Abstract
The SCF ubiquitin ligase complex regulates diverse cellular functions by ubiquitinating numerous protein substrates. Cand1, a 120 kDa HEAT repeat protein, forms a tight complex with the Cul1-Roc1 SCF catalytic core, inhibiting the assembly of the multisubunit E3 complex. The crystal structure of the Cand1-Cul1-Roc1 complex shows that Cand1 adopts a highly sinuous superhelical structure, clamping around the elongated SCF scaffold protein Cul1. At one end, a Cand1 β hairpin protrusion partially occupies the adaptor binding site on Cul1, inhibiting its interactions with the Skp1 adaptor and the substrate-recruiting F box protein subunits. At the other end, two Cand1 HEAT repeats pack against a conserved Cul1 surface cleft and bury a Cul1 lysine residue, whose modification by the ubiquitin-like protein, Nedd8, is able to block Cand1-Cul1 association. Together with biochemical evidence, these structural results elucidate the mechanisms by which Cand1 and Nedd8 regulate the assembly-disassembly cycles of SCF and other cullin-dependent E3 complexes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.