Thrombin receptor glycoprotein receptors

Amino acid receptors Monoamine receptors Lipid receptors Purine receptors Neuropeptide receptors Peptide hormone receptors Chemokine receptors Glycoprotein receptors Protease receptors Metabotropic glutamate and GABAb receptors Adrenoceptors, dopamine and 5-HT receptors, muscarinic and histamine receptors Prostaglandin, thromboxane and PAF receptors Adenosine and ATP (P2Y) receptors Neuropeptide Y, opiate, cholecystokinin VIP, etc. Angiotensin, bradykinin, glucagon, calcitonin, parathyroid, etc. Interleukin-8 TSH, LH/FSH, chorionic gonadotropin, etc. Thrombin... 

Cook NS, Zerwes H-G, Tapparelli C et al. (1993) Platelet aggregation and fibrinogen binding in human, rhesus monkey, guinea-pig, hamster and rat blood activation by ADP and thrombin receptor peptide and inhibition by glycoprotein Ilb/IIIa antagonists. Thromb Haemostasis 70 531-539... 

Figure 7. A schematic diagram of the proposed ligand binding domains, shown in light grey, in various GPCRs. The helices are shown as cylinders, the loops, N-termini and C-termini are shown as lines. (A) Biogenic amine receptors, (B) Peptide receptors, (C) Glycoprotein hormone receptors, (D) Thrombin receptor.

The two platelet membrane glycoproteins for which the strongest evidence exists at the present time that they are thrombin receptors are a specific form of the GPIb-DC-V conq>lex and PARI, the protease-activated thrombin receptor these will be discussed next in this review. Based on their apparent ability to form complexes with a hrombin, several other proteins had previously t en proposed as thrombin receptors but in only a few cases were the necessary further studies carried out to test these hypotheses. Protease nexin 1 was proposed as a thrombin receptor based on the similar time courses of complex formation and platelet activation but it was subsequently found that protease nexin 1 cannot be a receptor since it is an internal conq>onent of platelets that is expressed on the surface only ater activation. Glycoprotein V has also been proposed as a thrombin receptor based on the feet that it can be cleaved by low concentrations of a-thrombin but subsequent studies (reviewed in ) showed that there was no consistent relationship between the rate or extent of GPV hydrolysis and the extent of platelet activation induced by a-thrombin. Another thrombin-activatable receptor, PAW, has been identified in mouse platelets but not in human platelets using a reverse transcriptase/ polymerase chain reaction approach (unpublished data and S.Coughlin, personal communication). PAR3 has, however, been reported cloned from a human platelet cDNA library. ... 

Liu L, Freedman J, Homstdn A, Fenton JW,H, Song Y, Ofosu FA Binding of thrombin to the G-protein-linked receptor, and not to glycoprotein Ib, precedes thrombin-mediated platdd activation. J Biol Chem 272 1997,1997... 

Ward CM, Andrews RK, Smith AI, Bemdt MC Mocarhagin, a novel chbra venom metallc oteinase, cleaves the platelet vtm Willd)rand factcx- receptor glyooprotdn Iba. Identification of the sulfated tyrosine/anicHUC sequence Tyr-276 -Glu-282 of glycoprotein Iba as a binding site for vcm Willebrand factor and a-thrombin Biochemistry 35 4929,1996... 

Greco NJ, Tandon NN, Jones GD, Komhauser R, Jackson B, Yamamoto N, Tanoue K, Jamiescm GA. Contributions of glycoprotein Ib and the seven transmembrane domain receptor to increases in platdd cytoplasmic [Ca2+] induced by alpha- thrombin. Biochemistry 1996 35 906-14. 

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