Fig. 2

TAM receptor-mediated efferocytosis. Efferocytosis is the process of using phagocytes to accurately recognize and engulf apoptotic cells. Apoptotic cells send out "find me" signals (e.g., lipids, proteins, and peptides) and "eat me" signals (e.g., PtdSer) to promote the recruitment of phagocytes. PtdSer of the apoptotic cells migrates to the outer leaflet of the plasma membrane during apoptosis, interacting with the bridge ligand Gas6/ProS1 to indirectly bind to TAM receptors on the surface of phagocytes. Subsequently, phosphorylation of TAM receptors activates PI3K/Akt and other downstream signaling pathways, regulates cytoskeletal rearrangements to engulf the apoptotic cells, and leads to M2 macrophages polarization, production of anti-inflammatory cytokines. PtdSer, phosphatidylserine; PI3K/Akt, phosphatidylinositol 3 kinase/protein serine threonine kinase; M2 macrophages, M2-like phenotype of macrophages