Disclosed herein are in vivo engineered cereblon protein and methods of making the same. The in vivo engineered cereblon protein can include a site-specific non-naturally occurring modification at cysteine 287 as set forth in SEQ ID NO:1, or cysteine 286 as set forth in SEQ ID NO:2 or 3, the modification comprising a moiety resulting from an in vivo Michael addition reaction between an exogenous Michael acceptor and the cysteine 287 as set forth in SEQ ID NO:1, or cysteine 286 as set forth in SEQ ID NO:2 or 3.