IRF-1 mediates upregulation of LMP7 by IFN-γ and concerted expression of immunosubunits of the proteasome

Shin Namiki, Tetsuya Nakamura, Shigeru Oshima, Motomi Yamazaki, Yuko Sekine, Kiichiro Tsuchiya, Ryuichi Okamoto, Takanori Kanai, Mamoru Watanabe

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


An immunoproteasome subunit low molecular weight protein 7 (LMP7) plays critical roles in major histocompatibility complex class I antigen processing; however, the mechanism for its expression has remained unclear. We demonstrate that interferon (IFN) regulatory factor-1 (IRF-1) has a pivotal role in IFN-γ-dependent LMP7 expression, as was shown for the other two immunosubunits. A tetracycline-inducible system for IRF-1 revealed its function in the LMP7 expression, and a genomic region functionally interacting with IRF-1 was also determined. Furthermore, the role of IRF-1 in IFN-γ-inducible LMP7 transcription was confirmed by employing small interfering RNA experiments and IRF-1-/- mice. These results suggest that IRF-1 acts as a master regulator for the concerted expression of immunoproteasome components.

Original languageEnglish
Pages (from-to)2781-2787
Number of pages7
JournalFEBS Letters
Issue number13
Publication statusPublished - 2005 May 23
Externally publishedYes


  • Immunoproteasome
  • Interferon regulatory factor-1
  • Low molecular weight protein 2
  • Low molecular weight protein 7
  • Major histocompatibility complex class I antigen processing
  • Multicatalytic endopeptidase complex-like 1

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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