scholarly journals Variants of vaccinia virus hemagglutinin altered in intracellular transport.

1986 ◽  
Vol 6 (11) ◽  
pp. 3734-3745 ◽  
Author(s):  
H Shida

Two classes of revertants were isolated from a vaccinia virus mutant whose hemagglutinins (HAs) accumulate on nuclear envelopes and rough endoplasmic reticulums. The HAs of one of the revertants had the same phenotype as the wild type, i.e., rapid and efficient movement to the cell surface. The HAs of the second class had biphasic transport: rapid export to the cell surface as in the wild type and slow movement to the medial cisternae of the Golgi apparatus. Biochemical and nucleotide sequence analyses showed that the HAs of all the mutants examined that have defects in transport from the rough endoplasmic reticulum to the Golgi apparatus have altered cytoplasmic domains and that the HAs of the second class of revertants lack the whole cytoplasmic domain, while the HAs of the first class of revertants have a wild-type cytoplasmic domain.

1986 ◽  
Vol 6 (11) ◽  
pp. 3734-3745
Author(s):  
H Shida

Two classes of revertants were isolated from a vaccinia virus mutant whose hemagglutinins (HAs) accumulate on nuclear envelopes and rough endoplasmic reticulums. The HAs of one of the revertants had the same phenotype as the wild type, i.e., rapid and efficient movement to the cell surface. The HAs of the second class had biphasic transport: rapid export to the cell surface as in the wild type and slow movement to the medial cisternae of the Golgi apparatus. Biochemical and nucleotide sequence analyses showed that the HAs of all the mutants examined that have defects in transport from the rough endoplasmic reticulum to the Golgi apparatus have altered cytoplasmic domains and that the HAs of the second class of revertants lack the whole cytoplasmic domain, while the HAs of the first class of revertants have a wild-type cytoplasmic domain.


1984 ◽  
Vol 99 (6) ◽  
pp. 2011-2023 ◽  
Author(s):  
J W Wills ◽  
R V Srinivas ◽  
E Hunter

The envelope glycoproteins of Rous sarcoma virus (RSV), gp85 and gp37, are anchored in the membrane by a 27-amino acid, hydrophobic domain that lies adjacent to a 22-amino acid, cytoplasmic domain at the carboxy terminus of gp37. We have altered these cytoplasmic and transmembrane domains by introducing deletion mutations into the molecularly cloned sequences of a proviral env gene. The effects of the mutations on the transport and subcellular localization of the Rous sarcoma virus glycoproteins were examined in monkey (CV-1) cells using an SV40 expression vector. We found, on the one hand, that replacement of the nonconserved region of the cytoplasmic domain with a longer, unrelated sequence of amino acids (mutant C1) did not alter the rate of transport to the Golgi apparatus nor the appearance of the glycoprotein on the cell surface. Larger deletions, extending into the conserved region of the cytoplasmic domain (mutant C2), resulted in a slower rate of transport to the Golgi apparatus, but did not prevent transport to the cell surface. On the other hand, removal of the entire cytoplasmic and transmembrane domains (mutant C3) did block transport and therefore did not result in secretion of the truncated protein. Our results demonstrate that the C3 polypeptide was not transported to the Golgi apparatus, although it apparently remained in a soluble, nonanchored form in the lumen of the rough endoplasmic reticulum; therefore, it appears that this mutant protein lacks a functional sorting signal. Surprisingly, subcellular localization by internal immunofluorescence revealed that the C3 protein (unlike the wild type) did not accumulate on the nuclear membrane but rather in vesicles distributed throughout the cytoplasm. This observation suggests that the wild-type glycoproteins (and perhaps other membrane-bound or secreted proteins) are specifically transported to the nuclear membrane after their biosynthesis elsewhere in the rough endoplasmic reticulum.


