FceRI cross-linking-induced actin assembly mediates calcium signalling in RBL-2H3 mast cells
نویسندگان
چکیده
1 To determine the role of actin assembly in the Ca signalling of mast cells activated by crosslinking of FceRI, we examined the eects of cytochalasin D, an inhibitor of actin polymerization. 2 In the RBL-2H3 cells, F-actin content was increased by sensitization with anti-dinitrophenol (DNP) IgE. In these cells, cytochalasin D induced oscillatory increases in cytosolic Ca ([Ca]i); these increase were inhibited by jasplakinolide, a stabilizer of actin ®laments. 3 In the IgE-sensitized RBL-2H3 cells, DNP-human serum albumin (DNP-HSA) augmented actin assembly. DNP-HSA also increased the production of IP3, [Ca ]i and degranulation. Cytochalasin D enhanced all of these DNP-HSA-induced eects. 4 In a Ca-free solution, DNP-HSA induced a transient increase in [Ca]i, and this increase was accelerated by cytochalasin D. After cessation of the DNP-HSA-induced Ca release, the readdition of Ca induced a sustained increase in [Ca]i through capacitative Ca 2+ entry (CCE), and this increase was enhanced by cytochalasin D. 5 The eect of cytochalasin D in enhancing the CCE activity was prevented by xestospongin C. 6 In contrast, neither the Ca release nor the CCE activation that was induced by thapsigargin was aected by cytochalasin D. 7 These results suggest that actin de-polymerization stimulates the FceRI-mediated signalling to augment the release of Ca from the endoplasmic reticulum in RBL-2H3 cells. British Journal of Pharmacology (2002) 136, 837 ± 846
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