title: Proliferating cell nuclear antigen (PCNA) may function as a double homotrimer complex in the mammalian cell.
abstract: The diverse function of proliferating cell nuclear antigen (PCNA) may be regulated by interactions with different protein partners. Interestingly, the binding sites for all known PCNA-associating proteins are on the outer surface or the C termini ("front") sides of the PCNA trimer. Using cell extracts and purified human PCNA protein, we show here that two PCNA homotrimers form a back-to-back doublet. Mutation analysis suggests that the Arg-5 and Lys-110 residues on the PCNA back side are the contact points of the two homotrimers in the doublet. Furthermore, short synthetic peptides encompassing either Arg-5 or Lys-110 inhibit double trimer formation. We also found that a PCNA double trimer, but not a homotrimer alone, can simultaneously accommodate chromatin assembly factor-1 and polymerase delta. Together, our data supports a model that chromatin remodeling by chromatin assembly factor-1 (and, possibly, many other cellular activities) are tightly coupled with DNA replication (and repair) through a PCNA double trimer complex.
authors.affiliation: Department of Research, Northeastern Ontario Regional Cancer Centre, Sudbury, Ontario P3E 5J1, Canada.
authors.forename: Stanislav N
authors.initials: SN
authors.lastname: Naryzhny
authors.forename: Helen
authors.initials: H
authors.lastname: Zhao
authors.forename: Hoyun
authors.initials: H
authors.lastname: Lee
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism; D016466:CHO Cells; D002843:Chromatin / Q000378:metabolism; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D006801:Humans; D008239:Lysine / Q000378:metabolism; D046911:Macromolecular Substances; D008958:Models, Molecular; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D002843:Chromatin; D046911:Macromolecular Substances; D010455:Peptides; D018809:Proliferating Cell Nuclear Antigen; D011993:Recombinant Fusion Proteins; D004247:DNA; D001120:Arginine; D008239:Lysine