Proteinase-activated receptors
| IUPHAR recommended name | PAR1 | PAR2 | PAR3 | PAR4 |
| IUPHAR receptor code | 2.1:PAR:1:PAR1:HUMAN:00 | 2.1:PAR:2:PAR2:HUMAN:00 | 2.1:PAR:3:PAR:3:HUMAN:00 | 2.1:PAR:4:PAR:4:HUMAN:00 |
| Alternate designators | Thrombin receptor | Trypsin receptor | Thrombin receptor | Thrombin receptor |
| Receptor variants | F240S mutation (h) | |||
| Amino acid composition | 425 aa (h)1-a | 397 aa (h) | 374 aa (h) | 385 aa (h) |
| Agonist proteinases Xa does | Thrombin > trypsin Thrombin ≅ trypsin Cathepsin G; factors VIIa/X | Trypsin, tryptase, trypsin 2, matriptase/MT-serine protease 1 Factor Xa/TF/VIIa, Der p3, Der p9 | Thrombin ≫ trypsin > factor Proteases cleavage but receptor does not generate a calcium signal | Thrombin ≅ Trypsin Cathepsin G; factors VIIa/X |
| Inactivating proteinases | Cathepsin G, proteinase 3, elastase, plasmin, chymase | Unknown | Unknown | Unknown |
| Tethered ligand sequences | SFLLR (h), SFFLR (m,r) | SLIGKV (h), SLIGRL (m,r) | TFRGAP (h), SFNGGP (m) | GYPGQV (h), GYPGKF (m) |
| Subtype selective peptide agonists | TFRIFD1-b | SLIGKV-NH2, SLIGRL-NH2 | GYPGKF-NH2 1-c | |
| TFLLR-NH2 | Trans-cinnamoyl-LIGRLO-NH2 | GYPGQV-NH2 AYPGKF-NH2 | ||
| Antagonists | Trans-cinnamoyl-parafluoro-Phe-paraguanidino-Phe-Leu-Arg-Arg-NH2 1-d | |||
| Mercaptopropionyl-Phe-Cha-Arg-Lys-Pro-Lys-Pro-Asn-Asp-Lys-NH2 1-f | TRANS-cinnamoyl-YPGKF-NH2 1-e | |||
| Non-peptide antagonists: RWJ56110 and RWJ58259 | ||||
| Signal transduction mechanisms | Gq/11 (increased IP3/DAG); Gi; G12/13 | —1-g | None known | — g |
| Gene/chromosome | F2R/5q13 (h) | F2RL1/5q13 (h) | F2RL2/5q13 (h) | F2RL3/19p12 (h) |
| F2R/13D2 (m) | F2RL1/13D2 (m) | F2RL2/13D2 (m) | F2RL3/8B3.3 (m) | |
| NCBI accession no. | M62424 (h) | U34038 (h) | U92971(h) | AF080214, AF055917 (h) |
| L03529 (m) | Z48043(m) | U92972 (m) | AF080215 (m) | |
| M81642 (r) | U61373(r) |
↵1-a The IUPHAR receptor code is provided for each human (h) PAR, but not for murine (m), or rat (r) PARs.
↵1-b TFRIFD is the Xenopusthrombin receptor tethered ligand domain (the human PAR1tethered ligand domain sequence, SFLLRN, activates both PAR1 and PAR2 receptors).
↵1-c AYPGKF is 10 times more potent than the natural human (GYPGQV) or murine (GYPGKF) tethered ligand sequences, which are also PAR4 selective.
↵1-d May also act at PAR2 as agonist; also designated BMS 200261.
↵1-e Validated only in rat platelets.
↵1-f Antagonizes PAR1; acts as an agonist at PAR2.
↵1-g Stimulates phosphositide turnover through an uncharacterized G protein, probably Gq/11; Gi interactions with PAR2 not evaluated; PAR4 believed not to interact with Gi.