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Updated: Aug 9, 2026

Investigating Mast Cell Secretory Granules; from Biosynthesis to Exocytosis
Published on: January 26, 2015
Microfilaments regulate the rate of exocytosis in rat basophilic leukemia cells
V Narasimhan1, D Holowka, B Baird
1Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
Abstract:
Disruption of microfilaments in rat basophilic leukemia (RBL) cells by exposure to cytochalasin B is observed to potentiate the rate of antigen-stimulated secretion from these cells. Under these conditions, cytochalasin B is without effect on the antigen-stimulated production of inositol phosphates or 45Ca2(+)-influx. In streptolysin-O-permeabilized RBL cells, cytochalasin B is observed to potentiate the rate of secretion in response both to guanosine 5'-(2-thio)-O-triphosphate (GTP gamma S) and to Ca2+ (buffered between 0.1 and 10 microM). However, under these conditions, cytochalasin B does not affect to antigen-stimulated production of inositol phosphates. Consistent with these data, microfilaments are proposed to regulate a terminal step in exocytosis, in a physiologically relevant manner.
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