Replacement of proteasome subunits X and Y by LMP7 and LMP2 induced by interferon‐γ for acquirement of the functional diversity responsible for antigen processing

FEBS Letters

Takashina, Makoto¹  Hendil, Klavs B.²  Tanaka, Keiji³  Tamura, Tomohiro³  Kristensen, Poul²  Akiyama, Kinya⁴  Kagawa, Susumu⁴  Ichihara, Akira³  Shimbara, Naoki¹ 

[1] Biomaterial Research Institute, 1 Taya-cho, Sakae-ku, Yokohama 244, Japan;August Krogh Institute, University of Copenhagen, 13 Universitetsparken, DK 2100 Copenhagen 0, Denmark;Institute for Enzyme Research, The University of Tokushima, Tokushima 770, Japan;Department of Urology, School of Medicine The University of Tokushima, Tokushima 770, Japan

关键词: Antigen processing;    MHC class I;    Interferon-γ;    Multicatalytic proteinase;    Proteasome;    Ubiquitin;   

DOI  :  10.1016/0014-5793(94)80612-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Proteasomes catalyze the non-lysosomal, ATP-dependent selective breakdown of ubiquitinated proteins and are thought to be responsible for MHC class I-restricted antigen presentation. Recently, we reported that gamma interferon (IFN-γ) induced not only marked synthesis of the MHC-encoded proteasome subunits LMP2 and LMP7, but also almost complete loss of two unidentified proteasome subunits tentatively designated as X and Y in various human cells. Here, we show that subunit X is a new proteasomal subunit highly homologous to LMP7, and that subunit Y is identical to the LMP2-related proteasomal subunit delta. Thus, IFN-γ appears to induce subunit replacements of X and Y by LMP7 and LMP2, respectively, producing 'immuno-proteasomes' with the functional diversity responsible for processing of endogenous antigens.

【 授权许可】

Unknown