title: PIAS-1 is a checkpoint regulator which affects exit from G1 and G2 by sumoylation of p73.
abstract: p73 is a recently described member of the p53 family, and, like p53, it undergoes a number of posttranslational modifications. Here we show, by yeast two-hybrid screening, pull-down assays, and coimmunoprecipitation, that p73alpha, -beta, and -gamma bind to the protein inhibitor of activated STAT-1 (PIAS-1) and that this binding stabilizes p73. PIAS-1 also sumoylates p73alpha, although not the C-terminally truncated isoforms p73beta and -gamma, and this requires the RING finger domain of PIAS-1. The DeltaNp73alpha isoform can also bind, and be sumoylated by, PIAS-1. PIAS-1-mediated sumoylation decreases p73 transcriptional activity on several target promoters, such as Bax. p73 is colocalized in the nucleus with PIAS-1, and sumoylated p73 is located exclusively in the nuclear matrix. PIAS-1 is expressed predominantly during S phase, and PIAS-1 overexpression reduces p73-mediated transcription of p21, with a reduction of cells in G(1) and cell cycle reentry. Inhibition of endogenous PIAS-1 by RNA interference reduces the proportion of cells in S phase and induces G(2) arrest. These data suggest that PIAS-1, acting partly through binding and sumoylation of p73, is an important component of the cell cycle machinery.
authors.affiliation: Medical Research Council, Toxicology Unit, Hodgkin Building, Leicester University, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom.
authors.forename: Eliana
authors.initials: E
authors.lastname: Munarriz
authors.forename: Daniela
authors.initials: D
authors.lastname: Barcaroli
authors.forename: Anastasis
authors.initials: A
authors.lastname: Stephanou
authors.forename: Paul A
authors.initials: PA
authors.lastname: Townsend
authors.forename: Carine
authors.initials: C
authors.lastname: Maisse
authors.forename: Alessandro
authors.initials: A
authors.lastname: Terrinoni
authors.forename: Michael H
authors.initials: MH
authors.lastname: Neale
authors.forename: Seamus J
authors.initials: SJ
authors.lastname: Martin
authors.forename: David S
authors.initials: DS
authors.lastname: Latchman
authors.forename: Richard A
authors.initials: RA
authors.lastname: Knight
authors.forename: Gerry
authors.initials: G
authors.lastname: Melino
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Laurenzi
mesh_terms: D015153:Blotting, Western; D018288:Carcinoma, Small Cell / Q000473:pathology; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase; D016195:G2 Phase; D016147:Genes, Tumor Suppressor; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008175:Lung Neoplasms / Q000473:pathology; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012516:Osteosarcoma / Q000473:pathology; D011233:Precipitin Tests; D050828:Protein Inhibitors of Activated STAT; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D011994:Recombinant Proteins / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C106529:PIAS1 protein, human; D050828:Protein Inhibitors of Activated STAT; D020033:Protein Isoforms; D011994:Recombinant Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D008156:Luciferases; D005982:Glutathione Transferase