21801845
not annotated - annotated - LINNAEUS only
The transcriptional response of Saccharomyces cerevisiae to proapoptotic concentrations of Pichia membranifaciens killer toxin.
PMKT (Pichia membranifaciens killer toxin) reportedly has antimicrobial activity against yeasts and filamentous fungi. In previous research we posited that high PMKT concentrations pose a serious challenge for cell survival by disrupting plasma membrane electrochemical gradients, inducing a transcriptional response similar to that of certain stimuli such as hyperosmotic shock. This response was related to the HOG-pathway with Hog1p phosphorylation and a transitional increase in intracellular glycerol accumulation. Such a response was consistent with the notion that the effect induced by high PMKT concentrations lies in an alteration to the ionic homeostasis of the sensitive cell. By contrast, the evidence presented here shows that low PMKT doses lead to a cell death process in Saccharomyces cerevisiae accompanied by cytological and biochemical indicators of apoptotic programmed cell death, namely, the production of reactive oxygen species, DNA strand breaks, metacaspase activation and cytochrome c release. Furthermore, dying cells progressed from an apoptotic state to a secondary necrotic state, and the rate at which this change occurred was proportional to the intensity of the stimulus. We have explored the global gene expression response of S. cerevisiae during that stimulus. The results obtained from DNA microarrays indicate that genes related with an oxidative stress response were induced in response to proapoptotic concentrations of PMKT, showing that the coordinated transcriptional response is not coincident with that obtained when ionophoric concentrations of PMKT are used. By contrast, cwp2Delta mutants showed no signs of apoptosis, indicating that the initial steps of the killer mechanism coincide when proapoptotic (low) or ionophoric (high) PMKT concentrations are used. Additionally, low dosages of PMKT promoted Hog1p phosphorylation and glycerol accumulation.
Ann file
T1 Species 32 56 Saccharomyces cerevisiae
N1 Reference T1 Taxonomy:4932
T2 Species 91 113 Pichia membranifaciens
N2 Reference T2 Taxonomy:4926
T3 Species 136 158 Pichia membranifaciens
N3 Reference T3 Taxonomy:4926
T4 Out-of-scope 219 225 yeasts
T5 Species 918 942 Saccharomyces cerevisiae
N5 Reference T5 Taxonomy:4932
T6 Species 1393 1406 S. cerevisiae
N6 Reference T6 Taxonomy:4932
N4 Reference T4 Taxonomy:147537 Saccharomycotina