In Vitro Assays for the Anaphase-Promoting Complex/Cyclosome (APC/C) in Xenopus Egg Extracts

The anaphase-promoting complex/cyclosome (APC/C), a large (20S) multisubunit E3 ligase, has an essential role to ubiquitylate numerous substrates at specific times during mitosis and G1 phase as well as in meiosis. The deregulation of the APC/C causes cell death or genomic instability, which is a hallmark of cancers. Although 13 years have passed since its discovery, the molecular mechanisms of the APC/C-dependent ubiquitylation and proteolysis are still poorly understood. The development of in vitro systems enables the identification of new substrates and investigation of the molecular mechanisms by which the APC/C recognizes its substrates. This chapter describes in vitro assays reconstituted in Xenopus egg extracts.