Localization of VAMP isoforms in spread platelets. Localization of VAMP isoforms was determined in spread platelets using double staining immunofluorescence microscopy. Spread platelets were labeled with antibodies to (A) VAMP-3, (B) VAMP-8, and (C) VAMP-7 followed by staining with secondary antibodies labeled with Alexa 488 (row 1). Platelets were costained with Alexa 546–phalloidin to visualize actin structures (row 2). Merged images were evaluated to determine the localization of VAMP isoforms relative to actin structures in spreading platelets (row 3). VAMP-3 and VAMP-8 localize to the center of the spread platelet, whereas VAMP-7 localizes to peripheral lamellipodia and pseudopodia. Scale bars, 5 μm.