Table 1.
Various chemotaxis or phagocytosis-related receptors in microglia and its ligand(s) or interacted factors. Microglia are activated with various stimuli through the specific receptor of each stimuli. For detailed review of chemokines, pathogens, and factors associated with tissue damage recognized by microglia, refer to [19–21].
| Receptor type | Subtypes | Ligand(s)/interacted factors |
|---|---|---|
| CCR1 | CCL3 (MIP-1α), CCL5 (RANTES), CCL7 (MCP-3), CCL9 (MIP-1γ), CCL14 (HCC-1), CCL15 (HCC-2/leukotactin-1), CCL16 (HCC-4/LEC), CCL23 (MPIF-1) |
|
| Chemokine receptor | CCR2 | CCL2 (MCP-1), CCL7 (MCP-3), CCL8 (MCP-2), CCL13 (MCP-4), CCL16 (HCC-4/LEC) |
| CCR5 | CCL3 (MIP-1α), CCL4 (MIP-1β), CCL5 (RANTES) | |
| CXCR3 | CXCL9 (Mig), CXCL10 (IP-10), CXCL11 (I-TAC) | |
| CX3CR1 | CX3CL1 (Fractalkine) | |
|
| ||
| Purinergic receptor | P2X4, P2Y7, P2Y12 P2Y6 |
ATP, ADP UDP |
|
| ||
| TLR | TLR1 TLR2 TLR4 TLR6 TLR9 |
Triacyl lipopeptides Glycolipids, Hsp70, HMGB1, Aβ LPS, Hsp Diacyl lipopeptides CpG-DNA |
|
| ||
| Phosphatidylserine (PS) receptor | MFG-E8, Tim1, Tim4 RAGE |
PS of apoptotic cells Aβ, AGE, HMGB1 PS of apoptotic cells |
|
| ||
| Scavenger receptor (SR) | SR-AI/II (CD204), SR-BI, CD36 | Cellular debris, apoptotic cells, Aβ (CD36) |
|
| ||
| Immunoglobulin (Ig) receptor | FcγRI, FcγRIII | Ig-opsonized particles |
|
| ||
| Complement receptor (CR) | CR3 (MAC-1; CD11b/CD18) | Complement components, opsonized particles |
|
| ||
| Other phagocytosis-related receptor | CD14 CD47 CD200R TREM2 |
LPS, Aβ
SIRPα (CD172a) CD200 Hsp60, DAP12 |