Identification of MECL-1 (LMP-10) as the third IFN-gamma-inducible proteasome subunit.
We show that six proteasome-associated proteins are induced by IFN-gamma, corresponding to three proteasome beta-type subunits and their precursors: the MHC-linked subunits (LMP-2 and LMP-7) and LMP-10. Concurrently, incorporation of LMP-9, LMP-17, and LMP-19 into proteasomes is reduced. LMP-10 appears to be the product of a previously cloned proteasome subunit gene, MECL-1. MECL-1 transcription is increased in the presence of IFN-gamma, whereas the transcription of two other proteasome genes, Lmp-15 and Lmp-3, is not affected. The three IFN-gamma-inducible subunits and their constitutively expressed counterparts contain most or all of the catalytic sites of the proteasome. Independent assortment of LMP-2, LMP-7, and LMP-10 into different proteasome complexes may thus generate up to 36 unique proteasome subsets. This may increase the repertoire of potentially antigenic peptides for presentation by MHC class I.
Nandi
D
D
Department of Molecular Genetics; Howard Hughes Medical Insitute, University of Cincinnati, Ohio 452167, USA.
Jiang
H
H
Monaco
J J
JJ
D000818:Animals; D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D046988:Proteasome Endopeptidase Complex; D011498:Protein Precursors / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D009097:Multienzyme Complexes; D011498:Protein Precursors; D011994:Recombinant Proteins; D007371:Interferon-gamma; D003546:Cysteine Endopeptidases; C098948:PSMB10 protein, human; D046988:Proteasome Endopeptidase Complex; C490920:Psmb10 protein, mouse