Extended Data Fig. 7: Visualisation of different orientations of the protein complexes formed by Arp2/3, SPIN90, and mDia1.
From: SPIN90 associates with mDia1 and the Arp2/3 complex to regulate cortical actin organization
Different combinations of complexes (binary or ternary) involving the Arp2/3 complex, SPIN90, and mDia1 were analyzed by electron microscopy and single particle analysis. For each protein complex, three-dimensional reconstructions were obtained from 3D classifications and compared to existing or generated crystal structures (see methods). a, Incubation of mDia1 and Arp2/3 resulted in a 3D structure which only accommodates Arp2/3, suggesting that mDia1 and Arp2/3 do not interact when SPIN90 is absent. b, Conversely, mixing the Arp2/3 complex and SPIN90 results in a complex for 76 % of the particles. Within the complex, SPIN90 (green) clearly appears as an additional density when compared with the truncated docked crystal structure. c, When compared with the Arp2/3-SPIN90 complex in B, the 3D envelope (resolution of 27 Å) resulting from the ternary complex (SPIN90-Arp2/3-mDia1) exhibits an additional density accommodating a dimer of FH2 domains for 22 % of the particles. (a-c) Each protein complex is subjected to a variety of rotations to visualize its full structure.
