Cullin Ubiquitin E3 Ligases

Synonyms

Cullin-containing ubiquitin E3 ligases; Cullin-RING ubiquitin E3 ligases (CRLs)

Definition

The cullin-RING ubiquitin E3 ligases (CRLs) are the largest family of multi-subunit ubiquitin E3 ligases in eukaryotes. CRLs share a structural archetype characterized by the presence of interchangeable substrate receptors assembled onto a core catalytic complex consisting of a cullin family member and a RING protein, RBX1 (ROC1 or Hrt1) or RBX2 (ROC2). The members of the human cullin family comprise cullin 1 (CUL1, CDC53), cullin 2 (CUL2), cullin 3 (CUL3), cullin 4A (CUL4A), cullin 4B (CUL4B), cullin 5 (CUL5), cullin 7 (CUL7), and cullin 9 (CUL9), each serves as a scaffold protein to assemble a subfamily of CRL E3 ligases. A cullin uses a conserved globular C-terminal domain (cullin homology domain) to recruit the catalytic RING protein and a series of N-terminal repeats of a five-helix bundle (cullin repeats) to modularly interact with different adaptor proteins and substrate receptors...