Localized exocytosis of primary (lysosomal) granules during phagocytosis: role of Ca2+-dependent tyrosine phosphorylation and microtubules.
The uptake and killing of bacteria by human neutrophils are dependent on the fusion of secretory granules with forming phagosomes. The earliest component of exocytosis was found to precede phagosome closure, so that granular membrane constituents were detectable on the plasmalemma. We show that during phagocytosis of IgG-opsonized particles, this early secretory response is highly polarized in the