P-selectin modulation in haemostasis: one size fits all?

Haemostasis and inflammation are tightly linked reactions primarily designated as post-traumatic protection mechanisms. Both reactions require the recruitment of specialized cells with specific functions. Recruitment of cells from circulating blood is a precisely regulated, receptor-mediated process that prevents inadvertent (e.g. thrombosis) and insufficient (e.g. bleeding) effects. P-selectin is a leukocyte-adhesion receptor but is also expressed on platelet and endothelial cell surfaces. It promotes interactions of leukocytes with platelets and endothelial cells, enabling leukocyte and platelet rolling on activated endothelial surfaces. Endothelial rolling of circulating cells represents an intermediate step before firm adhesion that still enables detachment.