Figure 3. Structure of the mitotic checkpoint complex (MCC) and its inhibition of the anaphase-promoting complex/cyclosome (APC/C).

(a) The crystal structure of the MCC from S. pombe (Protein Data Bank (PDB) 4AEZ).¹⁴ (b) A cryo-EM reconstruction of APC/C^MCC (PDB 6TLJ).⁴⁴ The APC/C subunits are displayed using grey surface representation in ChimeraX,¹⁹⁸ Cdc20^APC/C is colored in cyan, BubR1 in pink, Cdc20^MCC in green, and Mad2 in blue. (c) Two views of the MCC bound to and inhibiting Cdc20^APC/C (PDB 6TLJ).⁴⁴ (d) Schematic representation of BubR1. BubR1 domains involved in interacting with either Cdc20^MCC or Cdc20^APC/C are shaded dark pink and are highlighted in the structure in (c). All structures are displayed using ChimeraX.¹⁹⁸