Protein degradation is an important process that enables cells to eliminate abnormal or unnecessary proteins, recycle protein components, and adapt to changing cellular conditions.
Ubiquitination is one of the pathways cells utilize to degrade proteins. In this pathway, a protein called ubiquitin ligase tags a target protein with ubiquitin, which serves as a signal for protein degradation.2 Other proteins, such as cereblon, recruit specific target proteins, ensuring that only proteins that need to be degraded are marked with ubiquitin.3
Lenalidomide is a drug that binds to cereblon at its target protein-binding site. This alters the target protein specificity of cereblon towards another family of proteins called Ikaros. As a result, Ikaros proteins are marked with ubiquitin and degraded.4
Ikaros is a protein essential for the development of B cells, a type of immune cell.5 Some cancers that originate from B cells, such as multiple myeloma, rely on Ikaros to drive their uncontrolled growth.4 Therefore, lenalidomide, by leading to Ikaros degradation, halts their growth and ultimately leads to cancer cell death.