1985 ◽  
Vol 100 (3) ◽  
pp. 704-714 ◽  
Author(s):  
C Doyle ◽  
M G Roth ◽  
J Sambrook ◽  
M J Gething

Mutations have been introduced into the cloned DNA sequences coding for influenza virus hemagglutinin (HA), and the resulting mutant genes have been expressed in simian cells by the use of SV40-HA recombinant viral vectors. In this study we analyzed the effect of specific alterations in the cytoplasmic domain of the HA molecule on its rate of biosynthesis and transport, cellular localization, and biological activity. Several of the mutants displayed abnormalities in the pathway of transport from the endoplasmic reticulum to the cell surface. One mutant HA remained within the endoplasmic reticulum; others were delayed in reaching the Golgi apparatus after core glycosylation had been completed in the endoplasmic reticulum, but then progressed at a normal rate from the Golgi apparatus to the cell surface; another was delayed in transport from the Golgi apparatus to the plasma membrane. However, two mutants were indistinguishable from wild-type HA in their rate of movement from the endoplasmic reticulum through the Golgi apparatus to the cell surface. We conclude that changes in the cytoplasmic domain can powerfully influence the rate of intracellular transport and the efficiency with which HA reaches the cell surface. Nevertheless, absolute conservation of this region of the molecule is not required for maturation and efficient expression of a biologically active HA on the surface of infected cells.


2000 ◽  
Vol 74 (7) ◽  
pp. 3353-3365 ◽  
Author(s):  
Chi-Long Lin ◽  
Che-Sheng Chung ◽  
Hans G. Heine ◽  
Wen Chang

ABSTRACT An immunodominant antigen, p35, is expressed on the envelope of intracellular mature virions (IMV) of vaccinia virus. p35 is encoded by the viral late gene H3L, but its role in the virus life cycle is not known. This report demonstrates that soluble H3L protein binds to heparan sulfate on the cell surface and competes with the binding of vaccinia virus, indicating a role for H3L protein in IMV adsorption to mammalian cells. A mutant virus defective in expression of H3L (H3L−) was constructed; the mutant virus has a small plaque phenotype and 10-fold lower IMV and extracellular enveloped virion titers than the wild-type virus. Virion morphogenesis is severely blocked and intermediate viral structures such as viral factories and crescents accumulate in cells infected with the H3L− mutant virus. IMV from the H3L− mutant virus are somewhat altered and less infectious than wild-type virions. However, cells infected by the mutant virus form multinucleated syncytia after low pH treatment, suggesting that H3L protein is not required for cell fusion. Mice inoculated intranasally with wild-type virus show high mortality and severe weight loss, whereas mice infected with H3L− mutant virus survive and recover faster, indicating that inactivation of the H3L gene attenuates virus virulence in vivo. In summary, these data indicate that H3L protein mediates vaccinia virus adsorption to cell surface heparan sulfate and is important for vaccinia virus infection in vitro and in vivo. In addition, H3L protein plays a role in virion assembly.


1984 ◽  
Vol 68 (1) ◽  
pp. 83-94
Author(s):  
C.J. Flickinger

The production, transport, and disposition of material labelled with [3H]mannose were studied in microsurgically enucleated and control amoebae. Cells were injected with the precursor and samples were prepared for electron-microscope radioautography at intervals, up to 24 h later. Control cells showed heavy labelling of the rough endoplasmic reticulum and the Golgi apparatus at early intervals after injection. Later, labelling of groups of small vesicles increased, and the percentage of grains over the cell surface peaked 12 h after administration of the precursor. Two major changes were detected in enucleate amoebae. First, the kinetics of labelling of cell organelles with [3H]mannose were altered in the absence of the nucleus. The Golgi apparatus and cell surface both displayed maximal labelling at later intervals in enucleates, and the percentage of grains over the rough endoplasmic reticulum varied less with time in enucleated than in control cells. Second, the distribution of radioactivity was altered. A greater percentage of grains was associated with lysosomes in enucleates than in control cells. The change in the kinetics of labelling of the endoplasmic reticulum, Golgi apparatus and cell surface indicates that intracellular transport of surface material was slower in the absence of the nucleus. It is suggested that this is related to the decreased motility of enucleate cells.


