scholarly journals Synaptotagmin-7 endows a population of chromaffin cell vesicles with enhanced calcium sensing and delayed content release properties

2019 ◽  
Author(s):  
M Bendahmane ◽  
AJB Kreutzberger ◽  
A Chapman-Morales ◽  
J Philippe ◽  
N Schenk ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Physiological Role ◽  
Calcium Sensitivity ◽  
Vesicle Fusion ◽  
Adrenal Chromaffin Cells ◽  
Supported Bilayers ◽  
Calcium Sensors ◽  
Calcium Sensing ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

Synaptotagmin-7 (Syt-7) is one of two major calcium sensors for exocytosis in adrenal chromaffin cells, the other being synaptotagmin-1 (Syt-1). Despite its undoubted importance, questions remain as to the functional and physiological role of Syt-7 in secretion. We examined this issue using two distinct preparations - mouse chromaffin cells lacking endogenous Syt-7 (KO cells) and a reconstituted system employing cell-derived vesicles expressing either Syt-7 or Syt-1. First, we report using immunofluorescence that Syt-7 exhibits a punctate intracellular distribution consistent with its sorting to organelles, including dense core vesicles. We also find that the likelihood of vesicle fusion in KO cells is markedly lower than in WT cells. When fusion does occur, cargoes are discharged more rapidly when only Syt-1 is available to facilitate release. A distinctive characteristic of KO cells is that secretion runs down after prolonged cholinergic stimulation. In contrast, exocytosis persists in WT cells even with extended exposure to acetylcholine, suggesting a key role for Syt-7 in sustaining the secretory response. To determine the extent to which the aforementioned results are attributable purely to Syt-7, vesicles expressing only Syt-7 or Syt-1 were triggered to fuse on planar supported bilayers bearing plasma membrane SNARE proteins. Here, as in cells, Syt-7 confers substantially greater calcium sensitivity to vesicle fusion than Syt-1 and slows the rate at which cargos are released. Overall, this study demonstrates that by virtue of its high affinity for calcium, Syt-7 plays a central role in regulating secretory output from adrenal chromaffin cells.

scholarly journals Differential Co-release of Two Neurotransmitters from a Vesicle Fusion Pore in Mammalian Adrenal Chromaffin Cells

Neuron ◽  
2019 ◽  
Vol 102 (1) ◽  
pp. 173-183.e4 ◽  
Author(s):  
Quanfeng Zhang ◽  
Bin Liu ◽  
Qihui Wu ◽  
Bing Liu ◽  
Yinglin Li ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Vesicle Fusion ◽  
Fusion Pore ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin

scholarly journals Synaptotagmin-1 and Complexin-2 Work Cooperatively to Promote Exocytosis from Adrenal Chromaffin Cells

2010 ◽  
Vol 98 (3) ◽  
pp. 679a
Author(s):  
Chad P. Grabner ◽  
Gustavo Guzman ◽  
Paanteha Kamalimoghadam ◽  
Yvonne Schwarz ◽  
Dieter Bruns
Keyword(s):  
Chromaffin Cells ◽  
Adrenal Chromaffin Cells ◽  
Complexin 2 ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

scholarly journals Phosphatidylinositol 4,5-bisphosphate optical uncaging potentiates exocytosis

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Alexander M Walter ◽  
Rainer Müller ◽  
Bassam Tawfik ◽  
Keimpe DB Wierda ◽  
Paulo S Pinheiro ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Effector Proteins ◽  
Adrenal Chromaffin Cells ◽  
Cellular Processes ◽  
Inactive Form ◽  
Signaling Lipids ◽  
Electrophysiological Measurements ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

Phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] is essential for exocytosis. Classical ways of manipulating PI(4,5)P2 levels are slower than its metabolism, making it difficult to distinguish effects of PI(4,5)P2 from those of its metabolites. We developed a membrane-permeant, photoactivatable PI(4,5)P2, which is loaded into cells in an inactive form and activated by light, allowing sub-second increases in PI(4,5)P2 levels. By combining this compound with electrophysiological measurements in mouse adrenal chromaffin cells, we show that PI(4,5)P2 uncaging potentiates exocytosis and identify synaptotagmin-1 (the Ca2+ sensor for exocytosis) and Munc13-2 (a vesicle priming protein) as the relevant effector proteins. PI(4,5)P2 activation of exocytosis did not depend on the PI(4,5)P2-binding CAPS-proteins, suggesting that PI(4,5)P2 uncaging may bypass CAPS-function. Finally, PI(4,5)P2 uncaging triggered the rapid fusion of a subset of readily-releasable vesicles, revealing a rapid role of PI(4,5)P2 in fusion triggering. Thus, optical uncaging of signaling lipids can uncover their rapid effects on cellular processes and identify lipid effectors.

scholarly journals Synaptotagmin-1 and -7 are functionally overlapping Ca2+ sensors for exocytosis in adrenal chromaffin cells

