Double labeling experiments showing that vWF and P-selectin follow a distinct intracellular route.

(A) The electron lucent elongated structures display immunolabeling for GPIb (5 nm gold) and can be identified as demarcation membranes. They do not express P-selectin (10 nm gold), which is detected in multivesicular bodies (MvB). (B) vWF immunolabeling (5 nm gold) is detected in the lumen of the demarcation membrane system cisternae, which also express heavy labeling for GPIb (10 nm gold). The multivesicular bodies (MvB) are devoid of vWF labeling. (C) vWF (5-nm gold particles) is found within elongated cisternae of the demarcation membrane system, whereas P-selectin (10-nm gold particles) is detected in multivesicular bodies (MvB). (Panels A-C, original magnification × 65 100.)