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. 1996 Aug;70(8):5582–5591. doi: 10.1128/jvi.70.8.5582-5591.1996

Proteasome complex as a potential cellular target of hepatitis B virus X protein.

J Huang 1, J Kwong 1, E C Sun 1, T J Liang 1
PMCID: PMC190518  PMID: 8764072

Abstract

Although the biological importance of hepatitis B virus X protein (HBX) in the life cycle of hepatitis B virus has been well established, the cellular and molecular basis of its function remains largely undefined. Despite the association of multiple activities with HBX, none of them appear to provide a unifying hypothesis regarding the true biological function of HBX. Identification and characterization of cellular targets of HBX remain an essential goal in the elucidation of the molecular mechanisms of HBX. Using the Saccharomyces cerevisiae two-hybrid system, we have identified and characterized a novel subunit of the proteasome complex (XAPC7) that interacts specifically with HBX. We also showed that HBX binds specifically to XAPC7 in vitro. Mutagenesis studies have defined the domains of interaction to be critical for the function of HBX. Furthermore, overexpression of XAPC7 appeared to activate transcription by itself and antisense expression of XAPC7 was able to block transactivation by HBX. Therefore, the proteasome complex is possibly a functional target of HBX in cells.

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Selected References

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  1. Andersson M., Päbo S., Nilsson T., Peterson P. A. Impaired intracellular transport of class I MHC antigens as a possible means for adenoviruses to evade immune surveillance. Cell. 1985 Nov;43(1):215–222. doi: 10.1016/0092-8674(85)90026-1. [DOI] [PubMed] [Google Scholar]
  2. Arii M., Takada S., Koike K. Identification of three essential regions of hepatitis B virus X protein for trans-activation function. Oncogene. 1992 Mar;7(3):397–403. [PubMed] [Google Scholar]
  3. Benn J., Schneider R. J. Hepatitis B virus HBx protein activates Ras-GTP complex formation and establishes a Ras, Raf, MAP kinase signaling cascade. Proc Natl Acad Sci U S A. 1994 Oct 25;91(22):10350–10354. doi: 10.1073/pnas.91.22.10350. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Brown M. G., Driscoll J., Monaco J. J. Structural and serological similarity of MHC-linked LMP and proteasome (multicatalytic proteinase) complexes. Nature. 1991 Sep 26;353(6342):355–357. doi: 10.1038/353355a0. [DOI] [PubMed] [Google Scholar]
  5. Burgert H. G., Kvist S. An adenovirus type 2 glycoprotein blocks cell surface expression of human histocompatibility class I antigens. Cell. 1985 Jul;41(3):987–997. doi: 10.1016/s0092-8674(85)80079-9. [DOI] [PubMed] [Google Scholar]
  6. Chen H. S., Kaneko S., Girones R., Anderson R. W., Hornbuckle W. E., Tennant B. C., Cote P. J., Gerin J. L., Purcell R. H., Miller R. H. The woodchuck hepatitis virus X gene is important for establishment of virus infection in woodchucks. J Virol. 1993 Mar;67(3):1218–1226. doi: 10.1128/jvi.67.3.1218-1226.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cheong J. H., Yi M., Lin Y., Murakami S. Human RPB5, a subunit shared by eukaryotic nuclear RNA polymerases, binds human hepatitis B virus X protein and may play a role in X transactivation. EMBO J. 1995 Jan 3;14(1):143–150. doi: 10.1002/j.1460-2075.1995.tb06984.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Colgrove R., Simon G., Ganem D. Transcriptional activation of homologous and heterologous genes by the hepatitis B virus X gene product in cells permissive for viral replication. J Virol. 1989 Sep;63(9):4019–4026. doi: 10.1128/jvi.63.9.4019-4026.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Cross J. C., Wen P., Rutter W. J. Transactivation by hepatitis B virus X protein is promiscuous and dependent on mitogen-activated cellular serine/threonine kinases. Proc Natl Acad Sci U S A. 1993 Sep 1;90(17):8078–8082. doi: 10.1073/pnas.90.17.8078. