Protein kinase C activation in B cells by indolactam inhibits anti-Ig-mediated phosphatidylinositol bisphosphate hydrolysis but not B cell proliferation
| Autor: | Mond, J. J., ANIL BALAPURE, Feuerstein, N., June, C. H., Brunswick, M., Lindsberg, M. -L, Witherspoon, K. |
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| Rok vydání: | 1990 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1550-6606 0022-1767 |
| Popis: | In order to examine the role of phosphatidylinositol bisphosphate (PIP2) hydrolysis in B cell activation, we studied the effect of various classes of protein kinase C (PKC) activators on anti-Ig-mediated B cell stimulation. Anti-Ig-stimulated PIP2 hydrolysis, elevations in [Ca2+]i, and induction of DNA synthesis were inhibited by PMA (a phorbol ester) as previously reported. In contrast, indolactam (an alkaloid PKC activator) inhibited PIP2 hydrolysis and elevations in [Ca2+]i, but stimulated rather than inhibited cellular proliferation. In order to examine whether the binding avidity of the PKC activators to PKC played a role in determining their activity to stimulate or inhibit B cell activation, we studied two other PKC activators, bryostatin and mezerein. Again, both inhibited anti-Ig mediated PIP2 hydrolysis and elevations in [Ca2+]i, whereas only the former inhibited induction of DNA synthesis. These data suggest that a) high levels of PIP2 hydrolysis and elevations in [Ca2+]i are not essential for anti-Ig-mediated induction of B cell DNA synthesis and b) activation of PKC may induce both stimulatory and inhibitory pathways of B cell activation, and whether stimulation or inhibition of cell activation is observed may depend on the combined intensity of these two signals. |
| Databáze: | OpenAIRE |
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