G-protein-coupled receptors (GPCRs) are a large, diverse eukaryotic membrane group. They handle messaging for cells and signal the presence or absence of essential nutrients or other useful information sent by other cells. They are also binding sites for many cell signaling molecules. As a result, many pharmaceutical drugs on the market target GPCRs. In diabetes, GPCRs play a role in regulating hormones essential for maintaining blood glucose. In cancer, responses to tumors and cell growth are mediated by GPCRs and they also are a binding site for ligands and their overexpression is often seen in tumors. The Proteinase-activated receptors (PARs) are a diverse member of the GPCR family. They are activated primarily by proteases and are comprised of 4 types, with PAR1, PAR3, and PAR4 being activated by thrombin and PAR2 activated by trypsin. Upon protease cleavage, a tethered ligand is exposed at the N-terminus that is able activate intracellular signaling by binding to a conserved region in the second extracellular loop. PAR1 and PAR2 are expressed by a wide number of tumor cells including breast and colon cancers, suggesting a role in angiogenesis. PAR-activating peptides (PAR-APs) mimic the tethered ligand domains of the PARs and can activate by stimulating receptors in a protease-independent manner. Peptides International offers a variety of PAR-AP agonists and antagonists for your research needs.
2. B.T. Layden et al., Nature Education, 3(9),13 (2010).
3. R. Lappano & M. Maggiolini, Acta Pharmacol Sin., 33(3), 351 (2012).
For more information on PAR-APs, take a look at our recently updated brochure here.
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