scholarly journals Redistribution of a rab3-like GTP-binding protein from secretory granules to the Golgi complex in pancreatic acinar cells during regulated exocytosis

1994 ◽  
Vol 124 (1) ◽  
pp. 43-53 ◽  
Author(s):  
BP Jena ◽  
FD Gumkowski ◽  
EM Konieczko ◽  
GF von Mollard ◽  
R Jahn ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Complex ◽  
Binding Protein ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Apical Plasma Membrane ◽  
Gtp Binding Protein ◽  
Regulated Exocytosis ◽  
Gtp Binding

Regulated secretion from pancreatic acinar cells occurs by exocytosis of zymogen granules (ZG) at the apical plasmalemma. ZGs originate from the TGN and undergo prolonged maturation and condensation. After exocytosis, the zymogen granule membrane (ZGM) is retrieved from the plasma membrane and ultimately reaches the TGN. In this study, we analyzed the fate of a low M(r) GTP-binding protein during induced exocytosis and membrane retrieval using immunoblots as well as light and electron microscopic immunocytochemistry. This 27-kD protein, identified by a monoclonal antibody that recognizes rab3A and B, may be a novel rab3 isoform. In resting acinar cells, the rab3-like protein was detected primarily on the cytoplasmic face of ZGs, with little labeling of the Golgi complex and no significant labeling of the apical plasmalemma or any other intracellular membranes. Stimulation of pancreatic lobules in vitro by carbamylcholine for 15 min, resulted in massive exocytosis that led to a near doubling of the area of the apical plasma membrane. However, no relocation of the rab3-like protein to the apical plasmalemma was seen. After 3 h of induced exocytosis, during which time approximately 90% of the ZGs is released, the rab3-like protein appeared to translocate to small vesicles and newly forming secretory granules in the TGN. No significant increase of the rab3-like protein was found in the cytosolic fraction at any time during stimulation. Since the protein is not detected on the apical plasmalemma after stimulation, we conclude that recycling may involve a membrane dissociation-association cycle that accompanies regulated exocytosis.

GTP analogues cause release of the alpha subunit of the GTP binding protein, GO, from the plasma membrane of NG108-15 cells

1988 ◽  
Vol 152 (1) ◽  
pp. 243-251 ◽  
Author(s):  
Hayley McArdle ◽  
Ian Mullaney ◽  
Anthony Magee ◽  
Cecilia Unson ◽  
Graeme Milligan
Keyword(s):  
Plasma Membrane ◽  
Binding Protein ◽  
Alpha Subunit ◽  
Gtp Binding Protein ◽  
Gtp Binding

A GTP-binding protein required for secretion rapidly associates with secretory vesicles and the plasma membrane in yeast

Cell ◽  
1988 ◽  
Vol 53 (5) ◽  
pp. 753-768 ◽  
Author(s):  
Bruno Goud ◽  
Antti Salminen ◽  
Nancy C. Walworth ◽  
Peter J. Novick
Keyword(s):  
Plasma Membrane ◽  
Binding Protein ◽  
Secretory Vesicles ◽  
Gtp Binding Protein ◽  
Gtp Binding

scholarly journals The small GTP-binding protein rab6 functions in intra-Golgi transport.

1994 ◽  
Vol 127 (6) ◽  
pp. 1575-1588 ◽  
Author(s):  
O Martinez ◽  
A Schmidt ◽  
J Salaméro ◽  
B Hoflack ◽  
M Roa ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Binding Protein ◽  
Retrograde Transport ◽  
Wild Type ◽  
Gtp Binding Protein ◽  
Anterograde Transport ◽  
Golgi Transport ◽  
Gtp Binding ◽  
Hemagglutinin Protein

Rab6 is a ubiquitous ras-like GTP-binding protein associated with the membranes of the Golgi complex (Goud, B., A. Zahraoui, A. Tavitian, and J. Saraste. 1990. Nature (Lond.). 345:553-556; Antony, C., C. Cibert, G. Géraud, A. Santa Maria, B. Maro, V. Mayau, and B. Goud. 1992. J. Cell Sci. 103: 785-796). We have transiently overexpressed in mouse L cells and human HeLa cells wild-type rab6, GTP (rab6 Q72L), and GDP (rab6 T27N) -bound mutants of rab6 and analyzed the intracellular transport of a soluble secreted form of alkaline phosphatase (SEAP) and of a plasma membrane protein, the hemagglutinin protein (HA) of influenza virus. Over-expression of wild-type rab6 and rab6 Q72L greatly reduced transport of both markers between cis/medial (alpha-mannosidase II positive) and late (sialyl-transferase positive) Golgi compartments, without affecting transport from the endoplasmic reticulum (ER) to cis/medial-Golgi or from the trans-Golgi network (TGN) to the plasma membrane. Whereas overexpression of rab6 T27N did not affect the individual steps of transport between ER and the plasma membrane, it caused an apparent delay in secretion, most likely due to the accumulation of the transport markers in late Golgi compartments. Overexpression of both rab6 Q72L and rab6 T27N altered the morphology of the Golgi apparatus as well as that of the TGN, as assessed at the immunofluorescence level with several markers. We interpret these results as indicating that rab6 controls intra-Golgi transport, either acting as an inhibitor in anterograde transport or as a positive regulator of retrograde transport.

