1. The thrombin receptor has now been cloned and found to be a member
of the G-protein-coupled seven-transmembrane domain receptor family. 2
. The receptor has been detected directly in platelets, endothelial ce
lls and smooth muscle cells and studies using receptor-derived peptide
s have demonstrated that this receptor may be the one responsible for
many of the actions of thrombin in platelets, endothelial cells, smoot
h muscle cells, fibroblasts, mesangial cells and neural cells. 3. The
receptor appears to be activated by the novel mechanism of cleavage by
thrombin to yield a new N-terminus which then interacts with the rece
ptor as a tethered ligand to initiate cell activation.