Protein kinase C (PKC) plays a prominent role in immune signaling. To elucidate the signal transduction in a respiratory burst and isoform-specific function of PKC during FcγR-mediated phagocytosis, we used live, digital fluorescence imaging of mouse microglial cells expressing GFP-tagged molecules. βI PKC, εPKC, and diacylglycerol kinase (DGK) β dynamically and transiently accumulated around IgG-opsonized beads (BIgG). Moreover, the accumulation of p47phox, an essential cytosolic component of NADPH oxidase and a substrate for βI PKC, at the phagosomal cup/phagosome was apparent during BIgG ingestion. Superoxide (O2-) production was profoundly inhibited by Gö6976, a cPKC inhibitor, and dramatically increased by the DGK inhibitor, R59949. UItrastractural analysis revealed that BIgG induced O2- production at the phagosome but not at the intracellular granules. We conclude that activation/accumulation of βI PKC is involved in O2- production, and that O2- production is primarily initiated at the phagosomal cup/phagosome. This study also suggests that DGKβ plays a prominent role in regulation of O2- production during FcγR-mediated phagocytosis.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy