Gene Product Description
UniProt ID: Q6TNU4
FUNCTION: Structure-specific nuclease with 5'-flap endonuclease and 5'- 3' exonuclease activities involved in DNA replication and repair. During DNA replication, cleaves the 5'-overhanging flap structure that is generated by displacement synthesis when DNA polymerase encounters the 5'-end of a downstream Okazaki fragment. It enters the flap from the 5'-end and then tracks to cleave the flap base, leaving a nick for ligation. Also involved in the long patch base excision repair (LP-BER) pathway, by cleaving within the apurinic/apyrimidinic (AP) site- terminated flap. Acts as a genome stabilization factor that prevents flaps from equilibrating into structures that lead to duplications and deletions. Also possesses 5'-3' exonuclease activity on nicked or gapped double-stranded DNA, and exhibits RNase H activity. Also involved in replication and repair of rDNA and in repairing mitochondrial DNA. {ECO:0000255|HAMAP-Rule:MF_03140}.
COFACTOR: Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-Rule:MF_03140}; Note=Binds 2 magnesium ions per subunit. They probably participate in the reaction catalyzed by the enzyme. May bind an additional third magnesium ion after substrate binding. {ECO:0000255|HAMAP- Rule:MF_03140};
SUBUNIT: Interacts with PCNA. Three molecules of fen1 bind to one PCNA trimer with each molecule binding to one PCNA monomer. PCNA stimulates the nuclease activity without altering cleavage specificity. {ECO:0000255|HAMAP-Rule:MF_03140}.
SUBCELLULAR LOCATION: Nucleus, nucleolus {ECO:0000255|HAMAP- Rule:MF_03140}. Nucleus, nucleoplasm {ECO:0000255|HAMAP-Rule:MF_03140}. Mitochondrion {ECO:0000255|HAMAP-Rule:MF_03140}. Note=Resides mostly in the nucleoli and relocalizes to the nucleoplasm upon DNA damage. {ECO:0000255|HAMAP-Rule:MF_03140}.
PTM: Phosphorylated. Phosphorylation upon DNA damage induces relocalization to the nuclear plasma. {ECO:0000255|HAMAP- Rule:MF_03140}.
SIMILARITY: Belongs to the XPG/RAD2 endonuclease family. FEN1 subfamily. {ECO:0000255|HAMAP-Rule:MF_03140}.
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