Compositions and methods for selective protein degradation

A fusion polypeptide comprising:

• (i) a CRBN (cereblon)-binding polypeptide, and
• (ii) a chimeric antigen receptor (CAR) that comprises, in a N-terminal to C-terminal direction, an antigen binding domain, a transmembrane domain, and one or more intracellular signaling domains, wherein the CRBN-binding polypeptide comprises the amino acid sequence of SEQ ID NO:
• 3 or SEQ ID NO:
• 1.