PAR1 Antibody (YA3908)

Protease-activated receptor 1 (PAR1) is a proteolytically activated GPCR that links thrombin or PAR1-selective agonist stimulation to cellular signaling programs in platelets, neurons, astrocytes, fibroblasts, endothelial cells, and kidney cells^[1][2][3]. Mechanistically, PAR1 couples to Gq/11, Gi/o, and G12/13 pathways, while discrete residues in its second intracellular loop selectively control Gq/11-dependent inositol phosphate and calcium signaling^[4]. In neurons, PAR1 activation drives 2-arachidonoylglycerol retrograde signaling, activates presynaptic CB1 receptors, and suppresses inhibitory synaptic transmission^[2]. In inflammatory and injury models, thrombin-PAR1 signaling promotes astrocyte proliferation, reverses stellation, inhibits migration, and activates MAPK/NFκB inflammatory responses after spinal cord injury^[1]. PAR1 also contributes to tissue remodeling, because thrombin and the PAR1 agonist TFLLR stimulate fibroblast-mediated collagen gel contraction through PAR1 and PKC-ε^[3]. Compared with PAR4, PAR1 in human platelets shows homologous desensitization, whereas PAR4 signaling can restore PAR1-dependent aggregation through PKC-mediated granule release^[5]. For experimental applications, PAR1 agonists such as TFLLR or SFLLRN model receptor activation, while inhibitors such as dabigatran, SCH79797, and PZ-128 help dissect thrombin cleavage, receptor signaling, platelet biology, and vascular disease mechanisms^[6][7][8].