Cytosolic PLA2 in Zymogen Granule Fusion and Amylase Release: Inhibition of GTP-induced Fusion by Arachidonyl Trifluoromethyl Ketone Points to cPLA2 in G-Protein-mediated Secretory Vesicle Fusion

2006 ◽  
Vol 141 (1) ◽  
pp. 77-84 ◽  
Author(s):  
A. A. Sattar ◽  
R. Haque
Keyword(s):  
G Protein ◽  
Secretory Vesicle ◽  
Vesicle Fusion ◽  
Zymogen Granule ◽  
Amylase Release ◽  
Cytosolic Pla2

scholarly journals Complexin-2 redistributes to the membrane of muscle cells in response to insulin and contributes to GLUT4 translocation

2021 ◽  
Author(s):  
Martin Alejandro Pavarotti ◽  
Victoria Tokarz ◽  
Scott Frendo-Cumbo ◽  
Philip Bilan ◽  
Zhi Liu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Insulin Signalling ◽  
Muscle Cells ◽  
Secretory Vesicle ◽  
Vesicle Fusion ◽  
Glut4 Translocation ◽  
Vesicle Membrane ◽  
Actin Fiber ◽  
Complexin 2 ◽  
Intracellular Compartments

Insulin stimulates glucose uptake in muscle cells by rapidly redistributing vesicles containing GLUT4 glucose transporters from intracellular compartments to the plasma membrane. GLUT4 vesicle fusion requires formation of SNARE complexes between vesicular VAMP and plasma membrane syntaxin4 and SNAP23. SNARE accessory proteins usually regulate vesicle fusion processes. Complexins aide in neuro-secretory vesicle-membrane fusion by stabilizing trans-SNARE complexes but their participation in GLUT4 vesicle fusion is unknown. We report that complexin-2 is expressed and homogeneously distributed in L6 rat skeletal muscle cells. Upon insulin stimulation, a cohort of complexin-2 redistributes to the plasma membrane. Complexin-2 knockdown markedly inhibited GLUT4 translocation without affecting proximal insulin signalling of Akt/PKB phosphorylation and actin fiber remodelling. Similarly, complexin-2 overexpression decreased maximal GLUT4 translocation suggesting that the concentration of complexin-2 is finely tuned to vesicle fusion.  These findings reveal an insulin-dependent regulation of GLUT4 insertion into the plasma membrane involving complexin-2.

scholarly journals Presynaptic G-Protein-Coupled Receptors Dynamically Modify Vesicle Fusion, Synaptic Cleft Glutamate Concentrations, and Motor Behavior

2009 ◽  
Vol 29 (33) ◽  
pp. 10221-10233 ◽  
Author(s):  
T. Gerachshenko ◽  
E. Schwartz ◽  
A. Bleckert ◽  
H. Photowala ◽  
A. Seymour ◽  
...  
Keyword(s):  
G Protein ◽  
Motor Behavior ◽  
Synaptic Cleft ◽  
Vesicle Fusion ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals SNAP-25 gene family members differentially support secretory vesicle fusion

2017 ◽  
Vol 130 (11) ◽  
pp. 1877-1889 ◽  
Author(s):  
Swati Arora ◽  
Ingrid Saarloos ◽  
Robbelien Kooistra ◽  
Rhea van de Bospoort ◽  
Matthijs Verhage ◽  
...  
Keyword(s):  
Gene Family ◽  
Family Members ◽  
Secretory Vesicle ◽  
Vesicle Fusion

scholarly journals G protein beta -subunits activated by serotonin mediate presynaptic inhibition by regulating vesicle fusion properties

2006 ◽  
Vol 103 (11) ◽  
pp. 4281-4286 ◽  
Author(s):  
H. Photowala ◽  
T. Blackmer ◽  
E. Schwartz ◽  
H. E. Hamm ◽  
S. Alford
Keyword(s):  
G Protein ◽  
Presynaptic Inhibition ◽  
Vesicle Fusion ◽  
Beta Subunits

Digestive end products mobilize secretory proteins from subcellular stores in the pancreas

