title: RNF138 interacts with RAD51D and is required for DNA interstrand crosslink repair and maintaining chromosome integrity.
abstract: The RAD51 family is integral for homologous recombination (HR) mediated DNA repair and maintaining chromosome integrity. RAD51D, the fourth member of the family, is a known ovarian cancer susceptibility gene and required for the repair of interstrand crosslink DNA damage and preserving chromosomal stability. In this report, we describe the RNF138 E3 ubiquitin ligase that interacts with and ubiquitinates the RAD51D HR protein. RNF138 is a member of an E3 ligase family that contains an amino-terminal RING finger domain and a putative carboxyl-terminal ubiquitin interaction motif. In mammalian cells, depletion of RNF138 increased the stability of the RAD51D protein, suggesting that RNF138 governs ubiquitin-proteasome-mediated degradation of RAD51D. However, RNF138 depletion conferred sensitivity to DNA damaging agents, reduced RAD51 focus formation, and increased chromosomal instability. Site-specific mutagenesis of the RNF138 RING finger domain demonstrated that it was necessary for RAD51D ubiquitination. Presence of RNF138 also enhanced the interaction between RAD51D and a known interacting RAD51 family member XRCC2 in a yeast three-hybrid assay. Therefore, RNF138 is a newly identified regulatory component of the HR mediated DNA repair pathway that has implications toward understanding how ubiquitination modifies the functions of the RAD51 paralog protein complex.
authors.affiliation: Department of Translational Hematology and Oncology Research, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH 44195, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Yard
authors.affiliation: Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Reilly
authors.affiliation: Department of Pharmacy Services, Greenville Health System, Greenville, SC 29615, USA.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Bedenbaugh
authors.affiliation: Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC 29208, USA. Electronic address: pittman@sccp.sc.edu.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Pittman
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002877:Chromosomes, Human / Q000235:genetics*; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D059765:Homologous Recombination; D006801:Humans; D051379:Mice; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D059748:Proteolysis; D051135:Rad51 Recombinase / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D004268:DNA-Binding Proteins; D020033:Protein Isoforms; C113187:XRCC2 protein, human; C000618180:RNF138 protein, mouse; D044767:Ubiquitin-Protein Ligases; D051135:Rad51 Recombinase; D046988:Proteasome Endopeptidase Complex
keywords: Chromosome integrity; DNA double-stranded breaks; DNA interstrand crosslinks; DNA repair; E3 ligase; Homologous recombination; RAD51D; RNF138; Ubiquitination