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Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance inSaccharomyces cerevisiae

Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer... Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance in Saccharomyces cerevisiae Do Hee Lee and Alfred L. Goldberg * Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115 Abstract An accumulation in cells of unfolded proteins is believed to be the common signal triggering the induction of heat shock proteins (hsps). Accordingly, in Saccharomyces cerevisiae , inhibition of protein breakdown at 30°C with the proteasome inhibitor MG132 caused a coordinate induction of many heat shock proteins within 1 to 2 h. Concomitantly, MG132, at concentrations that had little or no effect on growth rate, caused a dramatic increase in the cells’ resistance to very high temperature. The magnitude of this effect depended on the extent and duration of the inhibition of proteolysis. A similar induction of hsps and thermotolerance was seen with another proteasome inhibitor, clasto -lactacystin β-lactone, but not with an inhibitor of vacuolar proteases. Surprisingly, when the reversible inhibitor MG132 was removed, thermotolerance decreased rapidly, while synthesis of hsps continued to increase. In addition, exposure to MG132 and 37°C together had synergistic effects in promoting thermotolerance but did not increase hsp expression beyond that seen with either stimulus alone. Although thermotolerance did not correlate with hsp content, another thermoprotectant trehalose accumulated upon exposure of cells to MG132, and the cellular content of this disaccharide, unlike that of hsps, quickly decreased upon removal of MG132. Also, MG132 and 37°C had additive effects in causing trehalose accumulation. Thus, the resistance to heat induced by proteasome inhibitors is not just due to induction of hsps but also requires a short-lived metabolite, probably trehalose, which accumulates when proteolysis is reduced. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Molecular and Cellular Biology American Society For Microbiology

Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance inSaccharomyces cerevisiae

Molecular and Cellular Biology , Volume 18 (1): 30 – Jan 1, 1998

Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance inSaccharomyces cerevisiae

Molecular and Cellular Biology , Volume 18 (1): 30 – Jan 1, 1998

Abstract

Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance in Saccharomyces cerevisiae Do Hee Lee and Alfred L. Goldberg * Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115 Abstract An accumulation in cells of unfolded proteins is believed to be the common signal triggering the induction of heat shock proteins (hsps). Accordingly, in Saccharomyces cerevisiae , inhibition of protein breakdown at 30°C with the proteasome inhibitor MG132 caused a coordinate induction of many heat shock proteins within 1 to 2 h. Concomitantly, MG132, at concentrations that had little or no effect on growth rate, caused a dramatic increase in the cells’ resistance to very high temperature. The magnitude of this effect depended on the extent and duration of the inhibition of proteolysis. A similar induction of hsps and thermotolerance was seen with another proteasome inhibitor, clasto -lactacystin β-lactone, but not with an inhibitor of vacuolar proteases. Surprisingly, when the reversible inhibitor MG132 was removed, thermotolerance decreased rapidly, while synthesis of hsps continued to increase. In addition, exposure to MG132 and 37°C together had synergistic effects in promoting thermotolerance but did not increase hsp expression beyond that seen with either stimulus alone. Although thermotolerance did not correlate with hsp content, another thermoprotectant trehalose accumulated upon exposure of cells to MG132, and the cellular content of this disaccharide, unlike that of hsps, quickly decreased upon removal of MG132. Also, MG132 and 37°C had additive effects in causing trehalose accumulation. Thus, the resistance to heat induced by proteasome inhibitors is not just due to induction of hsps but also requires a short-lived metabolite, probably trehalose, which accumulates when proteolysis is reduced.

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Publisher
American Society For Microbiology
Copyright
Copyright © 1998 by the American society for Microbiology.
ISSN
0270-7306
eISSN
1098-5549
Publisher site
See Article on Publisher Site

Abstract

Proteasome Inhibitors Cause Induction of Heat Shock Proteins and Trehalose, Which Together Confer Thermotolerance in Saccharomyces cerevisiae Do Hee Lee and Alfred L. Goldberg * Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115 Abstract An accumulation in cells of unfolded proteins is believed to be the common signal triggering the induction of heat shock proteins (hsps). Accordingly, in Saccharomyces cerevisiae , inhibition of protein breakdown at 30°C with the proteasome inhibitor MG132 caused a coordinate induction of many heat shock proteins within 1 to 2 h. Concomitantly, MG132, at concentrations that had little or no effect on growth rate, caused a dramatic increase in the cells’ resistance to very high temperature. The magnitude of this effect depended on the extent and duration of the inhibition of proteolysis. A similar induction of hsps and thermotolerance was seen with another proteasome inhibitor, clasto -lactacystin β-lactone, but not with an inhibitor of vacuolar proteases. Surprisingly, when the reversible inhibitor MG132 was removed, thermotolerance decreased rapidly, while synthesis of hsps continued to increase. In addition, exposure to MG132 and 37°C together had synergistic effects in promoting thermotolerance but did not increase hsp expression beyond that seen with either stimulus alone. Although thermotolerance did not correlate with hsp content, another thermoprotectant trehalose accumulated upon exposure of cells to MG132, and the cellular content of this disaccharide, unlike that of hsps, quickly decreased upon removal of MG132. Also, MG132 and 37°C had additive effects in causing trehalose accumulation. Thus, the resistance to heat induced by proteasome inhibitors is not just due to induction of hsps but also requires a short-lived metabolite, probably trehalose, which accumulates when proteolysis is reduced.

Journal

Molecular and Cellular BiologyAmerican Society For Microbiology

Published: Jan 1, 1998

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