Effect of homocysteine on the cellular localization of GRP78 and vWF. HUVEC plated on gelatin-coated glass coverslips were cultured in the absence (A,D) or presence (B,E) of 5.0 mmol/L homocysteine for 18 hours. After treatment, cells were fixed, permeabilized, and incubated with antibodies against either GRP78 (A,B) or vWF (D,E). Antibodies were subsequently detected using fluorescein-labeled secondary antibodies. Parallel experiments using normal mouse (C) or rabbit IgG (D) were performed to assess nonspecific immunofluorescence.