FOCAL POINT (L-R) Tony Yeung, lead author. Phagosomes (circles) maintain a significant negative charge on their surface membranes (green) despite loss of phosphoinositide (red). This persistence of charge is due to the presence of phosphatidylserine. Phagosomes lose their phosphatidylserine and thus their charge, however, if they contain pathogens such as Legionella and Chlamydia. These bugs direct phagosomes away from their normal lysosome fate to alternative safe cellular destinations.