The function of RNF169 (ring finger protein 169, ENSG00000166439) is as follows. Probable E3 ubiquitin-protein ligase that acts as a regulator of double-strand breaks (DSBs) repair following DNA damage. Functions in a non-canonical fashion to harness RNF168-mediated protein recruitment to DSB-containing chromatin, thereby contributing to regulation of DSB repair pathway utilization (PubMed:22492721, PubMed:30773093). Once recruited to DSB repair sites by recognizing and binding ubiquitin catalyzed by RNF168, competes with TP53BP1 and BRCA1 for association with RNF168-modified chromatin, thereby favouring homologous recombination repair (HRR) and single-strand annealing (SSA) instead of non-homologous end joining (NHEJ) mediated by TP53BP1 (PubMed:30104380, PubMed:30773093). E3 ubiquitin-protein ligase activity is not required for regulation of DSBs repair. {ECO:0000269|PubMed:22492721, ECO:0000269|PubMed:22733822, ECO:0000269|PubMed:22742833, ECO:0000269|PubMed:30104380, ECO:0000269|PubMed:30773093}.