title: A non-death role of the yeast metacaspase: Yca1p alters cell cycle dynamics.
abstract: Caspase proteases are a conserved protein family predominantly known for engaging and executing apoptotic cell death. Nevertheless, in higher eukaryotes, caspases also influence a variety of cell behaviors including differentiation, proliferation and growth control. S. cerevisiae expresses a primordial caspase, yca1, and exhibits apoptosis-like death under certain stresses; however, the benefit of a dedicated death program to single cell organisms is controversial. In the absence of a clear rationale to justify the evolutionary retention of a death only pathway, we hypothesize that yca1 also influences non-apoptotic events. We report that genetic ablation and/or catalytic inactivation of Yca1p leads to a longer G1/S transition accompanied by slower growth in fermentation conditions. Downregulation of Yca1p proteolytic activity also results in failure to arrest during nocodazole treatment, indicating that Yca1p participates in the G2/M mitotic checkpoint. 20s proteasome activity and ROS staining of the Delta yca1 strain is indistinguishable from its isogenic control suggesting that putative regulation of the oxidative stress response by Yca1p does not instigate the cell cycle phenotype. Our results demonstrate multiple non-death roles for yca1 in the cell cycle.
authors.affiliation: Regenerative Medicine Program, Ottawa Health Research Institute, Sprott Centre for Stem Cell Research, Ottawa, Canada.
authors.forename: Robin E C
authors.initials: RE
authors.lastname: Lee
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Puente
authors.forename: Mads
authors.initials: M
authors.lastname: Kaern
authors.forename: Lynn A
authors.initials: LA
authors.lastname: Megeney
mesh_terms: D019943:Amino Acid Substitution; D020169:Caspases / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D003545:Cysteine / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase; D015966:Gene Expression Regulation, Fungal; D015739:Nocodazole / Q000494:pharmacology; D010641:Phenotype; D011401:Promoter Regions, Genetic; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D020169:Caspases; C456272:MCA1 protein, S cerevisiae; D003545:Cysteine; D015739:Nocodazole