Component of the MMS22L-TONSL complex, a complex that promotes homologous recombination-mediated repair of double-strand breaks (DSBs) at stalled or collapsed replication forks (PubMed:21055983, PubMed:21055984, PubMed:21055985, PubMed:21113133, PubMed:26527279, PubMed:27338793, PubMed:27797818, PubMed:29478807, PubMed:30773278). The MMS22L-TONSL complex is required to maintain genome integrity during DNA replication (PubMed:21055983, PubMed:21055984, PubMed:21055985). It mediates the assembly of RAD51 filaments on single-stranded DNA (ssDNA): the MMS22L-TONSL complex is recruited to DSBs following histone replacement by histone chaperones and eviction of the replication protein A complex (RPA/RP-A) from DSBs (PubMed:21055983, PubMed:21055984, PubMed:21055985, PubMed:27797818, PubMed:29478807). Following recruitment to DSBs, the TONSL-MMS22L complex promotes recruitment of RAD51 filaments and subsequent homologous recombination (PubMed:27797818, PubMed:29478807). Within the complex, TONSL acts as a histone reader, which recognizes and binds newly synthesized histones following their replacement by histone chaperones (PubMed:27338793, PubMed:29478807). Specifically binds histone H4 lacking methylation at 'Lys-20' (H4K20me0) and histone H3.1 (PubMed:27338793). {ECO:0000269|PubMed:21055983, ECO:0000269|PubMed:21055984, ECO:0000269|PubMed:21055985, ECO:0000269|PubMed:21113133, ECO:0000269|PubMed:26527279, ECO:0000269|PubMed:27338793, ECO:0000269|PubMed:27797818, ECO:0000269|PubMed:29478807, ECO:0000269|PubMed:30773278}. This is the function of ENSG00000160949 (TONSL, tonsoku like, DNA repair protein).