Endurance training limits the functional alterations of heart rat mitochondria submitted to in vitro anoxia-reoxygenation

Studies analysing the effect of endurance training on heart mitochondrial function submitted to in vitro anoxia-reoxygenation (A-R) are missing. The present study aimed to investigate the effect of moderate endurance treadmill training (14 weeks) against rat heart mitochondrial dysfunction induced by in vitro A-R.Methodshttp://www.sciencedirect.com/science/article/B6T16-4GMGW4S-3/1/c6e94a0780899cd96af4b3b36ca7a92

53BP1 mediates productive and mutagenic DNA repair through distinct phosphoprotein interactions

The DNA damage response (DDR) protein 53BP1 protects DNA ends from excessive resection in G1, and thereby favors repair by non-homologous end joining (NHEJ) as opposed to homologous recombination (HR). During S phase, BRCA1 antagonizes 53BP1 to promote HR. The pro-NHEJ and anti-recombinase functions of 53BP1 are mediated in part by RIF1, the only known factor that requires 53BP1 phosphorylation for its recruitment to double strand breaks (DSBs). Here we show that a 53BP1 phospho-mutant 53BP1(8A), comprising alanine substitutions of the 8 most N-terminal S/TQ phosphorylation sites, mimics 53BP1 deficiency by restoring genome stability in BRCA1 deficient cells yet behaves like wild-type 53BP1 with respect to immunoglobulin class switch recombination (CSR). 53BP1(8A) recruits RIF1 but fails to recruit the DDR protein PTIP to DSBs, and disruption of PTIP phenocopies 53BP1(8A). We conclude that 53BP1 promotes productive CSR and suppresses mutagenic DNA repair through distinct phospho-dependent interactions with RIF1 and PTIP