title: Enhanced deacetylation of p53 by the anti-apoptotic protein HSCO in association with histone deacetylase 1.
abstract: HSCO (hepatoma subtracted-cDNA library clone one, also called ETHE1) was originally identified by its frequent overexpression in hepatocellular carcinomas. HSCO inhibits function of NF-kappaB by binding to RelA and accelerating its export from the nucleus. We show here that HSCO exhibits anti-apoptotic activity in cells exposed to DNA-damaging agents by suppressing transcriptional activity of p53. Induction of pro-apoptotic genes, Noxa, Perp, PIG3, and Bax were suppressed in cells over-expressing HSCO. By increasing ubiquitylation and degradation of p53, HSCO reduces p53 protein levels. HSCO specifically associates with histone deacetylase 1 (HDAC1) independently of Mdm2 and facilitates deacetylation of p53 at Lys-373/382 by HDAC1. The metallo-beta-lactamase family consensus sequence in HSCO is important for its effect on p53 deacetylation. Co-immunoprecipitation and immunofluorescence studies suggested that HSCO, HDAC1, and p53 form a complex in the nucleus. Thus, HSCO is a cofactor that increases the deacetylase activity of HDAC1 toward p53, leading to suppression of apoptosis. Treatment of hepatocellular carcinomas that retain wild-type p53 and overexpress HSCO with anti-HSCO agents might re-establish the p53 response and revert chemoresistance.
authors.affiliation: Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Kyoto 606-8507, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Higashitsuji
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Higashitsuji
authors.forename: Tomoko
authors.initials: T
authors.lastname: Masuda
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Itoh
authors.forename: Jun
authors.initials: J
authors.lastname: Fujita
mesh_terms: D000107:Acetylation; D000818:Animals; D017209:Apoptosis; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D016147:Genes, Tumor Suppressor; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C494826:BAX protein, human; C483228:ETHE1 protein, human; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; D029543:Nucleocytoplasmic Transport Proteins; C416404:PERP protein, human; C498702:PMAIP1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C498143:RELA protein, human; C411296:TP53I3 protein, human; D051996:Transcription Factor RelA; D016159:Tumor Suppressor Protein p53; D014452:Ubiquitins; D051028:bcl-2-Associated X Protein; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases