scholarly journals Identification and characterization of a mouse cell mutant defective in the intracellular transport of glycoproteins.

1987 ◽  
Vol 105 (2) ◽  
pp. 647-657 ◽  
Author(s):  
F Tufaro ◽  
M D Snider ◽  
S L McKnight

We have isolated a mutant line of mouse L cells, termed gro29, in which the growth of herpes simplex virus (HSV) and vesicular stomatitis virus (VSV) is defective. The block occurs late in the infectious cycle of both viruses. We demonstrate that HSV and VSV enter gro29 cells normally, negotiate the early stages of infection, yet are impaired at a late stage of virus maturation. During VSV infection of the mutant cell line, intracellular transport of its glycoprotein (G protein) is slowed. Pulse-chase experiments showed that oligosaccharide processing is impeded, and immunofluorescence localization revealed an accumulation of G protein in a juxtanuclear region that contains the Golgi complex. We conclude that export of newly made glycoproteins is defective in gro29 cells, and speculate that this defect may reflect a lesion in the glycoprotein transport 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.


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.


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.


1981 ◽  
Vol 90 (3) ◽  
pp. 697-704 ◽  
Author(s):  
E Fries ◽  
J E Rothman

Previous reports demonstrated that the vesicular stomatitis viral glycoprotein (G protein), initially present in membranes of a Chinese hamster ovary mutant cell line (clone 15B) that is incapable of terminal glycosylation, can be transferred in vitro to exogenous Golgi membranes and there glycosylated (E. Fries and J. E. Rothman, 1980, Proc. Natl. Acad. Sci. U. S. A. 77:3870-3874; and J. E. Rothman and E. Fries, 1981, J. Cell Biol. 89:162-168). Here we present evidence that Golgi-like membranes serve as donors of G protein in this process. Pulse-chase experiments revealed that the donor activity of membranes is greatest at approximately 10 min of chase, a time when G protein has been shown to have arrived in Golgi stacks (J. E. Bergmann, K. T. Tokuyasu, and S. J. Singer, 1981, Proc. Natl. Acad. Sci. U. S. A. 78:1746-1750). Additional evidence that the G protein that is transferred to exogenous Golgi membranes in vitro had already entered the Golgi membranes in vivo was provided by observations that its oligosaccharides had already been trimmed, and that its distribution in a sucrose density gradient was coincident with that of enzymatic markers of Golgi membranes. The capacity of this Golgi-like membrane to serve as donor is transient, declining within 5 min after "trimming" in vivo as the G protein enters a "nontransferable" pool. The rapidity of the process suggests that both the "transferable" and "nontransferable" pools of G protein reside in Golgi-like membranes.


1983 ◽  
Vol 97 (5) ◽  
pp. 1381-1388 ◽  
Author(s):  
R Z Florkiewicz ◽  
A Smith ◽  
J E Bergmann ◽  
J K Rose

We have characterized two stable transformed mouse cell lines (CG1 and CTG1) that express either the normal vesicular stomatitis virus glycoprotein (G) or a truncated form of the G protein (TG) that lacks the COOH-terminal anchor sequences and is secreted from the cells. These cell lines were obtained using a hybrid vector consisting of the transforming DNA fragment of bovine papilloma virus linked to a segment of the SV40 expression vector pSV2 containing cloned cDNA encoding either the normal or truncated form of the vesicular stomatitis virus G protein. Using indirect immunofluorescence we have found that greater than 95% of the cells in each line express the G protein(s), although the level of expression within the population is variable. The normal G protein expressed in these cells obtains its complex oligosaccharides in less than 30 min and is transported to the cell surface. In contrast, the TG protein obtains its complex oligosaccharides with a half-time of about 2.5 h. Immunofluorescence data show an apparent concentration of the TG protein in the rough endoplasmic reticulum. These data together suggest that transfer of this anchorless protein from the rough endoplasmic reticulum to the Golgi apparatus is the rate-limiting step in its secretion. We observed, in addition to normal G protein, two smaller G-related proteins produced in the CG1 cell line. We suggest that these proteins could result from aberrant splicing from sites within the G mRNA sequence to the downstream acceptor in the pSV2 vector.


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.


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.


Sign in / Sign up

Export Citation Format

Share Document