The anaphase promoting complex/cyclosome (APC/C) is a large multimeric ubiquitin E3 ligase that regulates the eukaryotic cell cycle in processes such as chromatid segregation and completion of mitosis. It catalyses the polyubiquitylation of a diverse array of mitotic regulatory proteins and targets them for proteasomal degradation. Target selection also involves a co-activator protein (either Cdc20 or Cdh1) together with core APC/C subunits. Here, a cryo-EM structure of APC/CChd1 bound to a D-box peptide substrate is presented. The structure provides important insight into the recognition and catalytic mechanism of APC/C substrates.
- Paula C. A. da Fonseca
- Eric H. Kong
- David Barford