The protein encoded by this gene is highly similar to S. cerevisiae DNA damage repair protein Rad18. Yeast Rad18 functions through interaction with Rad6, which is a ubiquitin-conjugating enzyme required for post-replication repair of damaged DNA. Similar to its yeast counterpart, this protein is able to interact with the human homolog of yeast Rad6 protein through a conserved ring finger motif. Mutation of this motif results in defective replication of UV-damaged DNA and hypersensitivity to multiple mutagens.[7]
RAD18 is an E3 ubiquitin ligase that enables movement of ubiquitin from a ubiquitin carrier to another protein (the substrate). One activity of RAD18 is to prevent replication fork collapse by promoting DNA translesion synthesis and template switching.[9] RAD18 is also involved in directing repair of DNA double-strand breaks by homologous recombination in post replicative chromatin.[9] RAD18 appears to promote homologous recombinational repair by recruiting the SMC5,SMC6 (SMC5/6) complex to the DNA breaks.[9]
