Deletion of yeast TPK1 reduces the efficiency of non-homologous end joining DNA repair.

Non-homologous end joining (NHEJ) is a highly conserved mechanism of DNA double-stranded break (DSB) repair. Here we utilize a computational protein-protein interaction method to identify human PRKACB as a potential candidate interacting with NHEJ proteins. We show that the deletion of its yeast homolog, TPK1 that codes for the protein kinase A catalytic subunit reduces the efficiency of NHEJ repair of breaks with overhangs and blunt ends in plasmid-based repair assays. Additionally, tpk1Δ mutants showed defects in the repair of chromosomal breaks induced by HO-site specific endonuclease. Our double deletion mutant analyses suggest that TPK1 and YKU80, a key player in NHEJ could function in parallel pathways. Altogether, here we report a novel involvement for TPK1 in NHEJ.