protease-activated receptor-3 (par-3) , human

TFRGAP-amide, human PAR-3-derived tethered ligand sequence which does not activate PAR-3 but rather activates PAR-1 and PAR-2, either in Jurkat or in other PAR-expressing cells.

Protease-Activated Receptor-3 (PAR-3) (1-6), human TFA, is a peptide that acts as an agonist for the proteinase-activated receptor (PAR-3) [1].

PAR2 (1-6) amide is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of human PAR2 and residues 37-42 of the full-length sequence.1It binds to NCTC 2544 cells expressing human PAR2 (Ki= 9.64 μM in a radioligand binding assay) and induces calcium mobilization in the same cells (EC50= 0.075 μM).2PAR2 (1-6) amide (100 μM) reduces colony formation of A549 lung cancer cells.1It induces superoxide production and degranulation in isolated human eosinophils when used at a concentration of 500 μM.3PAR2 (1-6) amide (5 μmol/kg) induces tear secretion in rats when used in combination with amastatin .4 1.Bohm, S.K., Kong, W., Bromme, D., et al.Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2Biochem. J.314(Pt 3)1009-1016(1996) 2.Kanke, T., Ishiwata, H., Kabeya, M., et al.Binding of a highly potent protease-activated receptor-2 (PAR2) activating peptide, [3H]2-furoyl-LIGRL-NH2, to human PAR2Br. J. Pharmacol.145(2)255-263(2005) 3.Miike, S., McWilliam, A.S., and Kita, H.Trypsin induces activation and inflammatory mediator release from human eosinophils through protease-activated receptor-2J. Immunol.167(11)6615-6622(2001) 4.Nishikawa, H., Kawai, K., Tanaka, M., et al.Protease-activated receptor-2 (PAR-2)-related peptides induce tear secretion in rats: Involvement of PAR-2 and non-PAR-2 mechanismsJ. Pharmacol. Exp. Ther.312(2)324-331(2005)

SFNGGP-NH2 is a biologically active peptide that interacts with Protease-Activated Receptor 3 (PAR-3), a high-affinity thrombin receptor. Human cutaneous mast cells express PAR-3 mRNA, implicating a role in itch mechanotransduction, with both histamine-dependent and independent pathways reported. While PAR-3 alone does not induce itch, it may potentiate itch when co-expressed with PAR-4, enhancing thrombin's action. This suggests that PAR-3's primary function is not as a signal transmitter across the membrane, but rather as a cofactor necessary for PAR-4 activation.