Fig. 4. Inhibition of leukocyte extravasation by annexin A1. Directed leukocyte transmigration through activated endothelium (red) into inflamed/infected tissue is mediated by chemoattractant receptors of the FPR family, which are targets of fMLF (left). This directed migration is inhibited in the presence of extracellular annexin A1 and/or N-terminal annexin A1 peptides, which are probably generated at sites of inflammation (right). An interaction of annexin A1 with FPR/FPRLs present on migrating leukocytes can trigger receptor desensitization and/or L-selectin shedding, leading to the observed block in directed leukocyte migration.