Figure 1. A model for the interaction of local conditions with the platelet signaling network resulting in heterogeneous platelet plug architecture.

A) A description of the heterogeneous architecture of the platelet plug observed in intravital imaging studies following focal injuries in the microcirculation. The platelet mass is comprised of at least two distinct regions, termed the core and outer shell, identified based on the secretion of the α-granule marker P-selectin. Additional properties of these regions are also indicated. Recent observations suggest that the endothelium is an important source of procoagulant membranes (yellow). B) Data suggest that the development of the heterogeneous architecture described in A is the result of partially overlapping agonist gradients within the platelet mass emanating from the site of injury.