Review Article
Overview of Platelet Physiology: Its Hemostatic and Nonhemostatic Role in Disease Pathogenesis
Table 1
Platelet receptors in different activation stages (adapted from Kauskot and Hoylaerts, 2012 [
20]).
| (a) Platelet receptors in recruitment, adhesion, and aggregation |
| | Receptors | Present in | Family | Ligands | Comments |
| | Initiation of platelet recruitment | | GPIb-IX-V complex | Platelet surface | Leucine-rich repeat family | vWf, thrombin, FXI, FXII, P-selectin, HK, Mac-1, TSP-1 | Bernard-Soulier syndrome |
| | Platelet adhesion and aggregation | | GPVI | Platelet surface | Ig superfamily | Collagen, laminin | | | Platelet plasma membrane | Integrins | Collagen | | | ” | ” | Fibronectin | | | ” | ” | Laminin | | | ” | ” | Vitronectin, fibrinogen, vWf, osteopontin | | | ” | ” | Fibrinogen, fibrin, vWf, TSP-1, fibronectin, vitronectin | Glanzmann thrombasthenia | | CD148 | Platelet surface | Tyrosine phosphatase receptor | Unknown | Regulation of GPVI | | CLEC-2 | ” | C-type lectin receptor | Podoplanin (platelets? CLEC-2?) | |
|
|
| (b) Platelet receptors in the amplification phase |
| | Receptors | Present in | Family | Ligands | Comments |
| | P2Y1 | Platelet plasma membrane | G protein-coupled receptors | ADP | | | P2Y12 | ” | ” | ” | | | PAR1 | ” | ” | Thrombin | High affinity | | PAR4 | ” | ” | ” | Low affinity | | tPA | ” | ” | Thromboxane | | | PAF receptors | ” | ” | 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine | PAF: platelet activating factor | | PGE2 receptor (EP3) | ” | ” | PGE2 | | | Lysophosphatidic acid receptor | ” | ” | Lysophosphatidic acid | | | Chemokine receptors | ” | ” | Chemokines | | | V1a vasopressin receptor | ” | ” | Vasopressin | | | A2a adenosine receptor | ” | ” | Adenosine | | | b2 adrenergic receptor | ” | ” | Epinephrine | | | Serotonin receptor | ” | ” | Serotonin (5-hydroxytryptamin) | | | Dopamine receptor | ” | ” | Dopamine | | | P2X1 | ” | Ion channel | ATP | | | c-Mp1 | ” | Tyrosine kinase receptor | TPO | | | Insulin receptor | ” | ” | Insulin | | | PDGF receptor | ” | ” | PDGF | | | Leptin receptor | ” | Cytokine | Leptin | |
|
|
| (c) Platelet receptors in the stabilization phase and in the negative regulation of platelet activation |
| | Receptors | Present in | Family | Ligands | Comments |
| | Stabilization | | Eph receptor | Platelet plasma membrane | Tyrosine kinase receptor | Ephrin | | | Axl/Tyro3/Mer | ” | ” | Gas-6 | | | P-selectin | Platelet
α granule; comes in plasma membrane upon activation | C-type lectin receptor family | PSGL-1, GPIb, TF | Soluble
P-selectin: biomarker | | TSSC6 | Platelet plasma membrane | Tetraspanins | — | | | CD151 | ” | ” | — | | | CD36 | ” | Class B scavenger receptor | TSP1, oxLDL, VLDL, oxPL, collagen type V | Many functions | | TLT-1 | ” | Ig superfamily | Fibrinogen? | TLT-1 soluble form correlated with DIC | | PEAR1 | ” | Multiple EGF-like domain protein | — | Phosphorylated after platelet contact |
| | Negative regulation | | VPAC1 | Platelet plasma membrane | G protein-coupled receptors | PACAP | | | PECAM-1 | ” | Ig superfamily | PECAM-1, collagen, glycosaminoglycans | | | G6B-b | ” | ” | — | | | PGI2 receptor (IP) | ” | G protein-coupled receptors | PGI2 | Prostacyclin released from endothelial cells | | PGD2 receptor | ” | ” | PGD2 | | | PGE2 receptor (EP4) | ” | ” | PGE2 | |
|
|
