Roles and Regulation of the Heat Shock Proteins of the Major Human Pathogen Helicobacter pylori

The ability of pathogens to gauge the surroundings and modulate gene expression accordingly is a crucial feature for bacterial survival. In this respect, the heat-shock response, a universally conserved mechanism of protection, allows bacterial cells to adapt rapidly to hostile environmental conditions and to survive during stress. The major human pathogen Helicobacter pylori employs a collection of highly conserved heat-shock proteins (HSP) to preserve cellular proteins and to maintain their homeostasis, allowing the pathogen to adapt and survive in the hostile niche of the human stomach. Moreover, various evidences suggest that some chaperones of H. pylori may play also non-canonical roles, as for example in the interaction with the extracellular environment. In H. pylori, the regulation of HSP expression is orchestrated by two dedicated transcriptional repressors, named HspR and HrcA, as well as via a chaperones-dependent posttranscriptional feedback control acting on the activity of HspR and HrcA regulators themselves. This chapter briefly reviews our understanding of the roles and regulation of the most important HSP of H. pylori, which represent a crucial virulence factor for bacterial infection and persistence in the human host.