Promotion of RAD51-Mediated Homologous DNA Pairing by the RAD51AP1-UAF1 Complex

  • Cell Rep. 2016 Jun 7;15(10):2118-2126. doi: 10.1016/j.celrep.2016.05.007.
Fengshan Liang  1 ,  Simonne Longerich  1 ,  Adam S Miller  1 ,  Caroline Tang  2 ,  Olga Buzovetsky  1 ,  Yong Xiong  1 ,  David G Maranon  3 ,  Claudia Wiese  3 ,  Gary M Kupfer  4 ,  Patrick Sung  5
Affiliations
  • 1. Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
  • 2. Section of Hematology-Oncology, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA.
  • 3. Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
  • 4. Section of Hematology-Oncology, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA. Electronic address: [email protected].
  • 5. Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA. Electronic address: [email protected].
PMID: 27239033 DOI: 10.1016/j.celrep.2016.05.007
Abstract

The UAF1-USP1 complex deubiquitinates FANCD2 during execution of the Fanconi anemia DNA damage response pathway. As such, UAF1 depletion results in persistent FANCD2 ubiquitination and DNA damage hypersensitivity. UAF1-deficient cells are also impaired for DNA repair by homologous recombination. Herein, we show that UAF1 binds DNA and forms a dimeric complex with RAD51AP1, an accessory factor of the RAD51 recombinase, and a trimeric complex with RAD51 through RAD51AP1. Two small ubiquitin-like modifier (SUMO)-like domains in UAF1 and a SUMO-interacting motif in RAD51AP1 mediate complex formation. Importantly, UAF1 enhances RAD51-mediated homologous DNA pairing in a manner that is dependent on complex formation with RAD51AP1 but independent of USP1. Mechanistically, RAD51AP1-UAF1 co-operates with RAD51 to assemble the synaptic complex, a critical nucleoprotein intermediate in homologous recombination, and cellular studies reveal the biological significance of the RAD51AP1-UAF1 protein complex. Our findings provide insights into an apparently USP1-independent role of UAF1 in genome maintenance.