Increase in tissue factor concentration in endosomes in response to factor VIIa. Fibroblasts were exposed to control vehicle or FVIIa (10 nM) for 2 hours at 37°C. The cells were fixed, permeabilized, and immunostained with anti–human TF and antibodies against either EEA1 (A) or rab5 (B). Left panel represents TF staining, middle panel represents the staining for early endosomes (EEA1 or rab5), and the right panel represents the overlay of TF and EEA1 (or rab5) staining.