scholarly journals Intracellular transport of the transmembrane glycoprotein G of vesicular stomatitis virus through the Golgi apparatus as visualized by electron microscope radioautography.

1982 ◽  
Vol 94 (1) ◽  
pp. 36-41 ◽  
Author(s):  
J J Bergeron ◽  
G J Kotwal ◽  
G Levine ◽  
P Bilan ◽  
R Rachubinski ◽  
...  

The intracellular migration of G protein in vesicular stomatitis virus-infected cells was visualized by light and electron microscope radioautography after a 2-min pulse with [3H]mannose followed by nonradioactive chase for various intervals. The radioactivity initially (at 5-10 min) appeared predominantly in the endoplasmic reticulum, and the [3H]mannose-labeled G protein produced was sensitive to endoglycosidase H. Silver grains were subsequently (at 30-40 min) observed over the Golgi apparatus, and the [3H]mannose-labeled G protein became resistant to endoglycosidase H digestion. Our data directly demonstrate the intracellular transport of a plasmalemma-destined transmembrane glycoprotein through the Golgi apparatus.

1989 ◽  
Vol 92 (4) ◽  
pp. 633-642
Author(s):  
J.K. Burkhardt ◽  
Y. Argon

The appearance of newly synthesized glycoprotein (G) of vesicular stomatitis virus at the surface of infected BHK cells is inhibited reversibly by treatment with carbonylcyanide m-chlorophenylhydrazone (CCCP). Under the conditions used, CCCP treatment depleted the cellular ATP levels by 40–60%, consistent with inhibition of transport at energy-requiring stages. The G protein that accumulates in cells treated with CCCP is heterogeneous. Most of it is larger than the newly synthesized G protein, is acylated with palmitic acid, and is resistant to endoglycosidase H (Endo H). Most of the arrested G protein is also sensitive to digestion with neuraminidase, indicating that it has undergone at least partial sialylation. A minority of G protein accumulates under these conditions in a less-mature form, suggesting its inability to reach the mid-Golgi compartment. The oligosaccharides of this G protein are Endo-H-sensitive and seem to be partly trimmed. Whereas sialylated G protein was arrested intracellularly, fucose-labelled G protein was able to complete its transport to the cell surface, indicating that a late CCCP-sensitive step separates sialylation from fucosylation. These post-translational modifications indicate that G protein can be transported as far as the trans-Golgi in the presence of CCCP and is not merely arrested in the endoplasmic reticulum.


1990 ◽  
Vol 110 (3) ◽  
pp. 625-635 ◽  
Author(s):  
J E Bergmann ◽  
P J Fusco

We have investigated the role of the smooth endoplasmic reticulum (SER) of UT-1 cells in the biogenesis of the glycoprotein (G) of vesicular stomatitis virus (VSV). Using immunofluorescence microscopy, we observed the wild type G protein in the SER of infected cells. When these cells were infected with the mutant VSV strain ts045, the G protein was unable to reach the Golgi apparatus at 40 degrees C, but was able to exit the rough endoplasmic reticulum (RER) and accumulate in the SER. Ribophorin II, a RER marker, remained excluded from the SER during the viral infection, ruling out the possibility that the infection had destroyed the separate identities of these two organelles. Thus, the mechanism that results in the retention of this mutant glycoprotein in the ER at 39.9 degrees C does not limit its lateral mobility within the ER system. We have also localized GRP78/BiP to the SER of UT-1 cells indicating that other mutant proteins may also have access to this organelle. Upon incubation at 32 degrees C, the mutant G protein was able to leave the SER and move to the Golgi apparatus. To measure how rapidly this transfer occurs, we assayed the conversion of the G protein's N-linked oligosaccharides from endoglycosidase H-sensitive to endoglycosidase H-resistant forms. After a 5-min lag, transport of the G protein followed first order kinetics (t1/2 = 15 min). In contrast, no lag was seen in the transport of G protein that had accumulated in the RER of control UT-1 cells lacking extensive SER. In these cells, the transport of G protein also exhibited first order kinetics (t1/2 = 17 min). Possible implications of this lag are discussed.


