Individual cells of the yeast Saccharomyces cerevisiae have a limited replicative life-span. The role of the genes RAS1 and RAS2 in yeast longevity was examined. Over-expression of RAS2 led to a 30% increase in the life-span on average and postponed the senescence-related increase in generation time seen during yeast aging. No life-span extension was obtained by overexpression of RAS1. However, deletion of RAS1 prolonged the life-span. These results suggest that RAS1 and RAS2 play reciprocal roles in determining yeast longevity. RAS1 and RAS2 mRNA and protein levels declined with replicative age, suggesting a diminishing impact on yeast longevity. The major known pathway through which Ras proteins function in yeast involves stimulation of adenylate cyclase. No evidence for a life-span-extending effect of elevated intracellular cAMP was found. Indeed, high intracellular cAMP was associated with curtailed life-span. A similar decrease in life-span was found on disruption of BCY1, which codes for the regulatory subunit of protein kinase A, the downstream target of cAMP. Importantly, overexpression of an effector domain mutant of RAS2, defective in stimulation of adenylate cyclase, prolonged life-span to the same extent as the wild-type gene, suggesting that the cAMP pathway is neither sufficient nor necessary for increased longevity.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|