| 背景 |
NEDD8 is a ubiquitin-like modifier most well-studied for its role in activating the largest family of ubiquitin E3 ligases, the cullin-RING ligases (CRLs). Conjugation of the ubiquitin-like (Ubl) protein NEDD8 (neural precursor cell expressed developmentally downregulated protein 8) to target proteins, or neddylation, is a fundamental biological process that controls many key cellular functions, including cell cycle progression, the DNA damage response, and apoptosis. The most well-studied target for NEDD8 conjugation are the cullins (CUL1,−2,–3,−4A,−4B,−5, and −7), which are the scaffold subunits of the largest family of ubiquitin E3 ligases, the cullin-RING ligases (CRLs). NEDD8 transfer from the E2 to a lysine (Lys) residue within the cullin promotes conformational changes that increase the catalytic activity of the CRL, while also blocking the binding of the CRL exchange factor CAND1. Structural changes induced by NEDD8 conjugation to cullin subunits ultimately contribute to the efficient ubiquitylation of downstream CRL substrates and their degradation by the 26S proteasome. Several non-cullin neddylation targets have been discovered: p53, E2F1, ribosomal protein L11, Smurf1 and Histone H4 and so on. |
