Proteinase-Activated Receptor 1 Antibodies
Proteinase-activated receptors (PARs) are unique members of the GPCR superfamily activated by proteolytic cleavage of their amino terminal exodomains. Agonist proteinase-induced hydrolysis unmasks a tethered ligand (TL) at the exposed amino terminus, which acts intramolecularly at the binding site in the body of the receptor to effect transmembrane signaling. TL sequences at human PAR1-4 are SFLLRN-NH2, SLIGKV-NH2, TFRGAP-NH2 and GYPGQV-NH2, respectively. Several proteinases, including neutrophil elastase, cathepsin G and chymotrypsin can have inhibitory effects at PAR1 and PAR2 such that they cleave the exodomain of the receptor without inducing activation of Gαq-coupled calcium signaling, thereby preventing activation by activating proteinases but not by agonist peptides. PAR1 receptor desensitization and internalization are regulated by phosphorylation of carboxyl-terminal serine412/serine413 (pS412/pS413-PAR1) and serine418 (pS418-PAR1). This nomenclature refers to the human PAR1 receptor. This phosphorylation motif is highly conserved across species but corresponds to pS417/pS418-PAR1 and pS423-PAR1 in mice and to pS419/pS420-PAR1 and pS425-PAR1 in rats. For more information on PAR1 pharmacology please refer to the IUPHAR database. For further reading refer to:
Hollenberg MD, Compton SJ. International Union of Pharmacology. XXVIII. Proteinase-activated receptors. Pharmacol Rev. 2002 Jun;54(2):203-17. doh: 10.1124/pr.54.2.203. PMID: 12037136.
Lin H, Liu AP, Smith TH, Trejo J. Cofactoring and dimerization of proteinase-activated receptors. Pharmacol Rev. 2013 Sep 24;65(4):1198-213. doi:10.1124/pr.111.004747. PMID: 24064459; PMCID: PMC3799237.
Bunnett N, DeFea K, Hamilton J, Hollenberg MD, Ramachandran R, Trejo J. Proteinase-activated receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database. IUPHAR/BPS Guide to Pharmacology CITE. 2019; 2019(4). Available from: https://doi.org/10.2218/gtopdb/F59/2019.4.