Structure of the Cand1-Cul1-Roc1 complex reveals regulatory mechanisms for the assembly of the multisubunit cullin-dependent ubiquitin ligasesGoldenberg, S.J., Cascio, T.C., Shumway, S.D., Garbutt, K.C., Liu, J., Xiong, Y., Zheng, N.
(2004) Cell 119: 517-528
- PubMed: 15537541
- DOI: https://doi.org/10.1016/j.cell.2004.10.019
- Primary Citation of Related Structures:
- PubMed 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 beta 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.
Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195, USA.