Which protein complex is responsible for delaying mitosis in case of spindle defects?
Accurate chromosome segregation requires that all kinetochores achieve amphitelic attachment to spindle microtubules from opposite poles and generate tension. Unattached or improperly attached kinetochores generate wait signal that delays onset of anaphase to prevent mis-segregation. This delay is enforced by mitotic checkpoint complex, abbreviated MCC, composed of Mad2, Bub3, BubR1 (Mad3 in yeast), and Cdc20. At unattached kinetochores, scaffold protein Knl1 is phosphorylated by Mps1, recruiting Bub1-Bub3 and Mad1-Mad2 complexes that catalyze conformational conversion of open Mad2 to closed f
Ref: Musacchio & Salmon, Nature Rev Mol Cell Biol 2007, Spindle Assembly Checkpoint; Lara-Gonzalez et al., Curr Biol 2012, MCC Functions.