Fucosylation of Membrane Proteins in Soybean Cultured Cells

Hori, Hidetaka; Kaushal, Gur P.; Elbein, Alan D.

doi:10.1104/pp.77.3.687

Cited by 12 publications

(6 citation statements)

References 30 publications

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“…The work reported here extends the conclusion reached in previous studies on animal (13,26), yeast (23), and viral (15) glycoproteins, that protein conformation is a major determinant in oligosaccharide modification. In those experiments the oligosaccharide side chains which remain unmodified in vivo are not accessible to endo H in vitro unless the proteins are first denatured.…”

Section: Discussionsupporting

confidence: 77%

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Oligosaccharide Side Chains of Glycoproteins that Remain in the High-Mannose Form Are Not Accessible to Glycosidases

Faye¹,

Johnson²,

Chrispeels³

1986

Plant Physiol.

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Glycoproteins present in the soluble and organelle fractions of developing bean (Phaseolus vulgaris) cotyledons were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, affinoblotting, fractionation on immobilized concanavalin A (ConA), and digestion of the oligosaccharide side chains with specific glycosidases before and after protein denaturation. These studies led to the following observations. (a) Bean cotyledons contain a large variety

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Section: Discussionsupporting

confidence: 77%

“…Many ofthe details ofthese processing steps have been worked out for animal cells (see Refs. 9 and 16) and preliminary investigations indicate that processing of glycoproteins in plant cells is similar in certain respects (5,6,12,13,21,24), but not others (e.g. plant glycoproteins lack sialic acid).…”

mentioning

confidence: 99%

Oligosaccharide Side Chains of Glycoproteins that Remain in the High-Mannose Form Are Not Accessible to Glycosidases

Faye¹,

Johnson²,

Chrispeels³

1986

Plant Physiol.

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“…Immunoprecipitates of phenylalanine ammonia-lyase subunits were prepared and analysed as described in the Experimental section. The relative intensities of the 77 000-Mr bands labelled with [3H]mannose are: control/tunicamycin, 16 the effect of tunicamycin on the induction of extractable enzyme activity. This was found to vary within and between experiments.…”

Section: Resultsmentioning

confidence: 99%

“…Tunicamycin is a nucleoside antibiotic that inhibits the dolichol phosphate-mediated N-linked glycosylation of proteins [13]. It has been widely used to study the effects of glycosylation on protein structure and functions, and there are several reports concerning its use in plant glycoprotein studies [14][15][16]. There are two reports which suggest that a plant phenylalanine ammonialyase [from maize (Zea mays)] may be covalently glycosylated [17,18], and it has been debated whether the removal of an 0linked glycosyl chain from a serine residue may be the mechanism for the post-translational production of the active-site dehydroalanine [6,18].…”

Section: Introductionmentioning

confidence: 99%

Wound-induced phenylalanine ammonia-lyase in potato (Solanum tuberosum) tuber discs. Significance of glycosylation and immunolocalization of enzyme subunits

Shaw

Bolwell²,

Smith

1990

Biochemical Journal

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1. Excised discs of potato (Solanum tuberosum) tuber were incubated with [3H]fucose and extracts were prepared and incubated with an antibody to phenylalanine ammonia-lyase. Analysis of the resulting immunoprecipitated proteins by SDS/PAGE showed [3H]mannose- and [3H]fucose-labelled bands with Mr values corresponding to those of phenylalanine ammonia-lyase subunits. 2. When potato discs were incubated with [3H]sugars in the presence of tunicamycin, an inhibitor of N-linked protein glycosylation, incorporation of radioactivity from [3H]mannose into the immunoprecipitated enzyme subunits was virtually eliminated, whereas that from [3H]fucose was only marginally inhibited. 3. Tunicamycin reduced the level of extractable phenylalanine ammonia-lyase activity induced in excised potato tuber discs. Kinetic analysis revealed that the Vmax value of the enzyme in crude extracts from tunicamycin-treated tissue was reduced, whereas the apparent Km values were unaffected. 4. Immunoprecipitation of the enzyme labelled in vivo with [35S]methionine showed that tunicamycin did not inhibit the synthesis of the enzyme protein per se, nor did it increase the degradation of the enzyme protein. 5. Immunoprecipitation of the enzyme labelled in vitro with [14C]nitromethane showed that tunicamycin did not affect the introduction of the dehydroalanine residue into the active site. 6. These results are consistent with the following hypothesis: tunicamycin inhibits the N-linked glycosylation of phenylalanine ammonia-lyase which, in turn, results in imperfect folding of the enzyme protein. The orientation of the active site is changed in such a way that the affinity of the enzyme for its substrate is unaffected, whereas the catalytic activity of the enzyme is reduced. 7. Both optical- and electron-microscopic immunolocalization studies with antibody to phenylalanine ammonia-lyase showed increased deposition of silver granules in cells in sections of potato discs in which induction of the enzyme was allowed to occur compared with cells from newly wounded tissue. The enzyme was located in the cytoplasm, and was possibly membrane-associated.