2009 ◽  
Vol 8 (9) ◽  
pp. 1407-1417 ◽  
Author(s):  
Maria Lucia Sampaio Güther ◽  
Kenneth Beattie ◽  
Douglas J. Lamont ◽  
John James ◽  
Alan R. Prescott ◽  
...  

ABSTRACT A Trypanosoma brucei TbGPI12 null mutant that is unable to express cell surface procyclins and free glycosylphosphatidylinositols (GPI) revealed that these are not the only surface coat molecules of the procyclic life cycle stage. Here, we show that non-GPI-anchored procyclins are N-glycosylated, accumulate in the lysosome, and appear as proteolytic fragments in the medium. We also show, using lectin agglutination and galactose oxidase-NaB3H4 labeling, that the cell surface of the TbGPI12 null parasites contains glycoconjugates that terminate in sialic acid linked to galactose. Following desialylation, a high-apparent-molecular-weight glycoconjugate fraction was purified by ricin affinity chromatography and gel filtration and shown to contain mannose, galactose, N-acetylglucosamine, and fucose. The latter has not been previously reported in T. brucei glycoproteins. A proteomic analysis of this fraction revealed a mixture of polytopic transmembrane proteins, including P-type ATPase and vacuolar proton-translocating pyrophosphatase. Immunolocalization studies showed that both could be labeled on the surfaces of wild-type and TbGPI12 null cells. Neither galactose oxidase-NaB3H4 labeling of the non-GPI-anchored surface glycoconjugates nor immunogold labeling of the P-type ATPase was affected by the presence of procyclins in the wild-type cells, suggesting that the procyclins do not, by themselves, form a macromolecular barrier.


1988 ◽  
Vol 107 (5) ◽  
pp. 1655-1667 ◽  
Author(s):  
E Friederich ◽  
H J Fritz ◽  
W B Huttner

The effect of tyrosine sulfation on the transport of a constitutively secreted protein, yolk protein 2 (YP2) of Drosophila melanogaster, to the cell surface was investigated after expression of YP2 in mouse fibroblasts. Inhibition of YP2 sulfation was achieved by two distinct approaches. First, the single site of sulfation in YP2, tyrosine 172, was changed to phenylalanine by oligonucleotide-directed mutagenesis. Second, L cell clones stably expressing YP2 were treated with chlorate, a reversible inhibitor of sulfation. Pulse-chase experiments with transfected L cell clones showed that the half-time of transport from the rough endoplasmic reticulum to the cell surface of the unsulfated mutant YP2 and the unsulfated wild-type YP2 produced in the presence of chlorate was 15-18 min slower than that of the sulfated wild-type YP2. Control experiments indicated (a) that the tyrosine to phenylalanine change itself did not affect YP2 transport, (b) that the retardation of YP2 transport by chlorate occurred only with sulfatable but not with unsulfatable YP2, (c) that the transport difference between wild-type and mutant YP2 was not due to the level of YP2 expression, and (d) that transport of the endogenous secretory protein fibronectin was the same in L cell clones expressing wild-type and mutant YP2. Since the half-time of transport of wild-type YP2 from the intracellular site of sulfation, the trans-Golgi, to the cell surface was found to be 10 min, the 15-18-min retardation seen upon inhibition of tyrosine sulfation reflected a two- to threefold increase in the half-time of trans-Golgi to cell surface transport, which was most probably caused by an increased residence time of unsulfated YP2 in the trans-Golgi. The results demonstrate a role of tyrosine sulfation in the intracellular transport of a constitutively secreted protein.


1992 ◽  
Vol 175 (1) ◽  
pp. 257-266 ◽  
Author(s):  
J Lesley ◽  
Q He ◽  
K Miyake ◽  
A Hamann ◽  
R Hyman ◽  
...  

