FIGURE 4.

Phosphatidylserine (PS) is involved in microglia-mediated neuron apoptosis. When the neuron is undergoing apoptosis, PS is exposed to the cell surface. Microglia can find and phagocyte the apoptotic neuron. Several PS effectors expressed in microglia can recognize the exposed PS directly or indirectly. TREM2, RAGE, TIM4, and BAI1 can bind PS directly. TAM receptors recognize PS indirectly through their ligands Gas6 and ProS1. Both Gas6 and ProS1 have Gla-domain to bind PS. As well as TAM receptor, intergrinαvβ3 recognize PS through MFG-E8. All of the PS effectors can trigger cytoskeletal rearrangement of microglia and engulf the dying neuron. Created with BioRender.com.