title: Inactivating UBE2M impacts the DNA damage response and genome integrity involving multiple cullin ligases.
abstract: Protein neddylation is involved in a wide variety of cellular processes. Here we show that the DNA damage response is perturbed in cells inactivated with an E2 Nedd8 conjugating enzyme UBE2M, measured by RAD51 foci formation kinetics and cell based DNA repair assays. UBE2M knockdown increases DNA breakages and cellular sensitivity to DNA damaging agents, further suggesting heightened genomic instability and defective DNA repair activity. Investigating the downstream Cullin targets of UBE2M revealed that silencing of Cullin 1, 2, and 4 ligases incurred significant DNA damage. In particular, UBE2M knockdown, or defective neddylation of Cullin 2, leads to a blockade in the G1 to S progression and is associated with delayed S-phase dependent DNA damage response. Cullin 4 inactivation leads to an aberrantly high DNA damage response that is associated with increased DNA breakages and sensitivity of cells to DNA damaging agents, suggesting a DNA repair defect is associated. siRNA interrogation of key Cullin substrates show that CDT1, p21, and Claspin are involved in elevated DNA damage in the UBE2M knockdown cells. Therefore, UBE2M is required to maintain genome integrity by activating multiple Cullin ligases throughout the cell cycle.
authors.affiliation: Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Scott
authors.initials: S
authors.lastname: Cukras
authors.affiliation: Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Morffy
authors.affiliation: Department of Cellular & Molecular Medicine, College of Medicine, Chosun University, Gwangju, Republic of Korea.
authors.forename: Takbum
authors.initials: T
authors.lastname: Ohn
authors.affiliation: Department of Cell Biology, Microbiology, and Molecular Biology, College of Arts and Sciences, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Younghoon
authors.initials: Y
authors.lastname: Kee
mesh_terms: D002453:Cell Cycle / Q000235:genetics; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D020868:Gene Silencing; D042822:Genomic Instability; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics; D051135:Rad51 Recombinase / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics* / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics
chemical_list: C467199:CDT1 protein, human; C105153:CUL2 protein, human; D018797:Cell Cycle Proteins; D044842:Cullin Proteins; C429530:DTL protein, human; D009687:Nuclear Proteins; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D051135:Rad51 Recombinase; C000596156:UBE2M protein, human