title: PA200, a nuclear proteasome activator involved in DNA repair.
abstract: We have identified a novel 200 kDa nuclear protein that activates the proteasome. The protein, which we call PA200, has been purified to homogeneity from bovine testis and has been shown to activate proteasomal hydrolysis of peptides, but not proteins. Following gamma-irradiation of HeLa cells the uniform nuclear distribution of PA200 changes to a strikingly punctate pattern, a behavior characteristic of many DNA repair proteins. Homologs of PA200 are present in worms, plants and yeast. Others have shown that mutation of yeast PA200 results in hypersensitivity to bleomycin, and exposure of yeast to DNA damaging agents induces the PA200 message. Taken together, these findings implicate PA200 in DNA repair, possibly by recruiting proteasomes to double strand breaks.
authors.affiliation: Department of Biochemistry, University of Utah, 50 N Medical Drive, Salt Lake City, UT 84132, USA.
authors.forename: Vicença
authors.initials: V
authors.lastname: Ustrell
authors.forename: Laura
authors.initials: L
authors.lastname: Hoffman
authors.forename: Gregory
authors.initials: G
authors.lastname: Pratt
authors.forename: Martin
authors.initials: M
authors.lastname: Rechsteiner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000737:chemistry; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D018076:DNA, Complementary / Q000235:genetics; D004789:Enzyme Activation; D005720:Gamma Rays; D006367:HeLa Cells / Q000201:enzymology / Q000528:radiation effects; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D009928:Organ Specificity; D010455:Peptides / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification; D011817:Rabbits; D013045:Species Specificity; D013737:Testis / Q000737:chemistry
chemical_list: D018076:DNA, Complementary; D009097:Multienzyme Complexes; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C574231:Pa200 protein, mouse; D010455:Peptides; D020033:Protein Isoforms; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex