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 structurs 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. 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. The C-terminal domain binds EP300. Can bind simultaneously to both PCNA and EP300. Interacts with DDX11. Belongs to the XPG/RAD2 endonuclease family. FEN1 subfamily. Note: This description may include information from UniProtKB.
Protein type: Ribonuclease; DNA binding protein; EC 3.1.-.-; Deoxyribonuclease; DNA repair, damage; Nucleolus
Molecular Function: 5'-3' exonuclease activity; protein binding; DNA binding; 5'-flap endonuclease activity; manganese ion binding; endonuclease activity; exonuclease activity; double-stranded DNA binding; magnesium ion binding; damaged DNA binding; ribonuclease H activity; double-stranded DNA specific exodeoxyribonuclease activity
Biological Process: DNA replication, removal of RNA primer; phosphoinositide-mediated signaling; DNA strand elongation during DNA replication; DNA repair; DNA catabolic process, endonucleolytic; memory; telomere maintenance via semi-conservative replication; UV protection; base-excision repair; double-strand break repair; telomere maintenance via recombination; mitotic cell cycle; DNA replication; DNA catabolic process, exonucleolytic; telomere maintenance
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.