A plot summarizing the interactions within the lid, based on interactions identified here in combination with those determined previously. The dashed line circling Rpn6 indicates that it is present in substoiciometric amounts. Rpn10 (in gray) is added to the model to emphasize the orientation of the complex relative to the base and the cellular environment. The two apparent clusters are labeled. Subunits are colored either red, purple, or blue, indicating their increasing exposure.