RESUMEN

Homologous recombination (HR) and nonhomologous end joining (NHEJ) are two distinct DNA double-stranded break (DSB) repair pathways. Here, we report that DNA-dependent protein kinase (DNA-PK), the core component of NHEJ, partnering with DNA-damage checkpoint kinases ataxia telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR), regulates HR repair of DSBs. The regulation was accomplished through modulation of the p53 and replication protein A (RPA) interaction. We show that upon DNA damage, p53 and RPA were freed from a p53-RPA complex by simultaneous phosphorylations of RPA at the N-terminus of RPA32 subunit by DNA-PK and of p53 at Ser37 and Ser46 in a Chk1/Chk2-independent manner by ATR and ATM, respectively. Neither the phosphorylation of RPA nor of p53 alone could dissociate p53 and RPA. Furthermore, disruption of the release significantly compromised HR repair of DSBs. Our results reveal a mechanism for the crosstalk between HR repair and NHEJ through the co-regulation of p53-RPA interaction by DNA-PK, ATM and ATR.

Asunto(s)

Proteínas de Ciclo Celular/metabolismo , Proteína Quinasa Activada por ADN/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Reparación del ADN por Recombinación , Proteína de Replicación A/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Daño del ADN , Proteína Quinasa Activada por ADN/genética , Proteínas de Unión al ADN/genética , Genes p53 , Humanos , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Proteína de Replicación A/genética , Transfección , Proteína p53 Supresora de Tumor/genética , Proteínas Supresoras de Tumor/genética