The CD44-negative T lymphoma AKR1 (CD44.2 genotype) was transfected with a CD44.1 cDNA. The intact cDNA conferred on the transfected cells the ability to bind hyaluronic acid (HA) both from solution and immobilized on culture plates. It also conferred a CD44-dependent and hyaluronidase-sensitive increase in adhesion to a lymph node endothelial cell line. A mutant cDNA which codes for a CD44 molecule lacking most of the cytoplasmic domain of CD44 was also transfected into AKR1, and cell sorting was used to select transfectants expressing levels of cell surface CD44 expression comparable with the line transfected with the wild-type CD44 cDNA. The cells transfected with the mutant construct bound fluoresceinated HA from solution very poorly, but did adhere to immobilized HA, though less well than cells transfected with the wild-type construct. This result indicates that the cytoplasmic domain of CD44 is necessary for binding of HA from solution but is not required for binding to immobilized HA, although it may contribute to adhesion following ligand recognition. A monoclonal antibody (mAb), IRAWB 14, which reacts with CD44 on all CD44+ cells dramatically induced HA binding by some CD44+ cell lines that did not constitutively bind HA. The transfectant expressing a CD44 molecule with a truncated cytoplasmic domain could be induced by this antibody to bind fluoresceinated-HA from solution. Splenic T cells did not bind fluoresceinated HA constitutively. In the presence of the IRAWB 14 mAb, virtually all CD44+ splenic T cells bound HA. Induction was immediate and occurred equally well at room temperature and at 4 degrees C, indicating that the new HA-binding activity was due to preexistent CD44 molecules. These results are compatible with an antibody-induced activation of CD44 by either a conformational change in the CD44 molecule or a change in the distribution of CD44 molecules on the cell surface.


1998 ◽  
Vol 111 (2) ◽  
pp. 249-260 ◽  
Author(s):  
J.O. Gonatas ◽  
Y.J. Chen ◽  
A. Stieber ◽  
Z. Mourelatos ◽  
N.K. Gonatas

MG160, a type I cysteine-rich membrane sialoglycoprotein residing in the medial cisternae of the rat Golgi apparatus, is highly homologous to CFR, a fibroblast growth factor receptor, and ESL-1, an E-selectin ligand located at the cell surface of mouse myeloid cells and recently detected in the Golgi apparatus as well. The mechanism for the transport of MG160 from the Golgi apparatus to the cell surface is unknown. In this study we found that differential processing of the carboxy-terminal cytoplasmic domain (CD), consisting of amino acids Arg1159 Ile Thr Lys Arg Val Thr Arg Glu Leu Lys Asp Arg1171, resulted in the partial transport of the protein to the plasma membrane and filopodia. In Chinese hamster ovary cells (CHO), stably transfected with the entire cDNA encoding MG160, the protein was localized in the Golgi apparatus. However, when the terminal Arg1171 or up to nine distal amino acids were deleted, the protein was distributed to the plasma membrane and filopodia as well as the Golgi apparatus. This report shows that the CD of an endogenous type I Golgi protein is important for its efficient retention and identifies a unique residue preference in this process. Cleavage within the CD of MG160 may constitute a regulatory mechanism for the partial export of the protein from the Golgi apparatus to the plasma membrane and filopodia.


1998 ◽  
Vol 111 (4) ◽  
pp. 511-519 ◽  
Author(s):  
K. Matter ◽  
M.S. Balda

Tight junctions form a morphological and physical border between the apical and the basolateral cell surface domains of epithelial cells; hence assembly of tight junctions could occur from both of the two plasma membrane domains. We show here that the C-terminal cytoplasmic domain of occludin, the only known transmembrane protein of tight junctions, was sufficient to mediate basolateral expression of a chimeric protein. Since this chimera was transported directly to the basolateral membrane during biosynthesis, the C-terminal domain of occludin contains a basolateral targeting signal. Additionally, the C-terminal domain of occludin was also able to mediate endocytosis. Thus, the C-terminal cytoplasmic domain appears to govern intracellular transport of occludin. To test whether the basolateral membrane is an obligatory intermediate in transport of occludin to tight junctions, we analyzed the expression of occludin molecules rendered unable to efficiently integrate into tight junctions by the introduction of N-linked glycosylation sites into the two extracellular loops. Indeed, glycosylated occludin accumulated in the basolateral membrane, supporting a model in which the biogenesis of tight junctions occurs from this cell-surface domain.


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