated molecules in individual micrometastatic carcinoma cells. Pantel, K., Schlimok, G., Braun, S., Kutter, D., Lindemann, F., Schaller, G., Funke, I., Izbicki, J.R., Riethmüller, G. J. Natl. Cancer Inst. (1993) [Pubmed]
  11. Tyrosine phosphorylation of a 120-kilodalton pp60src substrate upon epidermal growth factor and platelet-derived growth factor receptor stimulation and in polyomavirus middle-T-antigen-transformed cells. Kanner, S.B., Reynolds, A.B., Parsons, J.T. Mol. Cell. Biol. (1991) [Pubmed]
  12. Characterization of a 120-Kilodalton pre-S-binding protein as a candidate duck hepatitis B virus receptor. Li, J.S., Tong, S.P., Wands, J.R. J. Virol. (1996) [Pubmed]
  13. Glycosylation of homologous immunodominant proteins of Ehrlichia chaffeensis and Ehrlichia canis. McBride, J.W., Yu, X.J., Walker, D.H. Infect. Immun. (2000) [Pubmed]
  14. Peroxynitrite modulates tyrosine phosphorylation and phosphoinositide signalling in human neuroblastoma SH-SY5Y cells: attenuated effects in human 1321N1 astrocytoma cells. Li, X., De Sarno, P., Song, L., Beckman, J.S., Jope, R.S. Biochem. J. (1998) [Pubmed]
  15. The glucocorticoid receptor is associated with the RNA-binding nuclear matrix protein hnRNP U. Eggert, M., Michel, J., Schneider, S., Bornfleth, H., Baniahmad, A., Fackelmayer, F.O., Schmidt, S., Renkawitz, R. J. Biol. Chem. (1997) [Pubmed]
  16. Arginine methylation of scaffold attachment factor A by heterogeneous nuclear ribonucleoprotein particle-associated PRMT1. Herrmann, F., Bossert, M., Schwander, A., Akgün, E., Fackelmayer, F.O. J. Biol. Chem. (2004) [Pubmed]
  17. Heterogeneous nuclear ribonuclear protein U associates with YAP and regulates its co-activation of Bax transcription. Howell, M., Borchers, C., Milgram, S.L. J. Biol. Chem. (2004) [Pubmed]
  18. Major cell surface-located protein substrates of an ecto-protein kinase are homologs of known nuclear proteins. Jordan, P., Heid, H., Kinzel, V., Kübler, D. Biochemistry (1994) [Pubmed]
  19. Effects of the heterogeneous nuclear ribonucleoprotein U (hnRNP U/SAF-A) on glucocorticoid-dependent transcription in vivo. Eggert, H., Schulz, M., Fackelmayer, F.O., Renkawitz, R., Eggert, M. J. Steroid Biochem. Mol. Biol. (2001) [Pubmed]
  20. Human spleen tyrosine kinase p72Syk associates with the Src-family kinase p53/56Lyn and a 120-kDa phosphoprotein. Sidorenko, S.P., Law, C.L., Chandran, K.A., Clark, E.A. Proc. Natl. Acad. Sci. U.S.A. (1995) [Pubmed]
  21. Destabilized adhesion in the gastric proliferative zone and c-Src kinase activation mark the development of early diffuse gastric cancer. Humar, B., Fukuzawa, R., Blair, V., Dunbier, A., More, H., Charlton, A., Yang, H.K., Kim, W.H., Reeve, A.E., Martin, I., Guilford, P. Cancer Res. (2007) [Pubmed]
  22. Activation of src family kinases in human pre-B cells by IL-7. Seckinger, P., Fougereau, M. J. Immunol. (1994) [Pubmed]
  23. Like p53, the proliferation-associated protein p120 accumulates in human cancer cells following exposure to anticancer drugs. Blagosklonny, M.V., Iglesias, A., Zhan, Z., Fojo, T. Biochem. Biophys. Res. Commun. (1998) [Pubmed]
  24. Overexpression of human nucleolar proteins in insect cells: characterization of nucleolar protein p120. Ren, Y., Busch, R., Durban, E., Taylor, C., Gustafson, W.C., Valdez, B., Li, Y.P., Smetana, K., Busch, H. Protein Expr. Purif. (1996) [Pubmed]
  25. E1B 55-kilodalton-associated protein: a cellular protein with RNA-binding activity implicated in nucleocytoplasmic transport of adenovirus and cellular mRNAs. Gabler, S., Schütt, H., Groitl, P., Wolf, H., Shenk, T., Dobner, T. J. Virol. (1998) [Pubmed]
  26. Necdin interacts with the ribonucleoprotein hnRNP U in the nuclear matrix. Taniura, H., Yoshikawa, K. J. Cell. Biochem. (2002) [Pubmed]
  27. Ecto-protein kinase substrate p120 revealed as the cell-surface-expressed nucleolar phosphoprotein Nopp140: a candidate protein for extracellular Ca2+-sensing. Kübler, D. Biochem. J. (2001) [Pubmed]
  28. Actin and hnRNP U cooperate for productive transcription by RNA polymerase II. Kukalev, A., Nord, Y., Palmberg, C., Bergman, T., Percipalle, P. Nat. Struct. Mol. Biol. (2005) [Pubmed]
  29. NMR structure of the N-terminal domain of SUMO ligase PIAS1 and its interaction with tumor suppressor p53 and A/T-rich DNA oligomers. Okubo, S., Hara, F., Tsuchida, Y., Shimotakahara, S., Suzuki, S., Hatanaka, H., Yokoyama, S., Tanaka, H., Yasuda, H., Shindo, H. J. Biol. Chem. (2004) [Pubmed]
  30. Scaffold/matrix attachment region elements interact with a p300-scaffold attachment factor A complex and are bound by acetylated nucleosomes. Martens, J.H., Verlaan, M., Kalkhoven, E., Dorsman, J.C., Zantema, A. Mol. Cell. Biol. (2002) [Pubmed]
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