scholarly journals Possible involvement of GTP-binding protein in the mechanism for Ca2+-dependent exocytosis in adrenal chromaffin cells

1990 ◽  
Vol 52 ◽  
pp. 198
Author(s):  
Mica Ohara-Imaizumi ◽  
Kyoko Takeda ◽  
Nobuyuki Kawae ◽  
Konosuke Kumakura
Keyword(s):  
Chromaffin Cells ◽  
Binding Protein ◽  
Adrenal Chromaffin Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Adrenal Chromaffin

scholarly journals Stimulation of Ca2+-independent catecholamine secretion from digitonin-permeabilized bovine adrenal chromaffin cells by guanine nucleotide analogues. Relationship to arachidonate release

1990 ◽  
Vol 269 (2) ◽  
pp. 521-526 ◽  
Author(s):  
A Morgan ◽  
R D Burgoyne
Keyword(s):  
Arachidonic Acid ◽  
Chromaffin Cells ◽  
Binding Protein ◽  
Catecholamine Secretion ◽  
Arachidonic Acid Release ◽  
Adrenal Chromaffin Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Acid Release ◽  
Adrenal Chromaffin

The effect of GTP analogues on catecholamine secretion and [3H]arachidonic acid release from digitonin-permeabilized adrenal chromaffin cells was examined. Several GTP analogues stimulated Ca2(+)-independent exocytosis, with the order of efficacy being XTP greater than ITP greater than guanosine 5′-[beta gamma-imido]triphosphate (p[NH]ppG) greater than guanosine 5′-[gamma-thio]triphosphate (GTP[S]). The stimulatory effect of the GTP analogues appeared to be due to activation of a conventional GTP-binding protein, as it was inhibited by guanosine 5′-[beta-thio]diphosphate (GDP[S]). In contrast, Ca2(+)-dependent exocytosis was only partially inhibited by high doses of GDP[S]. GTP did not stimulate Ca2(+)-independent exocytosis, but instead was found to inhibit secretion caused by micromolar Ca2+. Arachidonic acid (100 microM) also stimulated Ca2(+)-independent catecholamine secretion. Determination of the effect of GTP analogues on release of free [3H]arachidonic acid into the medium showed that it was stimulated by GTP[S] but inhibited by GTP, p[NH]ppG, ITP and XTP. The inhibition of [3H]arachidonic acid release by XTP was not prevented by GDP[S]. These results demonstrate that activation of a GTP-binding protein by certain GTP analogues can induce Ca2(+)-independent secretion in adrenal chromaffin cells and that the effect of GTP analogues on Ca2(+)-independent secretion can be dissociated from generation of arachidonic acid.

Regulatory Role of the GTP-Binding Protein, Go, in the Mechanism of Exocytosis in Adrenal Chromaffin Cells

1992 ◽  
Vol 58 (6) ◽  
pp. 2275-2284 ◽  
Author(s):  
Mica Ohara-Imaizumi ◽  
Kimihiko Kameyama ◽  
Nobuyuki Kawae ◽  
Kyoko Takeda ◽  
Shun Muramatsu ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Binding Protein ◽  
Regulatory Role ◽  
Adrenal Chromaffin Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Adrenal Chromaffin

scholarly journals Inhibition of prostaglandin E2-induced phosphoinositide metabolism by phorbol ester in bovine adrenal chromaffin cells

1988 ◽  
Vol 255 (3) ◽  
pp. 957-962 ◽  
Author(s):  
H Yokohama ◽  
M Negishi ◽  
K Sugama ◽  
H Hayashi ◽  
S Ito ◽  
...  
Keyword(s):  
Prostaglandin E2 ◽  
Phorbol Ester ◽  
Chromaffin Cells ◽  
Inositol Phosphates ◽  
Phosphoinositide Metabolism ◽  
Adrenal Chromaffin Cells ◽  
Gtp Binding Protein ◽  
Intact Cells ◽  
Gtp Binding ◽  
Adrenal Chromaffin

