title: The Deubiquitinase USP9X Maintains DNA Replication Fork Stability and DNA Damage Checkpoint Responses by Regulating CLASPIN during S-Phase.
abstract: Coordination of the multiple processes underlying DNA replication is key for maintaining genome stability and preventing tumorigenesis. CLASPIN, a critical player in replication fork stabilization and checkpoint responses, must be tightly regulated during the cell cycle to prevent the accumulation of DNA damage. In this study, we used a quantitative proteomics approach and identified USP9X as a novel CLASPIN-interacting protein. USP9X is a deubiquitinase involved in multiple signaling and survival pathways whose tumor suppressor or oncogenic activity is highly context dependent. We found that USP9X regulated the expression and stability of CLASPIN in an S-phase-specific manner. USP9X depletion profoundly impairs the progression of DNA replication forks, causing unscheduled termination events with a frequency similar to CLASPIN depletion, resulting in excessive endogenous DNA damage. Importantly, restoration of CLASPIN expression in USP9X-depleted cells partially suppressed the accumulation of DNA damage. Furthermore, USP9X depletion compromised CHK1 activation in response to hydroxyurea and UV, thus promoting hypersensitivity to drug-induced replication stress. Taken together, our results reveal a novel role for USP9X in the maintenance of genomic stability during DNA replication and provide potential mechanistic insights into its tumor suppressor role in certain malignancies. Cancer Res; 76(8); 2384-93. ©2016 AACR.
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: Edel
authors.initials: E
authors.lastname: McGarry
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Gaboriau
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Rainey
authors.affiliation: IFOM-FIRC Institute of Molecular Oncology, Milan, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Restuccia
authors.affiliation: IFOM-FIRC Institute of Molecular Oncology, Milan, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Bachi
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland. corrado.santocanale@nuigalway.ie.
authors.forename: Corrado
authors.initials: C
authors.lastname: Santocanale
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D045744:Cell Line, Tumor; D004249:DNA Damage / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D006801:Humans; D016196:S Phase; D043222:Ubiquitin Thiolesterase / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C488158:CLSPN protein, human; C506234:USP9X protein, human; D043222:Ubiquitin Thiolesterase