Protein kinase C activation in B cells by indolactam inhibits anti-Ig-mediated phosphatidylinositol bisphosphate hydrolysis but not B cell proliferation.
J Immunol
; 144(2): 451-5, 1990 Jan 15.
Article
in En
| MEDLINE
| ID: mdl-2153169
ABSTRACT
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.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Kinase C
/
B-Lymphocytes
/
Lymphocyte Activation
/
Diterpenes
/
Indoles
/
Lactams
Limits:
Animals
Language:
En
Journal:
J Immunol
Year:
1990
Document type:
Article