Through and beyond the wall: late steps in leukocyte transendothelial migration.

A combination of approaches has provided firm experimental support for a step-wise model of leukocyte adhesion to vascular endothelium under hemodynamic shear stress. However, leukocyte adhesion to vascular endothelium acquires functional significance only if coupled to transmigration and progression into extravascular tissues. As discussed here by Elisabetta Bianchi and colleagues, these latter processes involve the sequential activation of adhesion-dependent functional programs, carried out by structurally diverse multimolecular complexes.