title: Tetramerization-defects of p53 result in aberrant ubiquitylation and transcriptional activity.
abstract: The tumor suppressor p53 regulates the expression of genes involved in cell cycle progression, senescence and apoptosis. Here, we investigated the effect of single point mutations in the oligomerization domain (OD) on tetramerization, transcription, ubiquitylation and stability of p53. As predicted by docking and molecular dynamics simulations, p53 OD mutants show functional defects on transcription, Mdm2-dependent ubiquitylation and 26S proteasome-mediated degradation. However, mutants unable to form tetramers are well degraded by the 20S proteasome. Unexpectedly, despite the lower structural stability compared to WT p53, p53 OD mutants form heterotetramers with WT p53 when expressed transiently or stably in cells wild type or null for p53. In consequence, p53 OD mutants interfere with the capacity of WT p53 tetramers to be properly ubiquitylated and result in changes of p53-dependent protein expression patterns, including the pro-apoptotic proteins Bax and PUMA under basal and adriamycin-induced conditions. Importantly, the patient derived p53 OD mutant L330R (OD1) showed the more severe changes in p53-dependent gene expression. Thus, in addition to the well-known effects on p53 stability, ubiquitylation defects promote changes in p53-dependent gene expression with implications on some of its functions.
authors.affiliation: Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, Mikeletegi 81, San Sebastián-Donostia 20009, Gipuzkoa, Spain. Electronic address: vlang@inbiomed.org.
authors.forename: Valérie
authors.initials: V
authors.lastname: Lang
authors.affiliation: Joint BSC-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Carrer Jordi Girona 29, 08034 Barcelona, Spain. Electronic address: chiara.pallara@bsc.es.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pallara
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain. Electronic address: azabala@cicbiogune.e.
authors.forename: Amaia
authors.initials: A
authors.lastname: Zabala
authors.affiliation: Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, Mikeletegi 81, San Sebastián-Donostia 20009, Gipuzkoa, Spain. Electronic address: slobato@inbiomed.org.
authors.forename: Sofia
authors.initials: S
authors.lastname: Lobato-Gil
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain. Electronic address: flopitz@cicbiogune.es.
authors.forename: Fernando
authors.initials: F
authors.lastname: Lopitz-Otsoa
authors.affiliation: Centro de Investigación Príncipe Felipe, Eduardo Primo Yúfera 3, 46012 Valencia, Spain. Electronic address: rfarras@cipf.es.
authors.forename: Rosa
authors.initials: R
authors.lastname: Farrás
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain. Electronic address: n.r.e.hjerpe@dundee.ac.uk.
authors.forename: Roland
authors.initials: R
authors.lastname: Hjerpe
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain. Electronic address: monica.atorres@gmail.com.
authors.forename: Monica
authors.initials: M
authors.lastname: Torres-Ramos
authors.affiliation: Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, Mikeletegi 81, San Sebastián-Donostia 20009, Gipuzkoa, Spain. Electronic address: lzabaleta@inbiomed.org.
authors.forename: Lorea
authors.initials: L
authors.lastname: Zabaleta
authors.affiliation: Karlsruher Institute of Technology, Institute of Toxicology and Genetics, Fritz-Erler-Straße 23, 76133 Karlsruhe, Germany. Electronic address: christine.blattner@kit.edu.
authors.forename: Christine
authors.initials: C
authors.lastname: Blattner
authors.affiliation: Center for Interdisciplinary Research, School of Life Sciences, University of Dundee, Dow Street, DD15EH Scotland, United Kingdom. Electronic address: r.t.hay@dundee.ac.uk.
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Hay
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain. Electronic address: rbarrio@cicbiogune.es.
authors.forename: Rosa
authors.initials: R
authors.lastname: Barrio
authors.affiliation: CIC bioGUNE, Ed 801A Parque Tecnológico de Bizkaia, 48160 Derio, Bizkaia, Spain; Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain; Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), P.O. Box 644, E-48080 Bilbao, Spain. Electronic address: acarracedo@cicbiogune.es.
authors.forename: Arkaitz
authors.initials: A
authors.lastname: Carracedo
authors.affiliation: Joint BSC-IRB Research Program in Computational Biology, Life Sciences Department, Barcelona Supercomputing Center, Carrer Jordi Girona 29, 08034 Barcelona, Spain. Electronic address: juanf@bsc.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Fernandez-Recio
authors.affiliation: Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, Mikeletegi 81, San Sebastián-Donostia 20009, Gipuzkoa, Spain. Electronic address: msrodriguez@inbiomed.org.
authors.forename: Manuel S
authors.initials: MS
authors.lastname: Rodríguez
authors.affiliation: Ubiquitylation and Cancer Molecular Biology Laboratory, Inbiomed, Mikeletegi 81, San Sebastián-Donostia 20009, Gipuzkoa, Spain. Electronic address: faillet@inbiomed.org.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Aillet
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D062105:Molecular Docking Simulation; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D055503:Protein Multimerization; D059748:Proteolysis; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D046988:Proteasome Endopeptidase Complex
keywords: Oligomerization; Proteasome; Transcription; Ubiquitylation; p53