Site-specific thrombin receptor antibodies inhibit Ca2+ signaling and increased endothelial permeability

The thrombin receptor domains responsible for receptor activation in endothelial cells were studied using site-specific antibodies. Results of experiments on polyclonal antibodies directed against peptide sequences corresponding to postulated binding sites of thrombin suggested a critical role for the thrombin receptor's NH2-terminal extension and loop 2 sites. These binding sites influenced receptor activation in endothelial cells, which in turn lead to increased intracellular calcium and transendothelial permeability to albumin.