Chaperones

Chaperones are proteins that assist in the folding of other proteins. They prevent misfolding and aggregation, and also help to target newly synthesized proteins to the correct cellular location. Chaperones are important for protein homeostasis, and malfunction of chaperone proteins has been implicated in a number of diseases.

Molecular chaperones are classified into several families based on their structure and function. The best-known family of chaperones is the Hsp70 family. Hsp70s are ATP-dependent enzymes that bind to unfolding or misfolded proteins and prevent them from aggregating. Other families of chaperones include the small heat shock proteins (sHSPs), which assist in refolding of denatured proteins, and the cytosolic chaperonins (CCPs), which facilitate protein folding in an ATP-dependent manner.

In addition to assisting in protein folding, chaperones also play important roles in many other cellular processes such as cell cycle progression, signal transduction, vesicular trafficking, and autophagy. For example, sHSPs have been shown to be involved in cancer cell metastasis by regulating actin remodeling. In yeast, certain CCPs are required for efficient mating between haploid cells. And mammalian CCPs have been implicated in neurodegenerative diseases such as Alzheimer’s disease and Huntington’s disease.

Recent advances in our understanding of chaperone function have come from studies using high-throughput methods such as proteomics and RNAseq. These techniques have allowed us to identify hundreds of new chaperone genes, many of which remain uncharacterized. Furthermore, these techniques have helped us to understand how different types of stress affect the proteome and how cells respond by upregulating specific sets of chaperone genes.