Open AccessAn overview of heat-stress response regulation in Gram-negative bacteria considering Escherichia coli as a model organism
Author(s) -
Deborupa Paul,
Sanmitra Ghosh
Publication year - 2022
Publication title -
journal of experimental biology and agricultural sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.108
H-Index - 2
ISSN - 2320-8694
DOI - 10.18006/2022.10(1).190.200
Subject(s) - bacterial outer membrane , biology , sigma factor , heat shock protein , heat shock , microbiology and biotechnology , escherichia coli , hsp70 , organism , model organism , function (biology) , gene , cellular stress response , biochemistry , genetics , rna polymerase , fight or flight response
Response to heat stress (HSR) is a key stress response for endurance in Escherichia coli mediated by transcriptional factor σ-32. Even though there has been extensive investigation on the contribution of proteins and chaperones in retaining protein stability in cells under stress conditions, limited information is available regarding the dynamic nature of mechanisms regulating the activity of the highly conserved heat shock proteins (Hsps). Several gene expression-based studies suggest the pivotal role of Hsp70 (DnaK) in the regulation of the expression of heat shock genes (Hsg). Direct interaction of Hsp70 with σ-32 may regulate this function in E. coli. Recent studies revealed that localization of σ-32 to the membrane interior by SRP-dependent pathway enables them to function appropriately in their role as regulators. The contributions of different cellular components including cell membrane remain unknown. Other cellular components or σ-32 interfere with polypeptides which could play a crucial role in cell survival. Sigma factor monitors and preserves outer membrane integrity of E. coli by stimulating the genes regulating outer membrane proteins (OMPs) and lipopolysaccharide (LPS) assemblage as well as through expression of small RNAs to down-regulate surplus unassembled OMPs. σ-E activity is regulated by the rate at which its membrane-encompassing anti-sigma factor, RseA is degraded. Mutations in rseA are reported to constitutively increase the sigma (E) activity that is validated at both genetic and biochemical levels. In this review, the basic mechanism of heat stress regulation in gram-negative bacteria has been elaborated using E. coli as a model organism.