FcεRI and Kit signal to actin cytoskeleton via different pathways

Mast cells are key effector cells of the immune system whose exact physiological functions have been the subject of much debate. They have been mentioned mostly as the drivers of allergic and inflammatory reactions via allergens triggering their high affinity receptors for IgE (FcεRI). However, recent findings implicate their important role also in other innate immune functions like host protection from bacterial and viral infections. Agent recognized by surface receptor initialize various intracellular signaling pathways leading to cell response. Thus, better understanding of signal transduction in mast cells is important in development of new therapeutic approaches. Early phases of mast cell activation mediated by FcεRI and/or Kit, a receptor for stem cell factor (SCF), involve phosphorylation of the transmembrane adaptor protein Non-T cell activation linker (NTAL) and mast cell spreading. Morphological studies of mast cells derived from bone marrow of mice deficient in NTAL (NTAL knock out, NTAL -/-) revealed markedly reduced spreading on fibronectin after stimulation with antigen (Ag) alone or in combination with SCF, when compared to wild type (WT) cells. Subsequent quantification of cell area and analysis of other mophological parameters confirmed these observations. Mast cell activation was..