Fc epsilon receptor mediated Ca2+ influx into mast cells is modulated by the concentration of cytosolic free Ca2+ ions.
The relationship between the Fc epsilon receptor mediated stimulation of mast cells and the Ca2+ signal it induces were studied using thapsigargin (TG), a blocker of the endoplasmic reticulum Ca2+ pump. TG induced, in mucosal mast cells (RBL-2H3 line), a dose-dependent and an InsP3-independent increase in [Ca2+]i (from resting levels of 83-150 nM to 600-680 nM), and a secretory response amounting to 30-50% of that observed upon Fc epsilon RI clustering. The TG induced rise of [Ca2+]i is most probably provided by both arrest of its uptake by the endoplasmic reticulum and influx from the medium. Thus, Ca2+ influx in mast cells may be modulated by the [Ca2+]i level.
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Department of Chemical Immunology, Weizmann Institute of Science, Rehovot Israel.
Pecht
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D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent; D003600:Cytosol / Q000378:metabolism*; D007073:Immunoglobulin E / Q000378:metabolism*; D007295:Inositol Phosphates / Q000096:biosynthesis; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017455:Receptors, IgE / Q000378:metabolism*; D015398:Signal Transduction; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D002413:Cations, Divalent; D007295:Inositol Phosphates; D017455:Receptors, IgE; D013729:Terpenes; D007073:Immunoglobulin E; D019284:Thapsigargin; D002118:Calcium