title: Ubiquitin-specific peptidase 20 regulates Rad17 stability, checkpoint kinase 1 phosphorylation and DNA repair by homologous recombination.
abstract: Rad17 is a subunit of the Rad9-Hus1-Rad1 clamp loader complex, which is required for Chk1 activation after DNA damage. Rad17 has been shown to be regulated by the ubiquitin-proteasome system. We have identified a deubiquitylase, USP20 that is required for Rad17 protein stability in the steady-state and post DNA damage. We demonstrate that USP20 and Rad17 interact, and that this interaction is enhanced by UV exposure. We show that USP20 regulation of Rad17 is at the protein level in a proteasome-dependent manner. USP20 depletion results in poor activation of Chk1 protein by phosphorylation, consistent with Rad17 role in ATR-mediated phosphorylation of Chk1. Similar to other DNA repair proteins, USP20 is phosphorylated post DNA damage, and its depletion sensitizes cancer cells to damaging agents that form blocks ahead of the replication forks. Similar to Chk1 and Rad17, which enhance recombinational repair of collapsed replication forks, we demonstrate that USP20 depletion impairs DNA double strand break repair by homologous recombination. Together, our data establish a new function of USP20 in genome maintenance and DNA repair.
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Ilanchezhian
authors.initials: I
authors.lastname: Shanmugam
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abbas
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Farhan
authors.initials: F
authors.lastname: Ayoub
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Susan
authors.initials: S
authors.lastname: Mirabal
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Manal
authors.initials: M
authors.lastname: Bsaili
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Caulder
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02215.
authors.forename: David M
authors.initials: DM
authors.lastname: Weinstock
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131.
authors.forename: Alan E
authors.initials: AE
authors.lastname: Tomkinson
authors.affiliation: Department of Medicine, University of Florida, Gainesville, Florida 32610, and.
authors.forename: Robert
authors.initials: R
authors.lastname: Hromas
authors.affiliation: Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131,. Electronic address: moshaheen@salud.unm.edu.
authors.forename: Monte
authors.initials: M
authors.lastname: Shaheen
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D000071877:Checkpoint Kinase 1; D053903:DNA Breaks, Double-Stranded; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation / Q000502:physiology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D059767:Recombinational DNA Repair / Q000502:physiology*; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C113575:Rad17 protein, human; C459591:USP20 protein, human; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D043222:Ubiquitin Thiolesterase
keywords: Checkpoint Control; Cisplatin; DNA Damage Response; DNA Repair; Deubiquitylation (Deubiquitination); Homologous Recombination; USP20; chk1; rad17