Fig. 6.

Ribbon diagrams comparing the conformations of the subunits in fission yeast Arp2/3 complex in three cryo-EM structures: (sky blue) inactive structure; (tan) bound to Dip1; and (pink) branch junction. Curved arrows indicate domain rotations. The symbol β marks the part of the Arp2 D-loop that forms a β-sheet with ARPC3. The ribbon diagram at the lower right is the inactive Arp2/3 complex (PDB: 6W18) for orientation. The C-terminal helices of ARPC2 and ARPC4 bend more in the Dip1-activated Arp2/3 complex than in the branch junction.