Mechanisms of G protein-coupled receptor-mediated degranulation.

Mast cells and neutrophils play a major role in the innate immune response. Following invasion of the host by microorganisms, these immune cells become activated and release anti-microbial cytotoxic granules in an effort to destroy invading microorganisms in a process termed degranulation. By-products from the degradation of microorganisms can also activate G-protein-coupled receptors (GPCRs), which can further activate immune cells. While degranulation of basophils has been extensively characterized for IgE receptors, the signaling pathways initiated by GPCRs that lead to degranulation and the regulation of these pathways during the degranulation response are areas of active study. This review summarizes the current understanding of the mechanisms involved in the regulation of degranulation through GPCRs.