Structural analysis of human Cdc20 supports multisite degron recognition by APC/C.Tian, W., Li, B., Warrington, R., Tomchick, D.R., Yu, H., Luo, X.
(2012) Proc.Natl.Acad.Sci.USA 109: 18419-18424
- PubMed: 23091007
- DOI: 10.1073/pnas.1213438109
- Primary Citation of Related Structures:
- PubMed Abstract:
- Cdc20: a WD40 activator for a cell cycle degradation machine
(2007) Mol.Cell 27: 3
- KEN-box-dependent degradation of Bub1 spindle checkpoint kinase by the anaphase-promoting complex/cyclosome
Qi, W.,Yu, H.
(2007) J.Biol.Chem. 282: 3672
- Mad2-independent inhibition of APC-Cdc20 by the mitotic checkpoint protein BubR1
Tang, Z.,Bharadwaj, R.,Li, B.,Yu, H.
(2001) Dev.Cell 1: 227
The anaphase-promoting complex/cyclosome (APC/C) promotes anaphase onset and mitotic exit through ubiquitinating securin and cyclin B1. The mitotic APC/C activator, the cell division cycle 20 (Cdc20) protein, directly interacts with APC/C degrons--th ...
The anaphase-promoting complex/cyclosome (APC/C) promotes anaphase onset and mitotic exit through ubiquitinating securin and cyclin B1. The mitotic APC/C activator, the cell division cycle 20 (Cdc20) protein, directly interacts with APC/C degrons--the destruction (D) and KEN boxes. APC/C(Cdc20) is the target of the spindle checkpoint. Checkpoint inhibition of APC/C(Cdc20) requires the binding of a BubR1 KEN box to Cdc20. How APC/C recognizes substrates is not understood. We report the crystal structures of human Cdc20 alone or bound to a BubR1 KEN box. Cdc20 has a disordered N-terminal region and a C-terminal WD40 β propeller with a preformed KEN-box-binding site at its top face. We identify a second conserved surface at the side of the Cdc20 β propeller as a D-box-binding site. The D box of securin, but not its KEN box, is critical for securin ubiquitination by APC/C(Cdc20). Although both motifs contribute to securin ubiquitination by APC/C(Cdh1), securin mutants lacking either motif are efficiently ubiquitinated. Furthermore, D-box peptides diminish the ubiquitination of KEN-box substrates by APC/C(Cdh1), suggesting possible competition between the two motifs. Our results indicate the lack of strong positive cooperativity between the two degrons of securin. We propose that low-cooperativity, multisite target recognition enables APC/C to robustly ubiquitinate diverse substrates and helps to drive cell cycle oscillations.
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.