biostudies-literatureVigasova DNCI NIH HHSWellcome TrustNIGMS NIH HHS5341-53https://www.ebi.ac.uk/biostudies/studies/S-EPMC3664818biostudies-literatureUnknown41(10)Non-homologous end-joining (NHEJ) repairs DNA double-strand breaks by tethering and ligating the two DNA ends. The mechanisms regulating NHEJ efficiency and interplay between its components are not fully understood. Here, we identify and characterize the SUMOylation of budding yeast Lif1 protein, which is required for the ligation step in NHEJ. We show that Lif1 SUMOylation occurs throughout the cell cycle and requires the Siz SUMO ligases. Single-strand DNA, but not double-strand DNA or the Lif1 binding partner Nej1, is inhibitory to Lif1 SUMOylation. We identify lysine 301 as the major conjugation site and demonstrate that its replacement with arginine completely abolishes Lif1 SUMOylation in vivo and in vitro. The lif1-K301R mutant cells exhibit increased levels of NHEJ repair compared Nucleic acids researchLif1 SUMOylation and its role in non-homologous end-joining.PMC3664818P30 CA008748R01 GM080670WT076476Nikulenkov FKrejci LVlasakova DAnrather DVigasova DSlezakova ZAltmannova VKolesar PGith RSarangi PZhao XChovanec MfalseLif1 SUMOylation and its role in non-homologous end-joining.Non-homologous end-joining (NHEJ) repairs DNA double-strand breaks by tethering and ligating the two DNA ends. The mechanisms regulating NHEJ efficiency and interplay between its components are not fully understood. Here, we identify and characterize the SUMOylation of budding yeast Lif1 protein, which is required for the ligation step in NHEJ. We show that Lif1 SUMOylation occurs throughout the cell cycle and requires the Siz SUMO ligases. Single-strand DNA, but not double-strand DNA or the Lif1 binding partner Nej1, is inhibitory to Lif1 SUMOylation. We identify lysine 301 as the major conjugation site and demonstrate that its replacement with arginine completely abolishes Lif1 SUMOylation in vivo and in vitro. The lif1-K301R mutant cells exhibit increased levels of NHEJ repair compared 2013-01-01T00:00:00Z2013 May2025-04-04T23:39:52.877Z2019-03-27T01:10:27ZS-EPMC36648182357175910.1093/nar/gkt236