Mitotic checkpoint, kinetochore tension sensing, and APC/C activation
The Spindle Assembly Checkpoint (SAC) is a surveillance mechanism that delays anaphase until every chromosome achieves proper bi-oriented attachment to spindle microtubules. Unattached kinetochores catalyze formation of the Mitotic Checkpoint Complex (MCC), which inhibits the Anaphase-Promoting Complex/Cyclosome (APC/C). Only when all kinetochores achieve amphitelic attachment and sufficient inter-kinetochore tension does MCC production cease, allowing APC/C to target securin and cyclin B for degradation, triggering anaphase.