Immunogenetics

, Volume 46, Issue 4, pp 337–344

PA28 subunits of the mouse proteasome: primary structures and chromosomal localization of the genes

  • Eman Kandil
  • Keiko Kohda
  • Teruo Ishibashi
  • Keiji Tanaka
  • M. Kasahara
ORIGINAL PAPER

DOI: 10.1007/s002510050281

Cite this article as:
Kandil, E., Kohda, K., Ishibashi, T. et al. Immunogenetics (1997) 46: 337. doi:10.1007/s002510050281

Abstract

 The 20S proteasome is a multi-subunit protease responsible for the production of peptides presented by major histocompatibility complex (MHC) class I molecules. Recent evidence indicates that an interferon-γ (IFN-γ)-inducible PA28 activator complex enhances the generation of class I binding peptides by altering the cleavage pattern of the proteasome. In the present study, we determined the primary structures of the mouse PA28 α- and β-subunits. The deduced amino acid sequences of the α- and β-subunits were 49% identical. We also determined the primary structure of the mouse PA28 γ-subunit (Ki antigen), a protein of unknown function structurally related to the α- and β-subunits. The amino acid sequence identity of the γ-subunit to the α- and β-subunits was 40% and 32%, respectively. Interspecific backcross mapping showed that the mouse genes coding for the α- and β-subunits (designated Psme1 and Psme2, respectively) are tightly linked and map close to the Atp5g1 locus on chromosome 14. Thus, unlike the LMP2 and LMP7 subunits, the IFN-γ-inducible subunits of PA28 are encoded outside the MHC. The gene coding for the γ-subunit (designated Psme3) was mapped to the vicinity of the Brca1 locus on chromosome 11. A computer search of the DNA databases identified a γ-subunit-like protein in ticks and Caenorhabditis elegans, the organisms with no adaptive immune system. It appears that the IFN-γ-inducible α- and β-subunits emerged by gene duplication from a γ-subunit-like precursor.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Eman Kandil
    • 1
  • Keiko Kohda
    • 1
  • Teruo Ishibashi
    • 1
  • Keiji Tanaka
    • 2
  • M. Kasahara
    • 1
  1. 1.Department of Biochemistry, Hokkaido University School of Medicine, Sapporo 060, JapanJP
  2. 2.Tokyo Metropolitan Institute of Medical Science, Tokyo 113, JapanJP
  3. 3.CREST, Japan Science and Technology Corporation (JST), Tokyo 101, JapanJP

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