title: Deregulated Ras signaling compromises DNA damage checkpoint recovery in S. cerevisiae.
abstract: The DNA damage checkpoint maintains genome stability by arresting the cell cycle and promoting DNA repair under genotoxic stress. Cells must downregulate the checkpoint signaling pathways in order to resume cell division after completing DNA repair. While the mechanisms of checkpoint activation have been well-characterized, the process of checkpoint recovery, and the signals regulating it, has only recently been investigated. We have identified a new role for the Ras signaling pathway as a regulator of DNA damage checkpoint recovery. Here we report that in budding yeast, deletion of the IRA1 and IRA2 genes encoding negative regulators of Ras prevents cellular recovery from a DNA damage induced arrest. The checkpoint kinase Rad53 is dephosphorylated in an IRA-deficient strain, indicating that recovery failure is not caused by constitutive checkpoint pathway activation. The ira1Δ ira2Δ recovery defect requires the checkpoint kinase Chk1 and the cAMP-dependent protein kinase (PKA) catalytic subunit Tpk2. Furthermore, PKA phosphorylation sites on the anaphase promoting complex specificity factor Cdc20 are required for the recovery defect, indicating a link between the recovery defect and PKA regulation of mitosis. This work identifies a new signaling pathway that can regulate DNA damage checkpoint recovery and implicates the Ras signaling pathway as an important regulator of mitotic events.
authors: Department of Pharmacology and Toxicology, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, NH, USA.
authors: Matthew D
authors: MD
authors: Wood
authors: Yolanda
authors: Y
authors: Sanchez
mesh_terms: D020134:Catalytic Domain; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D008938:Mitosis; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D018631:ras Proteins / Q000378:metabolism*
chemical_list: C577495:CDC20 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; C065725:IRA1 protein, S cerevisiae; C064960:IRA2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; C457179:TPK2 protein, S cerevisiae; C067022:RAD53 protein, S cerevisiae; D018631:ras Proteins