Protein folding is the process whereby newly synthesised linear polypeptide chains fold into the well-defined 3-dimensional shape of the functional protein. In many cases, molecular chaperones assist in correct protein folding by preventing the newly synthesised protein from aggregating into non-functional structures. A variety of diseases result from misfolded proteins; loss-of-function diseases are often caused by a point mutation in the sequence of the protein which disturbs the normal balance between protein folding and clearance. There has been recent interest in the development of ‘pharmacological chaperones’ which are small molecules that stabilise the correct protein fold.
A recent study describes two small molecules, celastrol and MG-132, that are able to enhance mutant protein folding and function in cell culture experiments. These compounds acted synergistically with known pharmacological chaperones and increased the activity of mutant proteins to 50% of wild-type activity. This study provides encouragement for the concept of developing regulators of proteostatis for the treatment of a range of loss-of-function diseases.