Inactivation of APC/C via CDC20 sequestration

In the sequestration model, the Mad2 molecules that dissociate from unattached kinetochores are perceived to bind to Cdc20, a protein that recruits specific substrates to the APC/C. Consequently, Mad2 indirectly inhibits the APC/C by sequestering its activator, Cdc20. This requires interaction between Mad1 and Mad2. Cdc20 and Mad1 bind to the same site on Mad2.

在隔离模型中，Mad2 分子从未附着于着丝粒的分离状态感知并与之结合，该分子为 Cdc20 蛋白。Cdc20 蛋白负责招募特定的底物至 APC/C 复合物。因此，Mad2 通过隔离其激活剂 Cdc20，间接地抑制了 APC/C 的活性。这一过程需要 Mad1 与 Mad2 之间的相互作用。Cdc20 和 Mad1 均与 Mad2 上的同一位点结合。