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“…In mammalian cells, swainsonine inhibits mannosidase II, the enzyme which removes a-1,3-and a-1,6-linked mannoses thus converting GlcNAcMan5GlcNAc2 to GlcNAcMan3GlcNAc2 (28). It has been shown that swainsonine most probably has the same effect on the processed OS ofPHA and that, as in mammalian cells (20), the inhibitor does not prevent fucosylation in plant cells (10,15). Therefore, in bean cotyledonary cells two different mannosidases are acting on glycoproteins, apparently with the same specificities of mammalian mannosidase I and II.…”

mentioning

confidence: 96%

Mannose Analog 1-Deoxymannojirimycin Inhibits the Golgi-Mediated Processing of Bean Storage Glycoproteins

Vitale

Zoppé²,

Bollini³

1989

Plant Physiol.

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The asparagine-linked oligosaccharide chains of glycoproteins can be processed to form a wide variety of structures. The Golgi complex is the main compartment involved in this processing. In mammalian cells the first enzyme acting along the Golgi processing pathway is mannosidase 1, whose action is a prerequisite for any further processing and which is inhibited by the mannose analog 1-deoxymannojirimycin (dMM). To have insights into the processing pathway in plant cells, we have studied the In vivo effect of dMM on the processing of the bean (Phaseolus vulgads) storage proteins phaseolin and phytohemagglutinin, two well characterized plant glycoproteins. Cotyledons obtained from developing seeds were labeled with radioactive leucine, glucosamine, or fucose in the presence or absence of dMM. Treatment with dMM fully inhibited the acquisition of resistance to endo-#-N-acetylglucosaminidase H by phaseolin and phytohemagglutinin and the incorporation of fucose into protein. Furthermore, the apparent molecular weight of the polypeptides of phaseolin and phytohemagglutinin synthesized in dMM-treated cotyledons was consistent with the exclusive presence of oligommanose oligosaccharide chains which had not been processed in the Golgi complex. The inhibition of processing did not prevent exit from the Golgi complex, and most probably the storage proteins were correcty targeted to the protein bodies as indicated by the posttranslatonal polypeptide cleavage of phaseolin. These resuits indicate that the action of a mannosidase is the first obligatory step of Golgi-mediated processing also in a plant cell and, together with data obtained in other laboratories on the In vitro specificity of glycosidases and glycosyltransferases present in the Golgi complex of plant cells, support the hypothesis that the key early reactions in Golgi-mediated processing are similar if not identical in plants and mammals.

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Fucosylation of Membrane Proteins in Soybean Cultured Cells

Cited by 12 publications

References 30 publications

Oligosaccharide Side Chains of Glycoproteins that Remain in the High-Mannose Form Are Not Accessible to Glycosidases

Oligosaccharide Side Chains of Glycoproteins that Remain in the High-Mannose Form Are Not Accessible to Glycosidases

Wound-induced phenylalanine ammonia-lyase in potato (Solanum tuberosum) tuber discs. Significance of glycosylation and immunolocalization of enzyme subunits

Mannose Analog 1-Deoxymannojirimycin Inhibits the Golgi-Mediated Processing of Bean Storage Glycoproteins

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