The role of GTP-binding proteins (G-proteins) in the secretory process in chromaffin cells was investigated by studying the effects of pertussis toxin (PTX) on catecholamine release and generation of various second messengers. PTX was found to stimulate the catecholamine secretion induced by nicotine, 59 mM-K+ or veratridine. PTX also potentiated Ca2(+)-evoked catecholamine release from permeabilized chromaffin cells, suggesting that PTX substrate(s) regulate the exocytotic machinery at a step distal to the rise in intracellular Ca2+. We have investigated the possible intracellular pathways involved in the stimulation of secretion by PTX. PTX did not modify the translocation of protein kinase C (PKC) to membranes in intact or permeabilized cells; in addition, neither inhibitors nor activators of PKC had any effect on catecholamine release induced by PTX. Thus it seems unlikely that the effect of PTX on secretion is mediated by activation of PKC. The effect of PTX is also cyclic AMP-independent, as PTX did not change cytoplasmic cyclic AMP levels. The relationship between PTX treatment and arachidonic acid release was also examined. We found that an increase in cytoplasmic arachidonic acid concentration enhanced Ca2(+)-evoked catecholamine release in permeabilized cells, but arachidonic acid did not mimic the effect of PTX on the Ca2(+)-dose-response curve for secretion. Furthermore, PTX did not significantly modify the release of arachidonic acid measured in resting or stimulated chromaffin cells, suggesting that the stimulatory effect of PTX on secretion is not mediated by an activation of phospholipase A2. Taken together, these results suggest that PTX may modulate the intracellular machinery of secretion at a step distal to the generation of second messengers. In alpha-toxin-permeabilized cells, full retention of the PTX-induced activation of secretion was observed even 30 min after permeabilization. In contrast, when chromaffin cells were permeabilized with streptolysin-O (SLO), there was a marked progressive loss of the PTX effect. We found that SLO caused the rapid leakage of three G-protein alpha-subunits which are specifically ADP-ribosylated by PTX. We propose that a PTX-sensitive G-protein may play an inhibitory role in the final stages of the Ca2(+)-evoked secretory process in chromaffin cells.
Skip Nav Destination
Close
Article navigation
March 1991
- Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
March 01 1991
A pertussis-toxin-sensitive protein controls exocytosis in chromaffin cells at a step distal to the generation of second messengers
J M Sontag
;
J M Sontag
*Unité INSERM U-338 de Biologie, de la Communication Cellulaire, 5 rue Blaise Pascal, 6708 Strasbourg, Cedex
Search for other works by this author on:
D Thierse
;
D Thierse
*Unité INSERM U-338 de Biologie, de la Communication Cellulaire, 5 rue Blaise Pascal, 6708 Strasbourg, Cedex
Search for other works by this author on:
B Rouot
;
B Rouot
†C.C.I.P.E., rue de la Cardonille, 34094 Montpellier, Franc
Search for other works by this author on:
D Aunis
;
D Aunis
*Unité INSERM U-338 de Biologie, de la Communication Cellulaire, 5 rue Blaise Pascal, 6708 Strasbourg, Cedex
Search for other works by this author on:
M F Bader
M F Bader
*Unité INSERM U-338 de Biologie, de la Communication Cellulaire, 5 rue Blaise Pascal, 6708 Strasbourg, Cedex
Search for other works by this author on:
Biochem J (1991) 274 (2): 339–347.
Citation
J M Sontag, D Thierse, B Rouot, D Aunis, M F Bader; A pertussis-toxin-sensitive protein controls exocytosis in chromaffin cells at a step distal to the generation of second messengers. Biochem J 1 March 1991; 274 (2): 339–347. doi: https://doi.org/10.1042/bj2740339
Download citation file:
Close
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Biochemical Society Member Sign in
Sign InSign in via your Institution
Sign in via your InstitutionGet Access To This Article
Cited By
Related Articles
Lack of ceramide generation and altered sphingolipid composition are associated with drug resistance in human ovarian carcinoma cells
Biochem J (March,2006)
Circular RNA circ-PVT1 contributes to paclitaxel resistance of gastric cancer cells through the regulation of ZEB1 expression by sponging miR-124-3p
Biosci Rep (December,2019)