A new study shows that the protein CHIP can regulate the insulin receptor more efficiently alone than in a paired state. In cellular stress situations, CHIP usually appears as a homodimer—an association of two identical proteins—and primarily serves to degrade misfolded and defective proteins. CHIP thus cleans up the cell. To this end, CHIP collaborates with helper proteins to attach a chain of the small protein ubiquitin to misfolded proteins. The defective proteins are thus recognized and eliminated by the cell. In addition, CHIP also regulates the signal transduction of the insulin receptor. CHIP binds ubiquitin to the receptor to degrade it and stop the activation of life-extending gene products.
