SLPI loses microtubular association after thrombin stimulation. Thrombin-stimulated wild-type platelets were stained with antibodies against β tubulin and either SLPI or the α-granule marker VWF. Following activation, SLPI is restricted to a single, central platelet compartment, similar to VWF, and, in contrast to resting platelets (see Figure 2A), no longer colocalizes with the rearranged MT filaments. Scale bars, 2 μm.