Docking onto the endothelium: Trio directs leukocyte extravasation

Leukocyte extravasation describes the process by which white blood cells (leukocytes) travel across the endothelium lining the vasculature, into the underlying tissue. Effi-cient and tightly controlled leukocyte extravasation is of key importance in physiological processes such as immune surveillance and inflammation. Uncontrolled and excessive leukocyte extravasation is characteristic for chronic inflammatory diseases (e.g. rheumatoid arthritis, atherosclerosis, asthma), as well as for tumor cell metastasis. Thus, a deeper understanding of the key molecules that regulate excessive leukocyte extravasation aids to the development of novel therapeutics for treatment of these diseases. The research described in this thesis provides new insights into the signaling pathways in the endothelium that control leukocyte extravasation, with special emphasis on the crucial contribution of the GEF-enzyme Trio.