title: The nucleosome binding protein HMGN1 interacts with PCNA and facilitates its binding to chromatin.
abstract: Proliferating cell nuclear antigen (PCNA) is a ubiquitous protein that interacts with multiple partners and regulates nuclear activities, including chromatin assembly, histone modifications, replication, and DNA damage repair. The role of specific partners in regulating PCNA activities is not fully understood. Here we identify the nucleosome binding protein HMGN1 as a new PCNA-interacting protein that enhances the binding of PCNA to chromatin but not to purified DNA. Two tetrapeptides in the conservative domain of HMGN1 contain amino acids necessary for the binding of HMGN1 to PCNA. Deletion of both tetrapeptides abolishes the HMGN1-PCNA interaction. PCNA preferentially binds to the linker DNA adjacent to an HMGN-containing nucleosome. In living cells, loss of HMGN1 decreases the rate of PCNA recruitment to damaged DNA sites. Our study identifies a new factor that facilitates the interaction of PCNA with chromatin and provides insights into mechanisms whereby nucleosome binding architectural proteins affect the cellular phenotype.
authors.affiliation: Protein Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, USA.
authors.forename: Yuri V
authors.initials: YV
authors.lastname: Postnikov
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kurahashi
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Michael
authors.initials: M
authors.lastname: Bustin
mesh_terms: D000818:Animals; D001665:Binding Sites; D002461:Cell Line, Transformed; D002843:Chromatin / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000378:metabolism; D024241:HMGN1 Protein / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009707:Nucleosomes / Q000378:metabolism; D009842:Oligopeptides; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D002843:Chromatin; D024241:HMGN1 Protein; D009707:Nucleosomes; D009842:Oligopeptides; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA