| Aspect | Identity | Activation mechanism | Cleavage site / tethered ligand | Cofactor / heterodimer role with PAR4 | Downstream signaling evidence | Expression / cell types | Quantitative data | Key references |
|---|---|---|---|---|---|---|---|---|
| Mouse F2rl2 / PAR3 functional annotation | F2rl2 encodes protease-activated receptor 3 (PAR3), a thrombin receptor-like rhodopsin-family GPCR; literature retrieved for mouse aligns with UniProt O08675/PAR3 identity (pqac-00000000, pqac-00000005) | Activated by irreversible proteolytic N-terminal cleavage, principally by thrombin; APC also reported as a PAR3-cleaving protease; synthetic PAR3 agonist peptides can mimic tethered-ligand activation in some systems (pqac-00000000, pqac-00000001, pqac-00000005) | Mouse PAR3 is reported cleaved at Lys38/Thr39, exposing tethered ligand sequence TFRGAP…; Hänzelmann et al. used PAR3-activating peptide SFNGGP, reflecting PAR3 tethered-ligand mimic activity in islets (pqac-00000003, pqac-00000005, pqac-00000000) | On mouse platelets, PAR3 is best supported as a thrombin-binding cofactor/modulator for PAR4 rather than a robust autonomous signaling receptor; PAR3/PAR4 heterodimerization enhances thrombin cleavage of adjacent PAR4, with species difference vs humans (human platelets mainly PAR1/PAR4, low PAR3 ~150–200 copies) (pqac-00000012, pqac-00000013, pqac-00000014, pqac-00000015, pqac-00000019) | In mouse islets/β-cells, PAR3 activation increases exocytosis and Ca2+ via Gq→PLC→IP3/DAG, ER Ca2+ release, and PKC-sensitive signaling; broader PAR-family evidence supports GPCR, Ca2+, MAPK/ERK, β-arrestin/internalization paradigms, but direct platelet-autonomous PAR3 signaling remains weak/uncertain (pqac-00000002, pqac-00000001, pqac-00000007, pqac-00000013) | Platelets; mouse islets/β-cells; eosinophils in skin/AD model; broader tissue distribution reported in heart, kidney, pancreas, thymus, small intestine, stomach, lymph node, trachea, airway smooth muscle (pqac-00000003, pqac-00000000, pqac-00000008, pqac-00000009) | Thrombin 10 nM increased insulin secretion ~140% at 2 h, 87% at 12 h, 29% at 24 h; PAR3-AP 20 μM increased insulin secretion ~90% at basal glucose and ~130% at high glucose; PAR3-AP increased β-cell exocytosis ~70% and intracellular Ca2+ ~2-fold; H103 antibody against PAR3 cleavage region blocked thrombin effect; in eosinophil coculture, PAR3 decreased by −62 ± 12%; eosinophil RNA-seq source comparison used n=4 mice/source, intracellular-flow coculture assay n=6 (pqac-00000000, pqac-00000002, pqac-00000008, pqac-00000009) | Hänzelmann et al., 2015, Islets, https://doi.org/10.1080/19382014.2015.1118195; Li et al., 2024, Cell. Mol. Life Sci., https://doi.org/10.1007/s00018-024-05543-2; Posma et al., 2019, ATVB, https://doi.org/10.1161/ATVBAHA.118.311655; Cunningham et al., 2016, Biochem. Soc. Trans., https://doi.org/10.1042/BST20150282 (pqac-00000000, pqac-00000002, pqac-00000008, pqac-00000014, pqac-00000019) |


*Table: This table summarizes core functional annotation for mouse F2rl2/PAR3, integrating identity, activation, platelet cofactor function with PAR4, signaling evidence, expression, and key quantitative findings from primary studies. It is useful as a compact evidence map for gene-function curation.*