Surface exposure of α_IIbβ₃ and α_vβ₃ complexes in CHO cells transfected with α_IIb and either normal or mutated forms of β₃ (A) CHO cells were transiently cotransfected with cDNAs encoding normal α_IIb and either normal or mutant forms of β₃, and the level of surface expression of α_IIbβ₃ complexes was determined by flow cytometry using a mAb directed against α_IIb (▦) or β₃ (□). (B) Cells were transfected with either normal or mutant forms of β₃, and expression of surface complexes with endogenous α_v was evaluated using a mAb directed against α_vβ₃. The results are expressed as means ± SEMs of at least 4 independent experiments performed in duplicate.