Fig. 2.

Schematic representation of SAC activity. A Unattached or misaligned kinetochores activate the KMN network, leading to recruitment of SAC proteins and conformational change of MAD2 (closed form, C-MAD2). This allows to the formation of the MCC, which sequestrate CDC20 leading to mitotic arrest. B Properly attached kinetochores satisfy the SAC, which allow the onset of anaphase through release of CDC20 from MAD2 (open, form, O-MAD2) the interaction between CDC20 and APC/C. APC/C^CDC20 complex promotes Cyclin B and Securin ubiquitination and degradation, starting sister chromatid separation