MT1-MMP relocalizes to motility-associated membrane protrusions in monocytes migrating on FN, VCAM-1, or ICAM-1. MT1-MMP (green) and F-actin (red) were immunostained in monocytes attached to plates coated with 20 μg/mL FN or 10 μg/mL VCAM-1 or ICAM-1 for 2 hours (A) or 16 hours (B) and stimulated with 100 ng/mL MCP-1 for the last 2 hours. Differential interference contrast (DIC) images are shown in the insets as controls of cell morphology. Arrowheads indicate cellular membrane protrusions, lamellipodia and filopodia, where MT1-MMP is clustered.