Fig. 1

Phosphoinositide signaling cascade regulates actin remodeling and phagocytosis. In normal cells, during phagocytosis the related actin remodeling modulated by different PI species. In initial stages of phagocytosis, PI 4,5-P2 concentration increases via PIP5K, which initiates actin polymerization to extend pseudopod to catch the target. Once the target is attached to cell membrane for the process of sealing and engulfment PI 3,4, 5-P3 concentration increases via PI3K at phagosome. In the processes of phagosome maturation through early endosome, PI 3,4-P2 synthesized via SHIP and PI3P regulates trafficking. At the later stages for late endosome and lysosome mediated trafficking PI 3,5-P2 synthesized via PIKfyve. The PI 4, 5-P2 activates the ARP2/3-mediated actin polymerization via direct interaction with Rac and WASP family proteins. PI 4, 5-P2 inhibit the proteins that enhance depolymerization or inhibition of actin polymerization