The heat shock response in bacteria involves:
Sudden increase in ambient temperature from 30 to 42 degrees Celsius and beyond causes widespread protein unfolding, misfolding and aggregation, exposing normally buried hydrophobic patches that drive non-native interactions and toxic oligomerization threatening proteome integrity. Bacterial heat shock response is orchestrated by alternative sigma factor sigma32 encoded by rpoH gene, whose expression is regulated at multiple levels including translation efficiency enhanced at high temperature via melting of inhibitory mRNA secondary structure and protein stability controlled by DnaK-DnaJ chaperone sequestration and FtsH proteolysis. When active, sigma32 directs core RNA polymerase to promoters of heat shock genes, massively upregulating molecular chaperones GroEL-GroES that provide ATP-dependent Anfinsen cage isolation for folding of 10 percent of proteome, DnaK-DnaJ-GrpE Hsp70 system that binds extended hydrophobic segments preventing aggregation and assisting refolding, ATP-dependent Clp proteases such as ClpP-ClpX and ClpB disaggregase that degrade irreparably damaged proteins, and Lon protease. This integrated network restores proteostasis, prevents inclusion body formation and permits survival. Increased ribosome synthesis would enhance growth not protection, decreased membrane fluidity would exacerbate stress, decreased ATP production reflects energy failure, so chaperone upregulation defines adaptive heat response signature conserved from bacteria to humans.
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 7: Heat Shock Response and Chaperone Upregulation.