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The role of proteosome-mediated proteolysis in modulating potentially harmful transcription factor activity in Saccharomyces cerevisiae.

Bonzanni N, Zhang N, Oliver SG, Fisher J - Bioinformatics (2011)

Bottom Line: Particularly, controlling the abundance of proteins that may have detrimental effects on cell growth is crucial for rapid recovery from stress-induced quiescence.Additional bioinformatics analyses show that potentially toxic transcriptional regulators have a significantly lower protein half-life, a higher fraction of unstructured regions and more potential PEST motifs than the non-detrimental ones.Our combined results suggest that proteasome-mediated proteolysis of potentially toxic transcription factors tightly modulates the stress response in yeast. jasmin.fisher@microsoft.com

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Bioinformatics VU, VU University Amsterdam, De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands.

ABSTRACT

Motivation: The appropriate modulation of the stress response to variable environmental conditions is necessary to maintain sustained viability in Saccharomyces cerevisiae. Particularly, controlling the abundance of proteins that may have detrimental effects on cell growth is crucial for rapid recovery from stress-induced quiescence.

Results: Prompted by qualitative modeling of the nutrient starvation response in yeast, we investigated in vivo the effect of proteolysis after nutrient starvation showing that, for the Gis1 transcription factor at least, proteasome-mediated control is crucial for a rapid return to growth. Additional bioinformatics analyses show that potentially toxic transcriptional regulators have a significantly lower protein half-life, a higher fraction of unstructured regions and more potential PEST motifs than the non-detrimental ones. Furthermore, inhibiting proteasome activity tends to increase the expression of genes induced during the Environmental Stress Response more than those in the rest of the genome. Our combined results suggest that proteasome-mediated proteolysis of potentially toxic transcription factors tightly modulates the stress response in yeast.

Contact: jasmin.fisher@microsoft.com

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Related in: MedlinePlus

Cells over-expressing Gis1 at starvation have a longer lag phase than wild-type cells. Cells bearing either pCM190-GIS1 or the empty vector, pCM190, were grown (in the presence of doxycycline) for 24 h to glucose starvation, at which point >90% of cells have no buds. Aliquots (2 ml) of cell cultures were washed twice in SMM medium without glucose or doxycycline, resuspended in 40 ml of SMM, and incubated for 36 h to allow GIS1 expression. At this point, glucose (2%) and doxycycline (20μg/ml) were added to the cultures. Growth was monitored as OD600nm.
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Figure 3: Cells over-expressing Gis1 at starvation have a longer lag phase than wild-type cells. Cells bearing either pCM190-GIS1 or the empty vector, pCM190, were grown (in the presence of doxycycline) for 24 h to glucose starvation, at which point >90% of cells have no buds. Aliquots (2 ml) of cell cultures were washed twice in SMM medium without glucose or doxycycline, resuspended in 40 ml of SMM, and incubated for 36 h to allow GIS1 expression. At this point, glucose (2%) and doxycycline (20μg/ml) were added to the cultures. Growth was monitored as OD600nm.

Mentions: Wild-type yeast cells were transformed with plasmid pCM190 or the same plasmid bearing the GIS1 gene under the control of the repressible promoter, tetO. Cells were grown in the presence of doxycycline to early stationary phase, washed and resuspended in medium with no glucose or doxycycline for 36 h. There is no difference in viability between cells bearing the empty plasmid and those carrying the tetO-GIS1 plasmid (data not shown). Glucose and doxycycline were added to allow cells to resume growth. As shown in Figure 3, cells harboring the tetO-GIS1 plasmid display a 15% longer lag phase than those bearing the empty plasmid, suggesting that GIS1 overexpression during the transition to quiescence, delays the subsequent resumption of exponential growth on re-addition of nutrients. These data indicate that proteolytic degradation of Gis1 by the proteasome may provide cells with an important evolutionary advantage, since periods of nutrient availability and starvation are commonly experienced by microorganisms (Gasch and Werner-Washburne, 2002).Fig. 3.


