Table 1.
Molecular characteristics and physiopathological roles of immune aGPCRs.
| Receptor | Expression in Immune Cells | Ligand/Interacting Partner | Physiopathological Functions in the Immune System |
|---|---|---|---|
| ADGRB1/ BAI1 |
Macrophage, gastric phagocyte, microglia, T-ALL * | LPS, PS, C1q, CD36, αvβ5 integrin, RTN4Rs | Apoptotic cell clearance, colonic inflammatory disorders, HDL biogenesis, microglial neuronal removal, bacteria phagocytosis, anti-viral response, T-ALL pathogenesis. |
| ADGRE1/ EMR1 (Emr1, F4/80) |
Monocyte, macrophage, eosinophil, and DC | N/S | Emr1 (F4/80): Anti-intracellular bacterial infection, induction of Ag-specific peripheral immune tolerance. EMR1: homeostatic control of human eosinophils. |
| ADGRE2/ EMR2 |
Monocyte, macrophage, granulocyte, mast cell, and DC | DS, CD55, FHR1 | Neutrophil activation, differentiation and inflammatory activation of macrophage, NLRP3 inflammasome activation, vibration-induced mast cell activation, and degranulation (VU, hereditary α-tryptasemia). |
| ADGRE5/ CD97 |
T and B lymphocytes, monocyte, macrophage, granulocyte, DC, HSPCs, AML, BL, LSC |
DS, CD55, CD90 (Thy-1), α5β1 integrin, LPAR1 | Leukocyte adhesion/trafficking, homeostasis and anti-bacterial response of granulocytes, activation, and expansion of T cell subsets, homeostasis and Agpresenting functions of splenic cDC2s, IS stability, regulation of hematopoiesis and LSC maintenance. |
| ADGRG1/ GPR56 |
NK, cytotoxic T cells, TPH and Treg cells, TILs, platelet, HSPCs, AML, LSC |
CD9/CD81, TG2, collagen III, laminin, heparin/HS, progastrin, L-Phe, PS | NK inhibitory receptor, up-regulated expression in T cell subsets of RA, JIA, and various cancer types, platelet activation in response to exposed collagen and blood flow, hematopoietic development, tumorigenesis of AML. |
| ADGRG3/ GPR97 |
Gpr97: pre-B cells and thymocytes. GPR97: neutrophil and eosinophil |
N/A mPR3 (PR3 + CD177) |
Mouse: B-lymphocyte fate decision, obesity-associated macrophage inflammation, pathogenic modulation of AKI and EAE. Human: inflammatory activation of neutrophilic granulocytes. |
* Abbreviations: T-ALL, T-cell acute lymphoblastic leukemia; RTN4Rs, Reticulon-4 receptors; DS, dermatan sulfate; FHR1, factor H-related protein 1; VU, vibratory urticarial; HSPCs, hematopoietic stem and progenitor cells; AML, acute myeloid leukemia; BL, Burkitt lymphoma; LSC, leukemic stem cell; LPAR1, lysophosphatidic acid receptor 1; IS, immunological synapse; TG2, transglutaminase-2; HS, heparin sulfate; PS, phosphatidylserine; AKI, acute kidney injury; EAE, experimental autoimmune encephalomyelitis.