title: Human replication factor C stimulates flap endonuclease 1.
abstract: Flap endonuclease 1 (FEN1) is the enzyme responsible for specifically removing the flap structure produced during DNA replication, repair, and recombination. Here we report that the human replication factor C (RFC) complex stimulates the nuclease activity of human FEN1 in an ATP-independent manner. Although proliferating cell nuclear antigen is also known to stimulate FEN1, less RFC was required for comparable FEN1 stimulation. Kinetic analyses indicate that the mechanism by which RFC stimulates FEN1 is distinct from that by proliferating cell nuclear antigen. Heat-denatured RFC or its subunit retained, fully or partially, the ability to stimulate FEN1. Via systematic deletion analyses, we have defined three specific regions of RFC4 capable of stimulating FEN1. The region of RFC4 with the highest activity spans amino acids 170-194 and contains RFC box VII. Four amino acid residues (i.e. Tyr-182, Glu-188, Pro-189, and Ser-192) are especially important for FEN1 stimulatory activity. Thus, RFC, via several stimulatory motifs per molecule, potently activates FEN1. This function makes RFC a critical partner with FEN1 for the processing of eukaryotic Okazaki fragments.
authors.affiliation: Center for DNA Replication and Genome Instability, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea.
authors.forename: Il-Taeg
authors.initials: IT
authors.lastname: Cho
authors.forename: Do-Hyung
authors.initials: DH
authors.lastname: Kim
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kang
authors.forename: Chul-Hwan
authors.initials: CH
authors.lastname: Lee
authors.forename: Tamir
authors.initials: T
authors.lastname: Amangyelid
authors.forename: Tuan Anh
authors.initials: TA
authors.lastname: Nguyen
authors.forename: Jerard
authors.initials: J
authors.lastname: Hurwitz
authors.forename: Yeon-Soo
authors.initials: YS
authors.lastname: Seo
mesh_terms: D000595:Amino Acid Sequence; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D045585:Flap Endonucleases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D051818:Replication Protein C / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D045585:Flap Endonucleases; C468317:FEN1 protein, human; C468323:RAD27 protein, S cerevisiae; D051818:Replication Protein C