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Doria M., Klein N., Lucito R., Schneider R. J. The hepatitis B virus HBx protein is a dual specificity cytoplasmic activator of Ras and nuclear activator of transcription factors. EMBO J. 1995 Oct 2;14(19):4747–4757. doi: 10.1002/j.1460-2075.1995.tb00156.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Fields S., Song O. A novel genetic system to detect protein-protein interactions. Nature. 1989 Jul 20;340(6230):245–246. doi: 10.1038/340245a0. [DOI] [PubMed] [Google Scholar]
  12. Gaczynska M., Rock K. L., Goldberg A. L. Gamma-interferon and expression of MHC genes regulate peptide hydrolysis by proteasomes. Nature. 1993 Sep 16;365(6443):264–267. doi: 10.1038/365264a0. [DOI] [PubMed] [Google Scholar]
  13. Gaczynska M., Rock K. L., Spies T., Goldberg A. L. Peptidase activities of proteasomes are differentially regulated by the major histocompatibility complex-encoded genes for LMP2 and LMP7. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9213–9217. doi: 10.1073/pnas.91.20.9213. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Genschik P., Philipps G., Gigot C., Fleck J. Cloning and sequence analysis of a cDNA clone from Arabidopsis thaliana homologous to a proteasome alpha subunit from Drosophila. FEBS Lett. 1992 Sep 14;309(3):311–315. doi: 10.1016/0014-5793(92)80796-j. [DOI] [PubMed] [Google Scholar]
  15. Glotzer M., Murray A. W., Kirschner M. W. Cyclin is degraded by the ubiquitin pathway. Nature. 1991 Jan 10;349(6305):132–138. doi: 10.1038/349132a0. [DOI] [PubMed] [Google Scholar]
  16. Glynne R., Powis S. H., Beck S., Kelly A., Kerr L. A., Trowsdale J. A proteasome-related gene between the two ABC transporter loci in the class II region of the human MHC. Nature. 1991 Sep 26;353(6342):357–360. doi: 10.1038/353357a0. [DOI] [PubMed] [Google Scholar]
  17. Goldberg A. L. Functions of the proteasome: the lysis at the end of the tunnel. Science. 1995 Apr 28;268(5210):522–523. doi: 10.1126/science.7725095. [DOI] [PubMed] [Google Scholar]
  18. Goldberg A. L., Rock K. L. Proteolysis, proteasomes and antigen presentation. Nature. 1992 Jun 4;357(6377):375–379. doi: 10.1038/357375a0. [DOI] [PubMed] [Google Scholar]
  19. Guilhot S., Fowler P., Portillo G., Margolskee R. F., Ferrari C., Bertoletti A., Chisari F. V. Hepatitis B virus (HBV)-specific cytotoxic T-cell response in humans: production of target cells by stable expression of HBV-encoded proteins in immortalized human B-cell lines. J Virol. 1992 May;66(5):2670–2678. doi: 10.1128/jvi.66.5.2670-2678.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Gyuris J., Golemis E., Chertkov H., Brent R. Cdi1, a human G1 and S phase protein phosphatase that associates with Cdk2. Cell. 1993 Nov 19;75(4):791–803. doi: 10.1016/0092-8674(93)90498-f. [DOI] [PubMed] [Google Scholar]
  21. Haass C., Pesold-Hurt B., Multhaup G., Beyreuther K., Kloetzel P. M. The Drosophila PROS-28.1 gene is a member of the proteasome gene family. Gene. 1990 Jun 15;90(2):235–241. doi: 10.1016/0378-1119(90)90185-t. [DOI] [PubMed] [Google Scholar]
  22. Hendil K. B., Uerkvitz W. The human multicatalytic proteinase: affinity purification using a monoclonal antibody. J Biochem Biophys Methods. 1991 Feb-Mar;22(2):159–165. doi: 10.1016/0165-022x(91)90028-u. [DOI] [PubMed] [Google Scholar]
  23. Hershko A., Ciechanover A. The ubiquitin system for protein degradation. Annu Rev Biochem. 1992;61:761–807. doi: 10.1146/annurev.bi.61.070192.003553. [DOI] [PubMed] [Google Scholar]
  24. Hochstrasser M., Varshavsky A. In vivo degradation of a transcriptional regulator: the yeast alpha 2 repressor. Cell. 1990 May 18;61(4):697–708. doi: 10.1016/0092-8674(90)90481-s. [DOI] [PubMed] [Google Scholar]
