Phosphoinositides and phagocytosis

Phosphoinositide 3 kinases (PI3Ks)* are known as regulators of phagocytosis . Recent results demonstrate that class I and III PI3Ks act consecutively i n phagosome formation and maturation, and that their respective products, p hosphatidylinositol 3,4,5-trisphosphate (PI[3,4,5]P-3) and phosphatidylinos itol 3-phosphate (PI[3]P), accumulate transiently at different stages. Phag osomes containing Mycobacterium tuberculosis do not acquire the PI(3)P-bind ing protein EEA1, which is required for phagosome maturation. This suggests a possible mechanism of how this microorganism evades degradation in phago lysosomes.