PORPHYROMONAS-GINGIVALIS FIMBRIAE INDUCE A 68-KILODALTON PHOSPHORYLATED PROTEIN IN MACROPHAGES

The present study was performed to examine whether Porphyromonas gingi valis fimbriae induce specifically a protein kinase-mediated phosphory lated protein that is involved in the mechanism of signal transduction . The fimbriae induced a 68-kDa phosphorylated protein (pp68) in a dos e-dependent manner in mouse peritoneal macrophages. A marked appearanc e of pp68 was observed 20 min after the initiation of fimbrial treatme nt. The fimbria-induced pp68 was inhibited dramatically by staurospori ne, a potent inhibitor of protein kinase C. pp68 induction was also in hibited by H-7, a potent inhibitor of several types of protein kinase. However, the induction was not inhibited by HA-1004 and H-8, relative ly high-affinity inhibitors of protein kinase A. Phorbol myristate ace tate and 1-oleoyl-2-acetyl-sn-glycerol, activators of protein kinase C , were able to induce pp68 in mouse peritoneal macrophages. This prote in was localized in the cytosolic fraction of fimbria-treated macropha ges. pp68 also was induced in fimbria-treated human monocyte-like cell s, Finally, we observed that gene expression of the fimbria-induced ne utrophil chemoattractant KC was inhibited markedly by staurosporine.