Analysis of GPIb and GPIX in CHOIX cells transiently transfected with GPIbβ. (A) CHOIX cells were additionally transfected with the wild-type GPIbβ, the mutant GPIbβ, or mock transfected with the expression plasmid alone. GPIb is readily detectable in cells transfected with plasmid alone (shaded area), the mutant (thin lines), or wild-type GPIbβ (bold lines). (B) There was a significant increase in the surface expression of GPIX when the wild-type GPIbβ (bold lines) is transfected into CHOIX cells, compared with the mock control (shaded area) or cells transfected with the wild-type GPIb, GPIX, and mutant GPIbβ (thin line). (C) CHOIX cells transfected with the wild-type GPIbβ (bold lines) were reacted with the complex specific antibody AK1. Again, there is a marked increase in surface fluorescence compared with either the mock transfected cells (shaded area) or the cells transfected with the mutant GPIbβ (thin lines).