Activation of human integrin αIIbβ3 was assessed using the activation-specific human αIIbβ3 antibody PAC1 (BD Bioscience; #340535) and goat anti-mouse IgG secondary antibody Alexa 633 conjugate (Life Technologies; #A-21050). αIIbβ3-CHO cells were developed and cultured as described previously (23 (link)). EGFP-fused talin-H and/or FLAG-tagged DOK-1 expression constructs were transfected into αIIbβ3-CHO cells using Lipofectamine 2000 (Invitrogen, Carlsbad, CA). pEGFP vector (Clontech Laboratories, Mountain View, CA) or pCMV-tag 2B (Stratagene) was transfected as empty vector to adjust the amount of plasmid DNA to be transfected. 24 hours after transfection, the cells were collected and PAC1 binding was analyzed by flow cytometry (FACS LSR II, Becton Dickinson), gating only on the EGFP positive cells.