Abstract
During phagocytic uptake by macrophages, role of Golgi apparatus or vesicles derived from it has never been established. Using fluorescently tagged Mannosidase-II, a marker for Golgi-derived vesicles, we show these vesicles are recruited during uptake of diverse targets including latex beads, E. coli, Salmonella Typhimurium and Mycobacterium tuberculosis in both human and mouse macrophages. The recruitment of Mannosidase-II vesicles occurred very early during phagocytosis, which was mediated by focal exocytosis. The focal movement of Mannosidase-II vesicles required Ca2+ from both extra-and intra-cellular sources apart from PI3Kinase, microtubules and dynamin-2. At the site of uptake voltage-gated Ca2+ channels help establish a Ca2+-dependent local PIP3 gradient, which guide the focal movement. Mannosidase-II vesicles also contained Neuronal Calcium Sensor-1 (NCS1) and resembled secretory vesicles. Depleting NCS1 blocked the recruitment of Mannosidase-II vesicles and inhibited phagocytic uptake of diverse targets. We propose Golgi-derived vesicles provide membrane for phagosome biogenesis and are universally required for phagocytosis, the key innate defense function.
Footnotes
↵$ Equal contribution