Cullins are hydrophobic scaffold proteins for E3 ubiquitin ligases. They combine with ring box proteins (RBX) to form the CRL complex.[1] The CRL complex is essential in targeting proteins to ubiquitin-mediated destruction. Cullin-1 to 7 are part of the multi-subunit ubiquitin complex. Conjugation of cullin to NEDD8 modulates the activation of the CRL.
- Cullin-1 is part of the SCF (Skp-cullin-F-box containing) complex which catalyzes the ubiquitination of proteins.
- Cullin-2 is part of the ECS (Elongin-cullin-SOCS-box) complex.
- Cullin-3 is part of the BTB-Cul3 complex.
- Cullin-4A and 4B regulate various processes like DNA repair, chromatin remodeling and mitotic cell cycle.
- Cullin-5 inhibits cellular proliferation.