scholarly journals The inhibitory GTP-binding protein (Gi) occurs in rat Leydig cells and is differentially modified by lutropin and 12-O-tetradecanoylphorbol 13-acetate

1988 ◽  
Vol 253 (3) ◽  
pp. 895-899 ◽  
Author(s):  
E A Platts ◽  
D Schulster ◽  
B A Cooke
Keyword(s):  
Plasma Membrane ◽  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Cholera Toxin ◽  
Pertussis Toxin ◽  
Leydig Cells ◽  
Binding Protein ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Subsequent Response

Luteinizing-hormone (LH)-stimulated cyclic AMP production in rat testis Leydig cells was desensitized by both LH and 12-O-tetradecanoylphorbol 13-acetate (TPA). However, TPA, but not LH, enhanced the subsequent response to cholera toxin. Treatment of the cells with pertussis toxin potentiated cyclic AMP production in both control and LH-desensitized cells, but did not potentiate further the responses obtained by TPA pretreatment. The results implicate the presence of an inhibitory GTP-binding protein (Gi), which may be inhibited by TPA. The presence of a Gi-like protein within the plasma membrane of Leydig cells was demonstrated by pertussis-toxin-catalysed [32P]ADP-ribosylation of a Mr-40000-41000 protein.

The ras-related small GTP-binding protein Rab4 is involved in regulated exocytosis of rat pancreatic acini

1998 ◽  
Vol 114 ◽  
pp. A488
Author(s):  
Hirohide Ohnishi ◽  
Tetsuya Mine ◽  
Tomohiro Tsuchida ◽  
Toshiro Fujita
Keyword(s):  
Binding Protein ◽  
Gtp Binding Protein ◽  
Pancreatic Acini ◽  
Regulated Exocytosis ◽  
Gtp Binding

Endocytosis at the apical plasma membrane of pancreatic acinar cells is regulated by tyrosine kinases

1999 ◽  
Vol 276 (2) ◽  
pp. C306-C311 ◽  
Author(s):  
Steven D. Freedman ◽  
Mark H. Katz ◽  
Eliza M. Parker ◽  
Andres Gelrud
Keyword(s):  
Plasma Membrane ◽  
Tyrosine Kinases ◽  
Src Kinase ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Apical Plasma Membrane ◽  
Specific Substrate ◽  
Pancreatic Acini ◽  
Kinase Activation ◽  
Acinar Lumen

We have shown that endocytosis at the apical plasma membrane of pancreatic acinar cells is regulated by the pH of the acinar lumen and is associated with cleavage of GP2, a glycosyl phosphatidylinositol-anchored protein. The aim of this study was to determine the transduction pathway by which endocytosis is activated. Apical endocytosis was studied in rat pancreatic acini by prestimulation with cholecystokinin followed by measurement of horseradish peroxidase (HRP) uptake. Lanthanum, staurosporine, and forskolin had no effect on HRP uptake. Cytochalasin D significantly inhibited endocytosis, indicating a dependence on actin filament integrity. Genistein and the specific tyrphostin inhibitor B42 also inhibited HRP uptake, implicating tyrosine kinases in the regulation of HRP uptake. With the use of an Src kinase-specific substrate, Src kinase activity was temporally related to activation of endocytosis. The tyrosine-dependent phosphorylation of an 85-kDa substrate in both rat and mouse pancreatic acini correlated with Src kinase activation and pH-dependent regulation of HRP uptake. These results indicate that apical endocytosis in acinar cells is associated with tyrosine kinase activation and is dependent on the actin cytoskeleton.

Non-steroidal anti-inflammatory drugs: Effects on a GTP binding protein within the neutrophil plasma membrane

1991 ◽  
Vol 41 (11) ◽  
pp. 1567-1573 ◽  
Author(s):  
Steven B. Abramson ◽  
Joanna Leszczynska-Piziak ◽  
Kathleen Haines ◽  
Joan Reibman
Keyword(s):  
Plasma Membrane ◽  
Binding Protein ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Inflammatory Drugs ◽  
Anti Inflammatory
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