In bovine adrenal chromaffin cells, prostaglandin E2 (PGE2) stimulates the formation of inositol phosphates and Ca2+ mobilization through its specific receptor [Yokohama, Tanaka, Ito, Negishi, Hayashi & Hayaishi (1988) J. Biol. Chem. 263, 1119-1122]. Here we show that PGE2-induced phosphoinositide metabolism was blocked by pretreatment with 12-O-tetradecanoylphorbol 13-acetate (TPA). Using intact cells, we also examined the inhibitory effect of TPA on the individual steps of the activation process of phosphoinositide metabolism. The inhibition was observed within 1 min and complete by 10 min after addition of 1 microM-TPA, and half-maximal inhibition by TPA occurred at 20 nM. TPA prevented Ca2+ mobilization induced by PGE2, but not by the Ca2+ ionophore ionomycin. The inactive phorbol ester 4 alpha-phorbol 12,13-didecanoate did not inhibit the formation of inositol phosphates and Ca2+ mobilization by PGE2. TPA treatment affected neither the high-affinity binding of [3H]PGE2 to intact cells and membrane fractions nor the ability of guanosine 5′-[gamma-thio]triphosphate to decrease the binding in membrane fractions. TPA also abolished phosphoinositide metabolism induced by muscarinic-receptor activation. NaF plus AlCl3 and ionomycin caused the accumulation of inositol phosphates, probably by directly activating a GTP-binding protein(s) and phospholipase C respectively; neither accumulation was inhibited by TPA treatment. These results suggest that protein kinase C serves as a feedback regulator for PGE2-induced phosphoinositide metabolism. The site of action of TPA appears to be distal to the coupling of the receptor to GTP-binding protein, but on a component(s) specific to the agonist-induced phosphoinositide metabolism.

scholarly journals Regulation of Ca2+ channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

2016 ◽  
Vol 27 (21) ◽  
pp. 3329-3341 ◽  
Author(s):  
Trine Lisberg Toft-Bertelsen ◽  
Iwona Ziomkiewicz ◽  
Sébastien Houy ◽  
Paulo S. Pinheiro ◽  
Jakob B. Sørensen
Keyword(s):  
Plasma Membrane ◽  
Chromaffin Cells ◽  
Botulinum Neurotoxin ◽  
Binding Protein ◽  
Expression Level ◽  
Cholesterol Depletion ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
Ca2 Channels

SNAP-25 regulates Ca2+ channels, with potentially important consequences for diseases involving an aberrant SNAP-25 expression level. How this regulation is executed mechanistically remains unknown. We investigated this question in mouse adrenal chromaffin cells and found that SNAP-25 inhibits Ca2+ currents, with the B-isoform being more potent than the A-isoform, but not when syntaxin-1 is cleaved by botulinum neurotoxin C. In contrast, syntaxin-1 inhibits Ca2+ currents independently of SNAP-25. Further experiments using immunostaining showed that endogenous or exogenous SNAP-25 expression recruits syntaxin-1 from clusters on the plasma membrane, thereby increasing the immunoavailability of syntaxin-1 and leading indirectly to Ca2+ current inhibition. Expression of Munc18-1, which recruits syntaxin-1 within the exocytotic pathway, does not modulate Ca2+ channels, whereas overexpression of the syntaxin-binding protein Doc2B or ubMunc13-2 increases syntaxin-1 immunoavailability and concomitantly down-regulates Ca2+ currents. Similar findings were obtained upon chemical cholesterol depletion, leading directly to syntaxin-1 cluster dispersal and Ca2+ current inhibition. We conclude that clustering of syntaxin-1 allows the cell to maintain a high syntaxin-1 expression level without compromising Ca2+ influx, and recruitment of syntaxin-1 from clusters by SNAP-25 expression makes it available for regulating Ca2+ channels. This mechanism potentially allows the cell to regulate Ca2+ influx by expanding or contracting syntaxin-1 clusters.

scholarly journals Association of the GTP-binding protein Rab3A with bovine adrenal chromaffin granules.

1990 ◽  
Vol 87 (15) ◽  
pp. 5692-5696 ◽  
Author(s):  
F. Darchen ◽  
A. Zahraoui ◽  
F. Hammel ◽  
M. P. Monteils ◽  
A. Tavitian ◽  
...  
Keyword(s):  
Binding Protein ◽  
Chromaffin Granules ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Adrenal Chromaffin

scholarly journals Exocytosis in chromaffin cells. Possible involvement of the heterotrimeric GTP-binding protein G(o)

1993 ◽  
Vol 268 (20) ◽  
pp. 14715-14723
Author(s):  
N. Vitale ◽  
H. Mukai ◽  
B. Rouot ◽  
D. Thiersé ◽  
D. Aunis ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Binding Protein ◽  
Protein G ◽  
Gtp Binding Protein ◽  
Gtp Binding
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