Abstract
To investigate the possible involvement of cytoskeletal components in antigen (Ag)-mediated activation of phospholipase D (PLD) in rat basophilic leukemia (RBL-2H3) cells, the effects of cytochalasin D, which is known to interfere with actin organization in various cells, on Ag-induced PLD activity were examined. Cytochalasin D, at concentrations that induced distinct shape changes of RBL-2H3 cells, enhanced the Ag-induced 5-HT (serotonin) release and formation of phosphatidylbutanol (PBut), a specific and stable metabolite produced by PLD activity in a concentration-dependent manner. Concomitantly, Ag-induced 1,2-diacylglycerol (DG) accumulation as well as phosphatidic acid (PA) production were increased by the drug. In contrast, cytochalasin D had no effect on PLD activation in response to phorbolmyristate acetate, an activator of protein kinase C (PKC), and Ca2+ ionophore A23187. These results suggest that cytoskeletal components may modulate Ag-induced PLD activation upstream of PKC and Ca2+ in RBL-2H3 cells.
