title: Human DNA helicase B (HDHB) binds to replication protein A and facilitates cellular recovery from replication stress.
abstract: Maintenance of genomic stability in proliferating cells depends on a network of proteins that coordinate chromosomal replication with DNA damage responses. Human DNA helicase B (HELB or HDHB) has been implicated in chromosomal replication, but its role in this coordinated network remains undefined. Here we report that cellular exposure to UV irradiation, camptothecin, or hydroxyurea induces accumulation of HDHB on chromatin in a dose- and time-dependent manner, preferentially in S phase cells. Replication stress-induced recruitment of HDHB to chromatin is independent of checkpoint signaling but correlates with the level of replication protein A (RPA) recruited to chromatin. We show using purified proteins that HDHB physically interacts with the N-terminal domain of the RPA 70-kDa subunit (RPA70N). NMR spectroscopy and site-directed mutagenesis reveal that HDHB docks on the same RPA70N surface that recruits S phase checkpoint signaling proteins to chromatin. Consistent with this pattern of recruitment, cells depleted of HDHB display reduced recovery from replication stress.
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235-1634, USA.
authors.forename: Gulfem Dilek
authors.initials: GD
authors.lastname: Guler
authors.forename: Hanjian
authors.initials: H
authors.lastname: Liu
authors.forename: Sivaraja
authors.initials: S
authors.lastname: Vaithiyalingam
authors.forename: Diana R
authors.initials: DR
authors.lastname: Arnett
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Chazin
authors.forename: Ellen
authors.initials: E
authors.lastname: Fanning
mesh_terms: D000595:Amino Acid Sequence; D002875:Chromosomes / Q000502:physiology; D004249:DNA Damage / Q000502:physiology*; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D012516:Osteosarcoma; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs / Q000502:physiology; D051716:Replication Protein A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D059807:S Phase Cell Cycle Checkpoints / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D051716:Replication Protein A; C484263:HELB protein, human; D004265:DNA Helicases