scholarly journals Corrigendum to “Synergistic Effects of Toxic Elements on Heat Shock Proteins”

2015 ◽  
Vol 2015 ◽  
pp. 1-1 ◽  
Author(s):  
Khalid Mahmood ◽  
Saima Jadoon ◽  
Qaisar Mahmood ◽  
Muhammad Irshad ◽  
Jamshaid Hussain
2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Khalid Mahmood ◽  
Saima Jadoon ◽  
Qaisar Mahmood ◽  
Muhammad Irshad ◽  
Jamshaid Hussain

Heat shock proteins show remarkable variations in their expression levels under a variety of toxic conditions. A research span expanded over five decades has revealed their molecular characterization, gene regulation, expression patterns, vast similarity in diverse groups, and broad range of functional capabilities. Their functions include protection and tolerance against cytotoxic conditions through their molecular chaperoning activity, maintaining cytoskeleton stability, and assisting in cell signaling. However, their role as biomarkers for monitoring the environmental risk assessment is controversial due to a number of conflicting, validating, and nonvalidating reports. The current knowledge regarding the interpretation of HSPs expression levels has been discussed in the present review. The candidature of heat shock proteins as biomarkers of toxicity is thus far unreliable due to synergistic effects of toxicants and other environmental factors. The adoption of heat shock proteins as “suit of biomarkers in a set of organisms” requires further investigation.


1998 ◽  
Vol 18 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Do Hee Lee ◽  
Alfred L. Goldberg

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.


1990 ◽  
Vol 80 (2) ◽  
pp. 301-306
Author(s):  
Tiina Vahala ◽  
Tage Eriksson ◽  
Peter Engstrom

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