Thermosensors in eubacteria: role and evolution.
J Biosci
;
2007 Apr; 32(3): 549-57
Article
in English
| IMSEAR
| ID: sea-111209
ABSTRACT
Temperature is an important physical stress factor sensed by bacteria and used to regulate gene expression. Three different macromolecules have been identified being able to sense temperature DNA, mRNA and proteins. Depending on the induction mechanism, two different pathways have to be distinguished, namely the heat shock response and the high temperature response. While the heat shock response is induced by temperature increments and is transient, the high temperature response needs a specific temperature to become induced and proceeds as long as cells are exposed to that temperature. The heat shock response is induced by denatured proteins and aimed to prevent formation of protein aggregates by refolding or degradation, and the high temperature response is mainly used by pathogenic bacteria to detect entry into a mammalian host followed by induction of their virulence genes. All known high temperature sensors are present in two alternative conformations depending on the temperature. Heat shock sensors are either molecular chaperones or proteases which keep either a positive transcriptional regulator inactive or a negative regulator active or do not attack the regulator, respectively, under physiological conditions. Denatured proteins either titrate the molecular chaperones or activate the protease. The evolution of the different temperature sensors is discussed.
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Bacteria
/
Body Temperature Regulation
/
Adaptation, Physiological
/
Biological Evolution
/
Hot Temperature
Type of study:
Prognostic study
Language:
English
Journal:
J Biosci
Year:
2007
Type:
Article
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