1981 ◽  
Vol 241 (1) ◽  
pp. G67-G73
Author(s):  
J. H. Grendell ◽  
S. S. Rothman
Keyword(s):  
Pancreatic Tissue ◽  
Pancreatic Acinar Cell ◽  
Supernatant Fraction ◽  
Tissue Homogenate ◽  
Secretory Proteins ◽  
Zymogen Granule ◽  
Zymogen Granules ◽  
Amylase Release ◽  
End Products ◽  
Effective Level

Two digestive end products, D-glucose and L-lysine, produced substantial concentration-dependent release of amylase and trypsinogen, respectively, from subcellular storage pools into a postmicrosomal supernatant fraction of rat pancreatic tissue homogenate. This process was selective in that D-glucose did not lead to trypsinogen release, while L-lysine did not effect amylase. An analogue of D-glucose, 2-deoxy-D-glucose, was much less potent than D-glucose on an equimolar basis. Half-maximal release for both end-product enzyme pairs occurred at concentrations within the range of normal plasma values for these end products in the rat. Although amylase release reached an apparent plateau when the concentration of glucose was increased beyond the maximally effective level, lysine concentrations higher than that maximally effective resulted in a fall in trypsinogen release that ultimately returned (at 3.0 mM L-lysine) to the level seen in its absence. When isolated zymogen granules were exposed to the same concentrations of D-glucose or L-lysine, a similar pattern of release was seen, indicating that the zymogen granules are a source of the enzymes released from the particulate phase of the homogenates. These findings can be explained most simply by the selective movement of digestive enzymes across zymogen granule membranes in response to the presence of appropriate end products. They are also consistent with the concept that digestive end products can act rapidly and directly on the pancreatic acinar cell to regulate the mixture of enzymes secreted in response to the specific hydrolytic needs of a meal.

scholarly journals Syncollin is required for efficient zymogen granule exocytosis

2005 ◽  
Vol 385 (3) ◽  
pp. 721-727 ◽  
Author(s):  
Barbara WÄSLE ◽  
Matthew TURVEY ◽  
Olga LARINA ◽  
Peter THORN ◽  
Jeremy SKEPPER ◽  
...  
Keyword(s):  
Physiological Role ◽  
Pancreatic Acinar Cell ◽  
Zymogen Granule ◽  
Zymogen Granules ◽  
Wild Type ◽  
Amylase Release ◽  
Two Photon ◽  
Compound Exocytosis ◽  
Granule Membrane

Syncollin is a 13 kDa protein that is present in the exocrine pancreas, where the majority of the protein is tightly attached to the luminal surface of the zymogen granule membrane. We have addressed the physiological role of syncollin by studying the phenotype of syncollin KO (knockout) mice. These mice show pancreatic hypertrophy and elevated pancreatic amylase levels. Further, secretagogue-stimulated amylase release from pancreatic lobules of syncollin KO mice was found to be reduced by about 45% compared with wild-type lobules, and the delivery of newly synthesized protein to zymogen granules was delayed, indicating that the mice have a pancreatic secretory defect. As determined by two-photon imaging, the number of secretagogue-stimulated exocytotic events in acini from syncollin KO mice was reduced by 50%. This reduction was accounted for predominantly by a loss of later, ‘secondary’ fusion events between zymogen granules and other granules that had already fused with the plasma membrane. We conclude that syncollin is required for efficient exocytosis in the pancreatic acinar cell, and that it plays a particularly important role in compound exocytosis.

scholarly journals Presynaptic G-Protein-Coupled Receptors Regulate Synaptic Cleft Glutamate via Transient Vesicle Fusion

2007 ◽  
Vol 27 (22) ◽  
pp. 5857-5868 ◽  
Author(s):  
E. J. Schwartz ◽  
T. Blackmer ◽  
T. Gerachshenko ◽  
S. Alford
Keyword(s):  
G Protein ◽  
Synaptic Cleft ◽  
Vesicle Fusion ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals Homotypic Secretory Vesicle Fusion Induced by the Protein Tyrosine Phosphatase MEG2 Depends on Polyphosphoinositides in T Cells

2003 ◽  
Vol 171 (12) ◽  
pp. 6661-6671 ◽  
Author(s):  
Huong Huynh ◽  
Xiaodong Wang ◽  
Weizhong Li ◽  
Nunzio Bottini ◽  
Scott Williams ◽  
...  
Keyword(s):  
T Cells ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Secretory Vesicle ◽  
Vesicle Fusion ◽  
Protein Tyrosine
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