1980 ◽  
Vol 86 (1) ◽  
pp. 162-171 ◽  
Author(s):  
J E Rothman ◽  
H Bursztyn-Pettegrew ◽  
R E Fine

The G protein of vesicular stomatitis virus is a transmembrane glycoprotein that is transported from its site of synthesis in the rough endoplasmic reticulum to the plasma membrane via the Golgi apparatus. Pulse-chase experiments suggest that G is transported to the cell surface in two successive waves of clathrin-coated vesicles. The oligosaccharides of G protein carried in the early wave are of the "high-mannose" (G1) form, whereas the oligosaccharides in the second, later wave are of the mature "complex" (G2) form. the early wave is therefore proposed to correspond to transport of G in coated vesicles from the endoplasmic reticulum to the Golgi apparatus, and the succeeding wave to transport from the Golgi apparatus to the plasma membrane. The G1- and G2-containing coated vesicles appear to be structurally distinct, as judged by their differential precipitation by anticoated vesicle serum.


1979 ◽  
Vol 80 (2) ◽  
pp. 416-426 ◽  
Author(s):  
F N Katz ◽  
H F Lodish

Previous work has shown that the mRNA encoding the vesicular stomatitis virus (VSV) glycoprotein (G) is bound to the rough endoplasmic reticulum (RER) and that newly made G protein is localized to the RER. In this paper, we have investigated the topology and processing of the newly synthesized G protein in microsomal vesicles. G was labeled with [35S]methionine ([35S]met), either by pulse-labeling infected cells or by allowing membrane-bound polysomes containing nascent G polipeptides to complete G synthesis in vitro. In either case, digestion of microsomal vesicles with any of several proteases removes approximately 5% (30 amino acids) from each G molecule. These proteases will digest the entire G protein if detergents are present during digestion. Using the method of Dintzis (1961, Proc. Natl. Acad. Sci. U. S. A. 47:247--261) to order tryptic peptides (8), we show that peptides lost from G protein by protease treatment of closed vesicles are derived from the carboxyterminus of the molecule. The newly made VSV G in microsomal membranes is glycosylated. If carbohydrate is removed by glycosidases, the resultant peptide migrates more rapidly on polyacrylamide gels than the unglycosylated, G0, form synthesized in cell-free systems in the absence of membranes. We infer that some proteolytic cleavage of the polypeptide backbone is associated with membrane insertion of G. Further, our findings demonstrate that, soon after synthesis, G is found in a transmembrane, asymmetric orientation in microsomal membranes, with its carboxyterminus exposed to the extracisternal, or cytoplasmic, face of the vesicles, and with most or all of its amino-terminal peptides and its carbohydrate sequestered within the bilayer and lumen of the microsomes.


1983 ◽  
Vol 97 (6) ◽  
pp. 1815-1822 ◽  
Author(s):  
G J Strous ◽  
R Willemsen ◽  
P van Kerkhof ◽  
J W Slot ◽  
H J Geuze ◽  
...  

Human hepatoma cells, infected by vesicular stomatitis virus, offer a good system to study simultaneously the intracellular localization of a well defined transmembrane glycoprotein (VSV-G), a secretory glycoprotein (transferrin), and a nonglycosylated secretory protein (albumin). We used monospecific antibodies in combination with 5- and 8-nm colloidal gold particles complexed with protein A to immunolabel these proteins simultaneously in thin frozen sections of hepatoma cells. VSV-G, transferrin, and albumin are present in the same rough endoplasmic reticulum cisternae, the same Golgi compartments, and the same secretory vesicles. In the presence of the ionophore monensin intracellular transport is blocked at the trans cisternae of the Golgi complex, and VSV-G, transferrin, and albumin accumulate in dilated cisternae, which are apparently derived from the trans-Golgi elements. Glycoproteins, synthesized and secreted in the presence of monensin, are less acidic than those in control cultures. This is probably caused by a less efficient contact between the soluble secretory proteins and the membrane-bound glycosyltransferases that are present in the most monensin-affected (trans) Golgi cisternae.


1985 ◽  
Vol 5 (11) ◽  
pp. 3074-3083 ◽  
Author(s):  
C E Machamer ◽  
R Z Florkiewicz ◽  
J K Rose

We investigated the role of glycosylation in intracellular transport and cell surface expression of the vesicular stomatitis virus glycoprotein (G) in cells expressing G protein from cloned cDNA. The individual contributions of the two asparagine-linked glycans of G protein to cell surface expression were assessed by site-directed mutagenesis of the coding sequence to eliminate one or the other or both of the glycosylation sites. One oligosaccharide at either position was sufficient for cell surface expression of G protein in transfected cells, and the rates of oligosaccharide processing were similar to the rate observed for wild-type protein. However, the nonglycosylated G protein synthesized when both glycosylation sites were eliminated did not reach the cell surface. This protein did appear to reach a Golgi-like region, as determined by indirect immunofluorescence microscopy, however, and was modified with palmitic acid. It was also apparently not subject to increased proteolytic breakdown.