  25. Jentsch S., Schlenker S. Selective protein degradation: a journey's end within the proteasome. Cell. 1995 Sep 22;82(6):881–884. doi: 10.1016/0092-8674(95)90021-7. [DOI] [PubMed] [Google Scholar]
  26. Kekulé A. S., Lauer U., Weiss L., Luber B., Hofschneider P. H. Hepatitis B virus transactivator HBx uses a tumour promoter signalling pathway. Nature. 1993 Feb 25;361(6414):742–745. doi: 10.1038/361742a0. [DOI] [PubMed] [Google Scholar]
  27. Kim C. M., Koike K., Saito I., Miyamura T., Jay G. HBx gene of hepatitis B virus induces liver cancer in transgenic mice. Nature. 1991 May 23;351(6324):317–320. doi: 10.1038/351317a0. [DOI] [PubMed] [Google Scholar]
  28. Kumatori A., Tanaka K., Inamura N., Sone S., Ogura T., Matsumoto T., Tachikawa T., Shin S., Ichihara A. Abnormally high expression of proteasomes in human leukemic cells. Proc Natl Acad Sci U S A. 1990 Sep;87(18):7071–7075. doi: 10.1073/pnas.87.18.7071. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Lee T. H., Elledge S. J., Butel J. S. Hepatitis B virus X protein interacts with a probable cellular DNA repair protein. J Virol. 1995 Feb;69(2):1107–1114. doi: 10.1128/jvi.69.2.1107-1114.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Levrero M., Stemler M., Pasquinelli C., Alberti A., Jean-Jean O., Franco A., Balsano C., Diop D., Brechot C., Melegari M. Significance of anti-HBx antibodies in hepatitis B virus infection. Hepatology. 1991 Jan;13(1):143–149. [PubMed] [Google Scholar]
  31. Liu Z., Batt D. B., Carmichael G. G. Targeted nuclear antisense RNA mimics natural antisense-induced degradation of polyoma virus early RNA. Proc Natl Acad Sci U S A. 1994 May 10;91(10):4258–4262. doi: 10.1073/pnas.91.10.4258. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Löwe J., Stock D., Jap B., Zwickl P., Baumeister W., Huber R. Crystal structure of the 20S proteasome from the archaeon T. acidophilum at 3.4 A resolution. Science. 1995 Apr 28;268(5210):533–539. doi: 10.1126/science.7725097. [DOI] [PubMed] [Google Scholar]
  33. Maguire H. F., Hoeffler J. P., Siddiqui A. HBV X protein alters the DNA binding specificity of CREB and ATF-2 by protein-protein interactions. Science. 1991 May 10;252(5007):842–844. doi: 10.1126/science.1827531. [DOI] [PubMed] [Google Scholar]
  34. Neefjes J. J., Momburg F. Cell biology of antigen presentation. Curr Opin Immunol. 1993 Feb;5(1):27–34. doi: 10.1016/0952-7915(93)90077-6. [DOI] [PubMed] [Google Scholar]
  35. Nordeen S. K. Luciferase reporter gene vectors for analysis of promoters and enhancers. Biotechniques. 1988 May;6(5):454–458. [PubMed] [Google Scholar]
  36. Oldstone M. B. Molecular anatomy of viral persistence. J Virol. 1991 Dec;65(12):6381–6386. doi: 10.1128/jvi.65.12.6381-6386.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Palombella V. J., Rando O. J., Goldberg A. L., Maniatis T. The ubiquitin-proteasome pathway is required for processing the NF-kappa B1 precursor protein and the activation of NF-kappa B. Cell. 1994 Sep 9;78(5):773–785. doi: 10.1016/s0092-8674(94)90482-0. [DOI] [PubMed] [Google Scholar]
  38. Papavassiliou A. G., Treier M., Chavrier C., Bohmann D. Targeted degradation of c-Fos, but not v-Fos, by a phosphorylation-dependent signal on c-Jun. Science. 1992 Dec 18;258(5090):1941–1944. doi: 10.1126/science.1470918. [DOI] [PubMed] [Google Scholar]
  39. Pühler G., Weinkauf S., Bachmann L., Müller S., Engel A., Hegerl R., Baumeister W. Subunit stoichiometry and three-dimensional arrangement in proteasomes from Thermoplasma acidophilum. EMBO J. 1992 Apr;11(4):1607–1616. doi: 10.1002/j.1460-2075.1992.tb05206.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Qadri I., Maguire H. F., Siddiqui A. Hepatitis B virus transactivator protein X interacts with the TATA-binding protein. Proc Natl Acad Sci U S A. 1995 Feb 14;92(4):1003–1007. doi: 10.1073/pnas.92.4.1003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Rechsteiner M., Hoffman L., Dubiel W. The multicatalytic and 26 S proteases. J Biol Chem. 1993 Mar 25;268(9):6065–6068. [PubMed] [Google Scholar]
