Table 1:
Common astrocyte markers
| Protein/Marker | Description | Expression | Function | Antibody |
|---|---|---|---|---|
| Glial fibrillary acidic protein (GFAP) | An intermediate filament protein(Lee, Messing, Su, & Brenner, 2008) | Whole-brain astrocytes, overexpressed in reactive astrocytes | Important during brain development, Overexpresses during reactive astrocytosis | Anti-GFAP |
| EAAT1/GLAST | Astrocyte transporter (Miralles et al., 2001) | Whole-brain astrocytes | Transports L-Glutamate and Aspartate | Anti-GLAST, Anti-EAAT1 |
| EAAT2/GLT-1 | Astrocyte transporter (Miralles et al., 2001) | Whole-brain astrocytes but also expressed at lower levels on neurons(Petr et al., 2015) | Mediates uptake of L-Glutamate and Aspartate | Anti-EAAT2, Anti-GLT-1 |
| Glutamine synthetase | Astrocyte enzyme (Rose, Verkhratsky, & Parpura, 2013) | Whole-brain astrocytes | Catalyzes Glutamate to Glutamine conversion | Anti-Glutamine synthetase |
| S100 β | Calcium-binding protein (Z. Zhang et al., 2019) | Whole-brain astrocytes, *some Schwann cells and oligodendrocytes | Binds Zn2+ with high affinity and Ca2+ with medium affinity | Anti-S100 β |
| Alcohol dehydrogenase 1l1 (ALDH1L1) | Astrocyte enzyme (Cahoy et al., 2008) | Whole-brain astrocytes | Folate conversion | Anti-ALDH1L1 |
| Aquaporin-4 | Water channel protein (Mader & Brimberg, 2019) | End feet of astrocytes and some blood vessels | Water transportation and homeostatic control | Anti-Aquaporin-4 |
| N-myc downregulated gene 2 (NDRG2) | Tumor suppressor protein (Flügge et al., 2014) | Mature non-reactive astrocytes | Bind cytosol of protoplasmic and fibrous astrocytes | Anti-NDRG2 |
| Sulphorhodamine (SR101) ** | An astrocyte dye/Preferential astrocyte marker(Nimmerjahn, Kirchhoff, Kerr, & Helmchen, 2004; Rasmussen, Nedergaard, & Petersen, 2016) | Astrocytes and some oligodendrocytes | Spreads through the syncytium via astrocytic gap junctions(Rasmussen et al., 2016) | SR101 |
*
Counterstaining with another marker should be performed
**
SR101 is a rhodamine dye that has been commonly used for labeling astrocytes both in vitro and in vivo. Care must be taken as it is also shown to label oligodendrocytes in longer exposure (Hill & Grutzendler, 2014).