Proteins are synthesized as nacent polypeptide chains by the ribosome and must attain their correct three-dimensional shape to perform their specific biological function within the cell. The protein spatial arrangement is meticulously maintained during its functional life time, but after completing its biological task it is then degraded in a timely and efficient manner.
The mammalian cell comprises many thousands of diverse proteins that drive cellular activity all of which must be carefully controlled. A well-balanced proteome, also known as protein homeostasis, requires the coordinated action of a network of molecular chaperones, proteolytic and degradation machineries, together with their regulators, to ensure successful cell function and survival.
Protein homeostasis can be affected by external and endogenous stresses that may upset the balance leading to accumulation of misfolded protein which is toxic for the cell. Therefore, understanding how molecular chaperones and other proteostasis systems operate is of fundamental medical importance, as a failure to maintain protein homeostasis is associated with many diseases including cancer and degenerative disorders.