The role of proteosome-mediated proteolysis in modulating potentially harmful transcription factor activity in Saccharomyces cerevisiae.

Bonzanni N, Zhang N, Oliver SG, Fisher J - Bioinformatics (2011)

Cells over-expressing Gis1 at starvation have a longer lag phase than wild-type cells. Cells bearing either pCM190-GIS1 or the empty vector, pCM190, were grown (in the presence of doxycycline) for 24 h to glucose starvation, at which point >90% of cells have no buds. Aliquots (2 ml) of cell cultures were washed twice in SMM medium without glucose or doxycycline, resuspended in 40 ml of SMM, and incubated for 36 h to allow GIS1 expression. At this point, glucose (2%) and doxycycline (20μg/ml) were added to the cultures. Growth was monitored as OD600nm.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117362&req=5

Figure 3: Cells over-expressing Gis1 at starvation have a longer lag phase than wild-type cells. Cells bearing either pCM190-GIS1 or the empty vector, pCM190, were grown (in the presence of doxycycline) for 24 h to glucose starvation, at which point >90% of cells have no buds. Aliquots (2 ml) of cell cultures were washed twice in SMM medium without glucose or doxycycline, resuspended in 40 ml of SMM, and incubated for 36 h to allow GIS1 expression. At this point, glucose (2%) and doxycycline (20μg/ml) were added to the cultures. Growth was monitored as OD600nm.
Mentions: Wild-type yeast cells were transformed with plasmid pCM190 or the same plasmid bearing the GIS1 gene under the control of the repressible promoter, tetO. Cells were grown in the presence of doxycycline to early stationary phase, washed and resuspended in medium with no glucose or doxycycline for 36 h. There is no difference in viability between cells bearing the empty plasmid and those carrying the tetO-GIS1 plasmid (data not shown). Glucose and doxycycline were added to allow cells to resume growth. As shown in Figure 3, cells harboring the tetO-GIS1 plasmid display a 15% longer lag phase than those bearing the empty plasmid, suggesting that GIS1 overexpression during the transition to quiescence, delays the subsequent resumption of exponential growth on re-addition of nutrients. These data indicate that proteolytic degradation of Gis1 by the proteasome may provide cells with an important evolutionary advantage, since periods of nutrient availability and starvation are commonly experienced by microorganisms (Gasch and Werner-Washburne, 2002).Fig. 3.

Bottom Line: Particularly, controlling the abundance of proteins that may have detrimental effects on cell growth is crucial for rapid recovery from stress-induced quiescence.Additional bioinformatics analyses show that potentially toxic transcriptional regulators have a significantly lower protein half-life, a higher fraction of unstructured regions and more potential PEST motifs than the non-detrimental ones.Our combined results suggest that proteasome-mediated proteolysis of potentially toxic transcription factors tightly modulates the stress response in yeast. jasmin.fisher@microsoft.com

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Bioinformatics VU, VU University Amsterdam, De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands.

ABSTRACT

Motivation: The appropriate modulation of the stress response to variable environmental conditions is necessary to maintain sustained viability in Saccharomyces cerevisiae. Particularly, controlling the abundance of proteins that may have detrimental effects on cell growth is crucial for rapid recovery from stress-induced quiescence.

Results: Prompted by qualitative modeling of the nutrient starvation response in yeast, we investigated in vivo the effect of proteolysis after nutrient starvation showing that, for the Gis1 transcription factor at least, proteasome-mediated control is crucial for a rapid return to growth. Additional bioinformatics analyses show that potentially toxic transcriptional regulators have a significantly lower protein half-life, a higher fraction of unstructured regions and more potential PEST motifs than the non-detrimental ones. Furthermore, inhibiting proteasome activity tends to increase the expression of genes induced during the Environmental Stress Response more than those in the rest of the genome. Our combined results suggest that proteasome-mediated proteolysis of potentially toxic transcription factors tightly modulates the stress response in yeast.

Contact: jasmin.fisher@microsoft.com

Show MeSH
Related in: MedlinePlus