Definition

An orally bioavailable modulator of the E3 ubiquitin ligase complex containing cereblon (CRL4-CRBN E3 ubiquitin ligase), with potential immunomodulating and antineoplastic activities. Upon oral administration, CRL4-CRBN modulator KPG-818 specifically targets and binds to cereblon (CRBN) of the E3 ubiquitin ligase (CRL4-CRBN) complex, thereby affecting the ubiquitin E3 ligase activity, and targeting certain substrate proteins for ubiquitination. This induces proteasome-mediated degradation of certain transcription factors, some of which are transcriptional repressors in T cells. This leads to modulation of the immune system, including activation of T lymphocytes, and downregulation of the activity of other proteins, some of which play key roles in the proliferation of certain cancer cell types. CRBN, the substrate recognition component of the CRL4-CRBN E3 ubiquitin ligase complex, plays a key role in the ubiquitination of certain proteins.