GP VI down-regulation is inhibited by metalloproteinase inhibitors. Washed platelets (3 × 10⁸/mL) were pre-incubated in the presence (broken lines) or absence (solid lines) of 300 μM GM6001. Platelets were stimulated with 25 μg/mL mAb 9012.2 (A) or left resting (B) at 37°C for 45 minutes. Samples were fixed in 1% paraformaldehyde and diluted, labeled for 1 hour with biotinylated-convulxin (50 ng/mL), and stained with fluorescein-streptavidin before analysis. Data were collected and analyzed using a FACScan flow cytometer and CELLQuest software. Results shown are representative of 3 independent experiments.