Activation of the protein kinase C1 pathway upon continuous heat stress in Saccharomyces cerevisiae is triggered by an intracellular increase in osmolarity due to trehalose accumulation.
This paper reports on physiological and molecular responses of Saccharomyces cerevisiae to heat stress conditions. We observed that within a very narrow range of culture temperatures, a shift from exponential growth to growth arrest and ultimately to cell death occurred. A detailed analysis was carried out of the accumulation of trehalose and the activation of the protein kinase C1 (PKC1) (cell integrity) pathway in both glucose- and ethanol-grown cells upon temperature upshifts within this narrow range of growth temperatures. It was observed that the PKC1 pathway was hardly activated in a tps1 mutant that is unable to accumulate any trehalose. Furthermore, it was observed that an increase of the extracellular osmolarity during a continuous heat stress prevented the activation of the pathway. The results of these analyses support our hypothesis that under heat stress conditions the activation of the PKC1 pathway is triggered by an increase in intracellular osmolarity, due to the accumulation of trehalose, rather than by the increase in temperature as such.
Mensonides
Femke I C
FI
Swammerdam Institute of Life Sciences, Department of Molecular Microbial Physiology, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
Brul
Stanley
S
Klis
Frans M
FM
Hellingwerf
Klaas J
KJ
Teixeira de Mattos
M Joost
MJ
D003470:Culture Media; D015966:Gene Expression Regulation, Fungal; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D009994:Osmolar Concentration; D011493:Protein Kinase C / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D013696:Temperature; D014199:Trehalose / Q000378:metabolism*
D003470:Culture Media; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D011493:Protein Kinase C