Rotary-stained electron micrographic images of αIIbβ3. The complex is shown in the absence of detergent (A) or bound to fibrinogen (C). Schematic representations of each are shown in panels B and D. Note that the integrin stalks containing the hydrophobic transmembrane domains have a tendency to self-associate, while the head domain (arrows) binds fibrinogen (red outline). Adapted from Carrell et al¹⁷  and Weisel et al18 with permission.