  42. Rock K. L., Gramm C., Rothstein L., Clark K., Stein R., Dick L., Hwang D., Goldberg A. L. Inhibitors of the proteasome block the degradation of most cell proteins and the generation of peptides presented on MHC class I molecules. Cell. 1994 Sep 9;78(5):761–771. doi: 10.1016/s0092-8674(94)90462-6. [DOI] [PubMed] [Google Scholar]
  43. Runkel L., Fischer M., Schaller H. Two-codon insertion mutations of the HBx define two separate regions necessary for its trans-activation function. Virology. 1993 Dec;197(2):529–536. doi: 10.1006/viro.1993.1626. [DOI] [PubMed] [Google Scholar]
  44. Seto E., Mitchell P. J., Yen T. S. Transactivation by the hepatitis B virus X protein depends on AP-2 and other transcription factors. Nature. 1990 Mar 1;344(6261):72–74. doi: 10.1038/344072a0. [DOI] [PubMed] [Google Scholar]
  45. Siddiqui A., Jameel S., Mapoles J. Expression of the hepatitis B virus X gene in mammalian cells. Proc Natl Acad Sci U S A. 1987 Apr;84(8):2513–2517. doi: 10.1073/pnas.84.8.2513. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Takada S., Koike K. X protein of hepatitis B virus resembles a serine protease inhibitor. Jpn J Cancer Res. 1990 Dec;81(12):1191–1194. doi: 10.1111/j.1349-7006.1990.tb02675.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Tamura T., Lee D. H., Osaka F., Fujiwara T., Shin S., Chung C. H., Tanaka K., Ichihara A. Molecular cloning and sequence analysis of cDNAs for five major subunits of human proteasomes (multi-catalytic proteinase complexes). Biochim Biophys Acta. 1991 May 2;1089(1):95–102. doi: 10.1016/0167-4781(91)90090-9. [DOI] [PubMed] [Google Scholar]
  48. Tanaka K., Tamura T., Yoshimura T., Ichihara A. Proteasomes: protein and gene structures. New Biol. 1992 Mar;4(3):173–187. [PubMed] [Google Scholar]
  49. Truant R., Antunovic J., Greenblatt J., Prives C., Cromlish J. A. Direct interaction of the hepatitis B virus HBx protein with p53 leads to inhibition by HBx of p53 response element-directed transactivation. J Virol. 1995 Mar;69(3):1851–1859. doi: 10.1128/jvi.69.3.1851-1859.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Unger T., Shaul Y. The X protein of the hepatitis B virus acts as a transcription factor when targeted to its responsive element. EMBO J. 1990 Jun;9(6):1889–1895. doi: 10.1002/j.1460-2075.1990.tb08315.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Wang X. W., Forrester K., Yeh H., Feitelson M. A., Gu J. R., Harris C. C. Hepatitis B virus X protein inhibits p53 sequence-specific DNA binding, transcriptional activity, and association with transcription factor ERCC3. Proc Natl Acad Sci U S A. 1994 Mar 15;91(6):2230–2234. doi: 10.1073/pnas.91.6.2230. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Weissman J. S., Sigler P. B., Horwich A. L. From the cradle to the grave: ring complexes in the life of a protein. Science. 1995 Apr 28;268(5210):523–524. doi: 10.1126/science.7725096. [DOI] [PubMed] [Google Scholar]
  53. York I. A., Roop C., Andrews D. W., Riddell S. R., Graham F. L., Johnson D. C. A cytosolic herpes simplex virus protein inhibits antigen presentation to CD8+ T lymphocytes. Cell. 1994 May 20;77(4):525–535. doi: 10.1016/0092-8674(94)90215-1. [DOI] [PubMed] [Google Scholar]
  54. Zervos A. S., Gyuris J., Brent R. Mxi1, a protein that specifically interacts with Max to bind Myc-Max recognition sites. Cell. 1993 Jan 29;72(2):223–232. doi: 10.1016/0092-8674(93)90662-a. [DOI] [PubMed] [Google Scholar]
  55. Zoulim F., Saputelli J., Seeger C. Woodchuck hepatitis virus X protein is required for viral infection in vivo. J Virol. 1994 Mar;68(3):2026–2030. doi: 10.1128/jvi.68.3.2026-2030.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]

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