1985 ◽  
Vol 101 (6) ◽  
pp. 2036-2046 ◽  
Author(s):  
C Featherstone ◽  
G Griffiths ◽  
G Warren

Newly synthesized G protein of vesicular stomatitis virus is not transported to the surface of cultured mammalian cells during mitosis (Warren et al., 1983, J. Cell Biol. 97:1623-1628). To determine where intracellular transport is inhibited, we have examined the post-translational modifications of G protein, which are indicators of specific compartments on the transport pathway. G protein in mitotic cells had only endo H-sensitive oligosaccharides containing seven or eight mannose residues, but no terminal glucose, and was not fatty acylated. These modifications were indicative of processing only by enzymes of the endoplasmic reticulum (ER). Quantitative immunocytochemistry was used as an independent method to confirm that transport of G protein out of the ER was inhibited. The density of G protein in the ER cisternae was 2.5 times greater than in infected G1 cells treated similarly. Incubation of infected mitotic cells with cycloheximide, which inhibits protein synthesis without affecting transport, did not result in a decrease in the density of G protein in the ER cisternae, demonstrating that G protein cannot be chased out of the ER. These results suggest that intracellular transport stops at or before the first vesicle-mediated step on the pathway.


1994 ◽  
Vol 5 (2) ◽  
pp. 99-104 ◽  
Author(s):  
M. J. Almela ◽  
A. Irurzun ◽  
L. Carrasco

The naturally occurring isoflavonoid orobol exhibits antiviral effects against some animal viruses. Addition of the compound after virus entry inhibits the appearance of late viral protein synthesis in Vesicular Stomatitis Virus, influenza, or vaccinia virus-infected cells, but has no effect on poliovirus protein synthesis. Concentrations of the compound above 10–50 Mg ml−1 are sufficient to decrease the synthesis of VSV proteins when added early during infection, but have no effect on viral translation if added later, indicating that orobol does not block VSV translation directly. The synthesis of VSV nucleic acids is one of the targets of this flavonoid. The synthesis of both minus and plus-stranded viral RNA are inhibited by orobol when added during the first 2 h of infection. In addition, this compound interferes potently with the glycosylation of VSV G protein, indicating that orobol has several targets of antiviral action. The possibility that orobol interferes with the function of the cellular vesicular system is discussed.


1984 ◽  
Vol 99 (1) ◽  
pp. 260-271 ◽  
Author(s):  
J E Rothman ◽  
R L Miller ◽  
L J Urbani

The transfer of the vesicular stomatitis virus-encoded glycoprotein (G protein) between Golgi populations in fused cells (Rothman, J. E., L. J. Urbani, and R. Brands. 1984. J. Cell Biol. 99:248-259) is exploited here to study and to help define the compartmental organization of the Golgi stack and to characterize the mechanism of intercompartmental transport. We find that G protein that has just received its peripheral N-acetylglucosamine in the Golgi complex of one cell is efficiently transferred to the Golgi complex of another cell to receive galactose (Gal). Remarkably, this transport occurs at the same rate between these two compartments whether they are present in the same or different Golgi populations. Therefore, a dissociative (presumably vesicular) transport step moves G protein from one part of the Golgi in which N-acetylglucosamine is added to another in which Gal is added. Minutes later, upon receiving Gal, the same G protein molecules are very poorly transferred to an exogenous Golgi population after cell fusion. Therefore, once this intercompartmental transfer has already taken place (before fusion), it cannot take place again (after fusion); i.e., transport across the compartment boundary in the Golgi complex that separates the sites of N-acetylglucosamine and Gal incorporation is a vectorial process. We conclude that transfers between Golgi cisternae occur by a stochastic process in which transport vesicles budding from cisternae dissociate, can diffuse away, and then attach to and fuse with the appropriate target cisterna residing in the same or in a different stack, based on a biochemical pairing after a random encounter. Under these circumstances, a transported protein would almost always randomize among stacks with each intercisternal transfer; it would not progress systematically through a single stack. Altogether, our studies define three sequential compartments in the Golgi stack.


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