Effect of αIIb-Trp110Leu or -Trp110Arg substitutions on αIIbβ3 outside-in signaling–related functions and stability. (A) BHK cell adhesion to immobilized fibrinogen and to immobilized VWF-coated wells. Mean percentage of WT surface coverage ± SD is shown (mean of 3 different transfections). (B) Clot retraction of cells resuspended in DMEM in the presence of fibrinogen and thrombin and after incubation for 18 hours at 37°C. (C) αIIbβ3 complex stability measured by flow cytometry with P2 antibody in the presence and absence of 5mM EDTA. The results for WT and the 2 mutants are expressed as mean proportion ± SD of MFI P2 binding in the absence of EDTA.