Subunit of the '20S' proteasome (multicatalytic proteinase) encoded by the major histocompatibility complex.
Cytotoxic T lymphocytes recognize fragments (peptides) of protein antigens presented by major histocompatibility complex (MHC) class I molecules. In general, the peptides are derived from cytosolic proteins and are then transported to the endoplasmic reticulum where they assemble with the MHC class I heavy chains and beta 2-microglobulin to form stable and functional class I molecules. The proteases involved in the generation of these peptides are unknown. One candidate is the proteasome, a nonlysosomal proteinase complex abundantly present in the cytosol. Proteasomes have several proteolytically active sites and are complexes of high relative molecular mass (Mr about 600K), consisting of about 20-30 subunits with Mrs between 15 and 30K. Here we show that at least one of these subunits is encoded by the mouse MHC in the region between the K locus and the MHC class II region, and inducible by interferon-gamma. This raises the intriguing possibility that the MHC encodes not only the MHC class I molecules themselves but also proteases involved in the formation of MHC-binding peptides.
Institute for Immunology and Genetics, German Cancer Research Center, Heidelberg.
V
V
Ortiz-Navarrete
A
A
Seelig
M
M
Gernold
S
S
Frentzel
P M
PM
Kloetzel
G J
GJ
Hämmerling
D000818:Animals; D001692:Biological Transport; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D005805:Genes, MHC Class I / Q000235:genetics*; D006183:H-2 Antigens / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D014407:Tumor Cells, Cultured
D006183:H-2 Antigens; D009097:Multienzyme Complexes; D010446:Peptide Fragments; D007371:Interferon-gamma; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex