[The involvement of protein kinase C isozymes in activation of phospholipase D and secretion of serotonin in rat basophilic leukemia cells].
Western blot analysis shows the presence of protein kinase C (PKC) alpha, beta1, beta2, delta, epsilon, zeta isozymes in rat basophilic leukemia (RBL-2H3) cells. Antigen stimulation caused preferential translocation of protein kinase C (PKC) delta and epsilon to membranes. On the other hand, when the cells were stimulated by phorbol 12-myristate 13-acetate (PMA) or ionophore (A23187), PKCalpha and beta were predominantly translocated. Phospholipase D (PLD) was activated by three stimulants in order: A23187 > PMA >> antigen. Therefore, PKCalpha and beta seem to be involved in the activation of PLD in RBL cells. The translocation of all PKC isozymes in A23187 stimulation was weak. Therefore, PLD activation in A23187 stimulation may require some other factors than PKC which are associated with the increase of Ca2+ in the cells. The cells stimulated by antigen secreted serotonin to the same level as the cells stimulated by A23187. In both stimulation, PKCalpha and epsilon were translocated to almost similar level, suggesting that PKCalpha and epsilon are involved in the secretion. All PKC isozymes except zeta were markedly translocated in PMA stimulation, but secretion did not occur. These results indicate that translocation of PKC alpha and beta may be associated with PLD activation and also that both translocation of PKCalpha and epsilon and intracellular calcium increase are required for serotonin secretion in RBL cells.
Ojio
K
K
Department of Otolaryngology, Gifu University School of Medicine.
Nakamura
Y
Y
Miyata
H
H
Banno
Y
Y
Nakashima
S
S
Nozawa
Y
Y
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004789:Enzyme Activation; D007476:Ionophores / Q000494:pharmacology; D007527:Isoenzymes / Q000502:physiology*; D015471:Leukemia, Basophilic, Acute / Q000201:enzymology; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007476:Ionophores; D007527:Isoenzymes; D012701:Serotonin; D000001:Calcimycin; D011493:Protein Kinase C; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium