title: Rfa2 is specifically dephosphorylated by Pph3 in Candida albicans.
abstract: Rfa2 is a ssDNA (single-stranded DNA)-binding protein that plays an important role in DNA replication, recombination and repair. Rfa2 is regulated by phosphorylation, which alters its protein-protein interaction and protein-DNA interaction. In the present study, we found that the Pph3-Psy2 phosphatase complex is responsible for Rfa2 dephosphorylation both during normal G1-phase and under DNA replication stress in Candida albicans. Phosphorylated Rfa2 extracted from pph3Δ or psy2Δ G1 cells exhibited diminished binding affinity to dsDNA (double-stranded DNA) but not to ssDNA. We also discovered that Cdc28 (cell division cycle 28) and Mec1 are responsible for Rfa2 phosphorylation in G1-phase and under DNA replication stress respectively. Moreover, MS revealed that the domain of Rfa2 that was phosphorylated in G1-phase differed from that phosphorylated under the stress conditions. The results of the present study imply that differential phosphorylation plays a crucial role in RPA (replication protein A) regulation.
authors.affiliation: Key Laboratory of Cell Proliferation and Regulation Biology, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Gao
authors.forename: Ada Hang-Heng
authors.initials: AH
authors.lastname: Wong
authors.forename: Kangdi
authors.initials: K
authors.lastname: Hu
authors.forename: Wanjie
authors.initials: W
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.forename: Jianli
authors.initials: J
authors.lastname: Sang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002176:Candida albicans / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase; D005800:Genes, Fungal; D006918:Hydroxyurea / Q000494:pharmacology; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D051716:Replication Protein A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D046912:Multiprotein Complexes; D051716:Replication Protein A; D010749:Phosphoprotein Phosphatases; D006918:Hydroxyurea