Cell cycle-dependent phosphorylation regulates RECQL4 pathway choice and ubiquitination in DNA double-strand break repair

• Published in: Nature communications Vol. 8; no. 1; pp. 2039 - 14
• Main Authors: Lu, Huiming, Shamanna, Raghavendra A., de Freitas, Jessica K., Okur, Mustafa, Khadka, Prabhat, Kulikowicz, Tomasz, Holland, Priscella P., Tian, Jane, Croteau, Deborah L., Davis, Anthony J., Bohr, Vilhelm A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.12.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45/147; 631/80/304; Cell Cycle; Cell Line, Tumor; Cell survival; Cullin Proteins - genetics; Cullin Proteins - metabolism; Cyclin-dependent kinase 2; Cyclin-Dependent Kinases - genetics; Cyclin-Dependent Kinases - metabolism; Deoxyribonucleic acid; DNA; DNA Breaks, Double-Stranded; DNA damage; DNA End-Joining Repair; DNA helicase; DNA repair; Double-strand break repair; Genetic recombination; Genomes; HEK293 Cells; Homologous recombination; Homology; Humanities and Social Sciences; Humans; Ionizing radiation; Kinases; Ku Autoantigen - genetics; Ku Autoantigen - metabolism; MRE11 protein; multidisciplinary; Non-homologous end joining; Phosphorylation; Protein Binding; Recombinational DNA Repair; RecQ Helicases - genetics; RecQ Helicases - metabolism; Recruitment; Repair; RNA Interference; Rothmund-Thomson syndrome; Science; Science (multidisciplinary); Senescence; Ubiquitin; Ubiquitin-protein ligase; Ubiquitination
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02146-3

Pathway choice within DNA double-strand break (DSB) repair is a tightly regulated process to maintain genome integrity. RECQL4, deficient in Rothmund-Thomson Syndrome, promotes the two major DSB repair pathways, non-homologous end joining (NHEJ) and homologous recombination (HR). Here we report that RECQL4 promotes and coordinates NHEJ and HR in different cell cycle phases. RECQL4 interacts with Ku70 to promote NHEJ in G1 when overall cyclin-dependent kinase (CDK) activity is low. During S/G2 phases, CDK1 and CDK2 (CDK1/2) phosphorylate RECQL4 on serines 89 and 251, enhancing MRE11/RECQL4 interaction and RECQL4 recruitment to DSBs. After phosphorylation, RECQL4 is ubiquitinated by the DDB1-CUL4A E3 ubiquitin ligase, which facilitates its accumulation at DSBs. Phosphorylation of RECQL4 stimulates its helicase activity, promotes DNA end resection, increases HR and cell survival after ionizing radiation, and prevents cellular senescence. Collectively, we propose that RECQL4 modulates the pathway choice of NHEJ and HR in a cell cycle-dependent manner. DNA double-strand break (DSB) repair is a tightly regulated process that can occur via non-homologous end joining (NHEJ) or homologous recombination (HR). Here, the authors investigate how RECQL4 modulates DSB repair pathway choice by differentially regulating NHEJ and HR in a cell cycle-dependent manner.