Schematic drawing and electron micrograph of the GPIb-FLNa complex from human platelets. (A) The cytoplasmic domain of GPIbα of the GPIb-IX-V complex binds to actin filaments through FLNa. (B) GPIb-FLNa complex from human platelets. Coomassie-blue-stained SDS-PAGE (10%) of a concentrated GPIb-FLNa complex (left). Immunoblot of the GPIb-FLN complex with anti-GPIbα mAb (WM23) (center). The same blotting membrane was subsequently blotted with an anti-FLNa mAb 3-14 (right). (C) Electron micrographs of rotary-shadowed recombinant FLNa molecules (top) and GPIb-FLNa complexes (bottom).