Biologjia Online

Listeria monocytogenes causes a variety of diseases, the most severe being meningoencephalitis. The bacterium is phagocytosed into cells and multiplies after escaping from the phagolysosomes. It then moves to the plasma membrane and forms a filopod that is ingested by an adjacent cell, and the cycle is repeated. Actin assembly is essential for the movement of the bacteria through the cytoplasm and formation of the filopod. Generally, in motile non-muscle cells, an accumulation of phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3), converted from phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), is associated with the formation of new actin filaments. It is known that ActA, the bacterial surface protein that induces actin assembly, can bind to both PtdIns(4,5)P2 and PtdIns(3,4,5)P3, but the physiological significance of the inositide binding site has not been examined.