The anaphase promoting complex/cyclosome (APC/C) is an essential multi-protein E3 ubiquitin ligase required for both chromosome segregation and exit from mitosis. This image shows one view of the mitotically active fission yeast APC/C at a resolution of ~25-Å (yellow). This structure was determined using single particle cryo-electron microscopy. Flanking the APC/C are images of Hela cells either in metaphase (left) or anaphase (right). Microtubules are labeled green, chromosome are labeled purple, and kinetechores are labeled pink. Images of stained mammalian cells were kindly provided by Dr. Ryoma “Puck” Ohi.