초록
Protein kinase C isozymes in a human prostate adenocarcinoma PC-3 cell line were characterized. Immunoreactive bands and immunocytochemical stains were obsenred in PC-3 cells with antibodies raised against protein kinase C ${\alpha}$, ${\beta}$, ${\gamma}$, $\delta$, $\varepsilon$, and ζ types, respectively. Protein kinase C ${\alpha}$ corresponded to a immunoreactive band at a molecular weight of 80,000-dalton, whereas molecular weights of other immunoreactive isozvmes of protein kinase C were detected at 68,000-dalton. Protein kinHse C $\delta$ and ζ antibodies detected additional bands at 55,000-dalton and 80,000-dalton, respectively Immunocvtochemical study confirmed the results of the immunoblotting experiments qualitatively: all six protein kinase C isozymes were detected in the cytoplasm of PC-3 cells. Translocation of protein kinase C in PC-3 cells were also examined with phorbol 12-myristate 13-acetate (PMA), bryostatin 2, diolein, and 1-oleoyl-2-acetyl glycerol (OAG). Differential reactions of protein kinase C isozvmes to these activators were obsenred. When PC-3 cells were treated with 10mM bryostatin 2, protein kinase C isozyme u was translocated into the nucleus, whereas s type was translocated into the plasma membrane and the nucleus. Protein kinase C ${\alpha}$ and ζ types were translocated into the nucleus following the treatment with 101M diolein, whereas protein kinase C ${\alpha}$, ${\beta}$, ${\gamma}$, and $\varepsilon$ types were translocated into the nucleus by the treatment with 10mM OAG. Protein kinase C ${\alpha}$ and $\varepsilon$ types were translocated into the nucleus in the presence of 100nM PMA. Protein kinase C $\delta$ type was translocated to the nuclear membrane by these activators, however, only PMA-induced translocation was inhibited by protein kinase C inhibitor, 1-(5-isoquinolinesulfonyll-2-methvlpiperazine dihvdrochloride (H7) . H7 inhibited translocation of protein kinase C ${\alpha}$ type induced by PMA, ${\beta}$ type by OAG and s type by PMA and OAG, whereas it did not affect translocations induced by bryostatin and diolein, respectively. These results suggest that there exist six isoformes of protein kinase C (${\alpha}$, ${\beta}$, ${\gamma}$, $\delta$, $\varepsilon$ and ζ types) in PC-3 cells and that each of these isozvmes distinctivelv reacts to bryostatin, diolein, OAG and PMA, in part due to an altered molecular size and conceivably discrete binding site(s).