title: [Degradation of Cdc25A phosphatase in HeLa cells under normal and stress conditions].
abstract: Cdc25A phosphatase regulates cell cycle progression by removing the inhibitory phosphates from cyclin-dependent kinases. Activity of Cdc25A depends on its phosphorylation status. During normal cell cycle progression and after DNA damage phosphorylation by Chk1 (or Chk2) triggers Cdc25A degradation via ubiquitin-proteasome pathway. In this study we investigate the role of various phosphorylation sites (Ser123, Ser75, Ser17 and Ser115) in the regulation of Cdc25A stability. We have shown that only S75A mutation abrogates Cdc25A degradation both in normal and stress conditions. We also studied the influence of stable form of Cdc25A on checkpoint progression after DNA damage. We have found out that delay in DNA synthesis after UV and IR does not depend on Cdc25A activity. However, the presence of stable Cdc25A increases the number of mitotic cells after these stresses.
authors.forename: A R
authors.initials: AR
authors.lastname: Goloudina
authors.forename: N D
authors.initials: ND
authors.lastname: Aksenov
authors.forename: V A
authors.initials: VA
authors.lastname: Pospelov
mesh_terms: D000071877:Checkpoint Kinase 1; D004247:DNA / Q000096:biosynthesis; D004795:Enzyme Stability; D006367:HeLa Cells; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D012694:Serine / Q000737:chemistry / Q000235:genetics; D014466:Ultraviolet Rays; D020687:cdc25 Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D012694:Serine; D004247:DNA; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D020687:cdc25 Phosphatases