Abstract
Production of antigenic peptides that serve as MHC class I ligands is essential for initiation of cell-mediated immunity. Accumulating evidence indicates that the proteasome, a large multisubunit protein deg radative machine in eukaryotes, functions as a processing enzyme responsible for the generation of MHC class I ligands. This processing system is elaborately regulated by various immunomodulatory cytokines. In particular, interferon-gamma induces the formation of immunoproteasomes and a recently identified proteasomal regulatory factor. PA28, which in concert contribute to efficient production of MHC class I ligands. Many of the MHC-encoded genes including LMP appear to have emerged by an ancient chromosomal duplication, suggesting that modifications and renewal of pre-existing non-immune genes were instrumental in the emergence of adaptive immunity.
Publication types
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Amino Acid Sequence
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Animals
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Antigen Presentation / immunology*
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Chromosome Mapping
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Cysteine Endopeptidases / chemistry
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Cysteine Endopeptidases / genetics
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Cysteine Endopeptidases / immunology*
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Enzyme Activation
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Gene Expression Regulation
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Histocompatibility Antigens Class I / immunology*
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Humans
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Interferon-gamma / immunology*
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Ligands
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Molecular Sequence Data
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Multienzyme Complexes / chemistry
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Multienzyme Complexes / genetics
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Multienzyme Complexes / immunology*
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Muscle Proteins*
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Proteasome Endopeptidase Complex
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Protein Conformation
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Proteins / genetics
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Proteins / immunology*
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Ubiquitins / immunology
Substances
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Histocompatibility Antigens Class I
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Ligands
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Multienzyme Complexes
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Muscle Proteins
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PSME1 protein, human
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Proteins
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Ubiquitins
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Interferon-gamma
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex