Protein Trafficking Diseases: Small Molecule Approaches

Many diseases are caused by defects in protein trafficking. Protein trafficking diseases occur when a mutant protein is recognized by the endoplasmic reticulum (ER) quality control system (ERQC), retained in the ER, and degraded in the cytosol by the proteasome rather than being trafficked to its correct site of action. Among these diseases are cystic fibrosis, lysosomal storage diseases (Fabry, Gaucher, and Tay-Sachs), nephrogenic diabetes insipidus, oculocutaneous albinism, protein C deficiency, and many others. A characteristic of many of these diseases is that the mutant protein remains functional, but it cannot escape the stringent ER quality-control machinery, and it is retained in the ER. This characteristic suggests that pharmacological interventions that promote the correct folding of the mutant protein would enable its escape from the ER and ameliorate the symptoms of the disease. In this review, we focus on specific examples of protein trafficking diseases in pharmacological or chemical chaperones have been shown to rescue trafficking of the mutant protein.