Pathways of chaperone-mediated protein folding in the cytosol

Cells are faced with the task of folding thousands of different polypeptides into a wide range of conformations. For many proteins, the folding process requires the action of molecular chaperones. In the cytosol of prokaryotic and eukaryotic cells, molecular chaperones of different structural classes form a network of pathways that can handle substrate polypeptides from the point of initial synthesis on ribosomes to the final stages of folding.