title: Cullin3-KLHL15 ubiquitin ligase mediates CtIP protein turnover to fine-tune DNA-end resection.
abstract: Human CtIP is a decisive factor in DNA double-strand break repair pathway choice by enabling DNA-end resection, the first step that differentiates homologous recombination (HR) from non-homologous end-joining (NHEJ). To coordinate appropriate and timely execution of DNA-end resection, CtIP function is tightly controlled by multiple protein-protein interactions and post-translational modifications. Here, we identify the Cullin3 E3 ligase substrate adaptor Kelch-like protein 15 (KLHL15) as a new interaction partner of CtIP and show that KLHL15 promotes CtIP protein turnover via the ubiquitin-proteasome pathway. A tripeptide motif (FRY) conserved across vertebrate CtIP proteins is essential for KLHL15-binding; its mutation blocks KLHL15-dependent CtIP ubiquitination and degradation. Consequently, DNA-end resection is strongly attenuated in cells overexpressing KLHL15 but amplified in cells either expressing a CtIP-FRY mutant or lacking KLHL15, thus impacting the balance between HR and NHEJ. Collectively, our findings underline the key importance and high complexity of CtIP modulation for genome integrity.
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Lorenza P
authors: LP
authors: Ferretti
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Sarah-Felicitas
authors: SF
authors: Himmels
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Anika
authors: A
authors: Trenner
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Christina
authors: C
authors: Walker
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Christine
authors: C
authors: von Aesch
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Aline
authors: A
authors: Eggenschwiler
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Olga
authors: O
authors: Murina
authors: ETH Zurich, Institute of Biochemistry, Department of Biology, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
authors: Radoslav I
authors: RI
authors: Enchev
authors: ETH Zurich, Institute of Biochemistry, Department of Biology, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
authors: Matthias
authors: M
authors: Peter
authors: Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Cuesta, La Laguna, Tenerife, Spain.
authors: Raimundo
authors: R
authors: Freire
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Antonio
authors: A
authors: Porro
authors: University of Zurich, Institute of Molecular Cancer Research, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
authors: Alessandro A
authors: AA
authors: Sartori
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D059766:DNA End-Joining Repair; D004706:Endodeoxyribonucleases; D059765:Homologous Recombination / Q000235:genetics*; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs / Q000235:genetics; D059748:Proteolysis; D054875:Ubiquitination / Q000235:genetics*
chemical_list: C503645:CUL3 protein, human; D002352:Carrier Proteins; D044842:Cullin Proteins; C503716:KLHL15 protein, human; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D004706:Endodeoxyribonucleases; C410741:RBBP8 protein, human