Proliferating cell nuclear antigen (PCNA) may function as a double homotrimer complex in the mammalian cell.
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.
Naryzhny
Stanislav N
SN
Department of Research, Northeastern Ontario Regional Cancer Centre, Sudbury, Ontario P3E 5J1, Canada.
Zhao
Helen
H
Lee
Hoyun
H
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
D002843:Chromatin; D046911:Macromolecular Substances; D010455:Peptides; D018809:Proliferating Cell Nuclear Antigen; D011993:Recombinant Fusion Proteins; D004247:DNA; D001120:Arginine; D008239:Lysine