Bacteria are unicellular organisms and inhabit numerous environmental conditions on earth. Therefore, bacteria must immediately detect environmental cues and respond appropriately to survive. In this context, proteins are key molecules in all living organisms, including bacteria. Protein synthesis begins in the ribosome. Synthesized polypeptides are folded spontaneously into their native structures but in some cases do not due to the organization of complex subunits. In addition, most proteins are often misfolded or denatured by various environmental changes, such as heat, low or high pH, osmotic shock, organic solvent, etc.

Cells thus possess sophisticated maintenance systems for protein folding and integrity, called molecular chaperones, which are critical factors for protein homeostasis. Chaperones aid the protein folding process by accelerating proper folding and preventing protein misfolding and aggregation. Notably, the role of chaperones is essential under stressed conditions. Diverse chaperones respond to specific stimuli through unique regulatory mechanisms for chaperon action. These stress-responsive chaperones prevent stress-induced protein aggregation and resolve protein aggregation.

Various experimental techniques and in vivo and in vitro tools have been developed to understand the role and detailed molecular mechanisms of chaperones. In this collection, we aim to share state-of-the-art methods widely used to investigate the function of bacterial chaperones in vitro and in vivo.