Microfilaments regulate the rate of exocytosis in rat basophilic leukemia cells.
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.
Narasimhan
V
V
Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853.
Holowka
D
D
Baird
B
B
D008841:Actin Cytoskeleton / Q000502:physiology*; D000199:Actins / Q000502:physiology*; D000818:Animals; D000941:Antigens; D001491:Basophils / Q000502:physiology*; D002118:Calcium / Q000502:physiology; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000502:physiology*; D005089:Exocytosis; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D007942:Leukemia, Experimental; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D013301:Streptolysins / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D000199:Actins; D000941:Antigens; D007295:Inositol Phosphates; D013301:Streptolysins; D013873:Thionucleotides; D012701:Serotonin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D003571:Cytochalasin B; D006160:Guanosine Triphosphate; D002118:Calcium