Induction of tyrosine phosphorylated proteins in THP-1 cells by Salmonellatyphimurium, Pasteurella haemolytica and Haemophilus influenzae porins

The effect of porins purified from Salmonella typhimurium, Pasteurella haem olytica and Haemophilus influenzae on induction of tyrosine phosphorylation in THP-1 cells and C3H/HeJ macrophage was investigated. Incubation of pori ns at concentration of 1.0-5.0 mug ml(-1) with either THP-1 or macrophage f rom C3H/HeJ mice resulted in tyrosine phosphorylation of specific host cell proteins. After porin stimulation a pattern of tyrosine phosphorylated pro teins appeared in the soluble cytoplasmic fraction, in the membrane fractio n and in the insoluble protein fraction. The observed effects were dependen t on the porin concentrations; they reached a maximal expression at 3 min a nd declined at 60 min. Porin and lipopolysaccharide treatments induce a sim ilar phosphorylation pattern in all of the three cellular fractions studied . A difference can be observed in the cytoplasmic fraction bands of 50-60 k Da, which are more evident after treatment with lipopolysaccharide, and in the insoluble fraction band of 80 kDa and the cytoplasmic fraction band of 250 kDa, which are more evident after treatment with porins. The events of tyrosine protein phosphorylation were present in macrophage from lipopolysa ccaride-hyporesponsive C3H/HeJ mice stimulated with porins, while they were markedly reduced when the cells were stimulated with lipopolysaccharide. S taurosporine, genistein and cytochalasin D induced in the three cellular fr actions a different inhibition pattern of tyrosine protein phosphorylation. in porin stimulated cells. Porins extracted from the three bacterial speci es investigated behave in a similar way as stimuli more or less potent; Hib porin seems to be the most powerful stimulator and, moreover, it specifica lly induces phosphorylation of a 55 kDa band. (C) 2001 Federation of Europe an Microbiological Societies. Published by Elsevier Science BN. All rights reserved.