2008 ◽  
Vol 105 (10) ◽  
pp. 3998-4003 ◽  
Author(s):  
J.-S. Schonn ◽  
A. Maximov ◽  
Y. Lao ◽  
T. C. Sudhof ◽  
J. B. Sorensen
Keyword(s):  
Chromaffin Cells ◽  
Adrenal Chromaffin Cells ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

Muscarinic receptors in adrenal chromaffin cells: physiological role and regulation of ion channels

2017 ◽  
Vol 470 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Masumi Inoue ◽  
Hidetada Matsuoka ◽  
Keita Harada ◽  
Lung-Sen Kao
Keyword(s):  
Ion Channels ◽  
Muscarinic Receptors ◽  
Chromaffin Cells ◽  
Physiological Role ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin

Differential distribution of synaptotagmin-1, -4, -7, and -9 in rat adrenal chromaffin cells

2011 ◽  
Vol 344 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Hidetada Matsuoka ◽  
Keita Harada ◽  
Jun Nakamura ◽  
Mitsunori Fukuda ◽  
Masumi Inoue
Keyword(s):  
Chromaffin Cells ◽  
Adrenal Chromaffin Cells ◽  
Differential Distribution ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

Delay in vesicle fusion revealed by electrochemical monitoring of single secretory events in adrenal chromaffin cells

Nature ◽  
1992 ◽  
Vol 356 (6364) ◽  
pp. 60-63 ◽  
Author(s):  
Robert H. Chow ◽  
Ludolf von Rüden ◽  
Erwin Neher
Keyword(s):  
Chromaffin Cells ◽  
Vesicle Fusion ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
Electrochemical Monitoring

scholarly journals Doc2B acts as a calcium sensor for vesicle priming requiring synaptotagmin-1, Munc13-2 and SNAREs

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sébastien Houy ◽  
Alexander J Groffen ◽  
Iwona Ziomkiewicz ◽  
Matthijs Verhage ◽  
Paulo S Pinheiro ◽  
...  
Keyword(s):  
Binding Sites ◽  
Chromaffin Cells ◽  
Protein Domain ◽  
Calcium Sensor ◽  
Adrenal Chromaffin Cells ◽  
Dynein Light Chain ◽  
C2 Domains ◽  
Calcium Dependent ◽  
Synaptotagmin 1 ◽  
Adrenal Chromaffin

Doc2B is a cytosolic protein with binding sites for Munc13 and Tctex-1 (dynein light chain), and two C2-domains that bind to phospholipids, Ca2+ and SNAREs. Whether Doc2B functions as a calcium sensor akin to synaptotagmins, or in other calcium-independent or calcium-dependent capacities is debated. We here show by mutation and overexpression that Doc2B plays distinct roles in two sequential priming steps in mouse adrenal chromaffin cells. Mutating Ca2+-coordinating aspartates in the C2A-domain localizes Doc2B permanently at the plasma membrane, and renders an upstream priming step Ca2+-independent, whereas a separate function in downstream priming depends on SNARE-binding, Ca2+-binding to the C2B-domain of Doc2B, interaction with ubMunc13-2 and the presence of synaptotagmin-1. Another function of Doc2B – inhibition of release during sustained calcium elevations – depends on an overlapping protein domain (the MID-domain), but is separate from its Ca2+-dependent priming function. We conclude that Doc2B acts as a vesicle priming protein.

Morphological Observations on the Granule Types in Rabbit Extra-Adrenal Chromaffin Cells.

1975 ◽  
Vol 33 ◽  
pp. 318-319
Author(s):  
Joe A. Mascorro ◽  
Robert D. Yates
Keyword(s):  
Chromaffin Cells ◽  
Sodium Phosphate ◽  
Ganglion Cells ◽  
Ultrastructural Level ◽  
Osmic Acid ◽  
Adrenal Chromaffin Cells ◽  
Potassium Iodate ◽  
Perfusion Fluid ◽  
New Zealand White Rabbits ◽  
Adrenal Chromaffin

Extra-adrenal chromaffin organs (abdominal paraganglia) constitute rich sources of catecholamines. It is believed that these bodies contain norepinephrine exclusively. However, the present workers recently observed epinephrine type granules in para- ganglion cells. This report investigates catecholamine containing granules in rabbit paraganglia at the ultrastructural level.New Zealand white rabbits (150-170 grams) were anesthetized with 50 mg/kg Nembutal (IP) and perfused with 3% glutaraldehyde buffered with 0.2M sodium phosphate, pH 7.3. The retroperitoneal tissue blocks were removed and placed in perfusion fluid for 4 hours. The abdominal paraganglia were dissected from the blocks, diced, washed in phosphate buffer and fixed in 1% osmic acid buffered with phosphate. In other animals, the glutaraldehyde perfused tissue blocks were immersed for 1 hour in 3% glutaraldehyde/2.5% potassium iodate buffered as before. The paraganglia were then diced, separated into two vials and washed in the buffer. A portion of this tissue received osmic acid fixation.

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