Transport of proteins to the plant vacuole is not by bulk flow through the secretory system, and requires positive sorting information.

C. Dorel, T. A. Voelker, Eliot M Herman, M. J. Chrispeels

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Plant cells, like other eukaryotic cells, use the secretory pathway to target proteins to the vacuolar/lysosomal compartment and to the extracellular space. We wished to determine whether the presence of a hydrophobic signal peptide would result in the transport of a reporter protein to vacuoles by bulk flow; to investigate this question, we expressed a chimeric gene in transgenic tobacco. The chimeric gene, Phalb, used for this study consists of the 1,188-bp 5' upstream sequence and the hydrophobic signal sequence of a vacuolar seed protein phytohemagglutinin, and the coding sequence of a cytosolic seed albumin (PA2). The chimeric protein PHALB cross-reacted with antibodies to PA2 and was found in the seeds of the transgenic plants (approximately 0.7% of total protein), but not in the leaves, roots, or flowers. Immunoblot analyses of seed extracts revealed four glycosylated polypeptides ranging in molecular weight from 29,000 to 32,000. The four polypeptides are glycoforms of a single polypeptide of Mr 27,000, and the heterogeneity is due to the presence of high mannose and endoglycosidase H-resistant glycans. The PHALB products reacted with an antiserum specific for complex plant glycans indicating that the glycans had been modified in the Golgi apparatus. Subcellular fractionation of glycerol extracts of mature seeds showed that only small amounts of PHALB accumulated in the protein storage vacuoles of the tobacco seeds. In homogenates made in an isotonic medium, very little PHALB was associated with the organelle fraction containing the endoplasmic reticulum and Golgi apparatus; most of it was in the soluble fraction. We conclude that PHALB passed through the Golgi apparatus, but did not arrive in the vacuoles. Transport to vacuoles is not by a bulk-flow mechanism, once proteins have entered the secretory system, and requires information beyond that provided by a hydrophobic signal peptide.

Original languageEnglish (US)
Pages (from-to)327-337
Number of pages11
JournalJournal of Cell Biology
Volume108
Issue number2
StatePublished - Feb 1989
Externally publishedYes

Fingerprint

Vacuoles
Carrier Proteins
Seeds
Golgi Apparatus
Protein Sorting Signals
Proteins
Polysaccharides
Peptides
Tobacco
Glycoside Hydrolases
Secretory Pathway
Genetically Modified Plants
Plant Cells
Extracellular Space
Eukaryotic Cells
Phytohemagglutinins
Mannose
Information Systems
Endoplasmic Reticulum
Organelles

ASJC Scopus subject areas

  • Cell Biology

Cite this

Transport of proteins to the plant vacuole is not by bulk flow through the secretory system, and requires positive sorting information. / Dorel, C.; Voelker, T. A.; Herman, Eliot M; Chrispeels, M. J.

In: Journal of Cell Biology, Vol. 108, No. 2, 02.1989, p. 327-337.

Research output: Contribution to journalArticle

@article{d933eb6e7b534608ae395d4568d17ceb,
title = "Transport of proteins to the plant vacuole is not by bulk flow through the secretory system, and requires positive sorting information.",
abstract = "Plant cells, like other eukaryotic cells, use the secretory pathway to target proteins to the vacuolar/lysosomal compartment and to the extracellular space. We wished to determine whether the presence of a hydrophobic signal peptide would result in the transport of a reporter protein to vacuoles by bulk flow; to investigate this question, we expressed a chimeric gene in transgenic tobacco. The chimeric gene, Phalb, used for this study consists of the 1,188-bp 5' upstream sequence and the hydrophobic signal sequence of a vacuolar seed protein phytohemagglutinin, and the coding sequence of a cytosolic seed albumin (PA2). The chimeric protein PHALB cross-reacted with antibodies to PA2 and was found in the seeds of the transgenic plants (approximately 0.7{\%} of total protein), but not in the leaves, roots, or flowers. Immunoblot analyses of seed extracts revealed four glycosylated polypeptides ranging in molecular weight from 29,000 to 32,000. The four polypeptides are glycoforms of a single polypeptide of Mr 27,000, and the heterogeneity is due to the presence of high mannose and endoglycosidase H-resistant glycans. The PHALB products reacted with an antiserum specific for complex plant glycans indicating that the glycans had been modified in the Golgi apparatus. Subcellular fractionation of glycerol extracts of mature seeds showed that only small amounts of PHALB accumulated in the protein storage vacuoles of the tobacco seeds. In homogenates made in an isotonic medium, very little PHALB was associated with the organelle fraction containing the endoplasmic reticulum and Golgi apparatus; most of it was in the soluble fraction. We conclude that PHALB passed through the Golgi apparatus, but did not arrive in the vacuoles. Transport to vacuoles is not by a bulk-flow mechanism, once proteins have entered the secretory system, and requires information beyond that provided by a hydrophobic signal peptide.",
author = "C. Dorel and Voelker, {T. A.} and Herman, {Eliot M} and Chrispeels, {M. J.}",
year = "1989",
month = "2",
language = "English (US)",
volume = "108",
pages = "327--337",
journal = "Journal of Cell Biology",
issn = "0021-9525",
publisher = "Rockefeller University Press",
number = "2",

}

TY - JOUR

T1 - Transport of proteins to the plant vacuole is not by bulk flow through the secretory system, and requires positive sorting information.

AU - Dorel, C.

AU - Voelker, T. A.

AU - Herman, Eliot M

AU - Chrispeels, M. J.

PY - 1989/2

Y1 - 1989/2

N2 - Plant cells, like other eukaryotic cells, use the secretory pathway to target proteins to the vacuolar/lysosomal compartment and to the extracellular space. We wished to determine whether the presence of a hydrophobic signal peptide would result in the transport of a reporter protein to vacuoles by bulk flow; to investigate this question, we expressed a chimeric gene in transgenic tobacco. The chimeric gene, Phalb, used for this study consists of the 1,188-bp 5' upstream sequence and the hydrophobic signal sequence of a vacuolar seed protein phytohemagglutinin, and the coding sequence of a cytosolic seed albumin (PA2). The chimeric protein PHALB cross-reacted with antibodies to PA2 and was found in the seeds of the transgenic plants (approximately 0.7% of total protein), but not in the leaves, roots, or flowers. Immunoblot analyses of seed extracts revealed four glycosylated polypeptides ranging in molecular weight from 29,000 to 32,000. The four polypeptides are glycoforms of a single polypeptide of Mr 27,000, and the heterogeneity is due to the presence of high mannose and endoglycosidase H-resistant glycans. The PHALB products reacted with an antiserum specific for complex plant glycans indicating that the glycans had been modified in the Golgi apparatus. Subcellular fractionation of glycerol extracts of mature seeds showed that only small amounts of PHALB accumulated in the protein storage vacuoles of the tobacco seeds. In homogenates made in an isotonic medium, very little PHALB was associated with the organelle fraction containing the endoplasmic reticulum and Golgi apparatus; most of it was in the soluble fraction. We conclude that PHALB passed through the Golgi apparatus, but did not arrive in the vacuoles. Transport to vacuoles is not by a bulk-flow mechanism, once proteins have entered the secretory system, and requires information beyond that provided by a hydrophobic signal peptide.

AB - Plant cells, like other eukaryotic cells, use the secretory pathway to target proteins to the vacuolar/lysosomal compartment and to the extracellular space. We wished to determine whether the presence of a hydrophobic signal peptide would result in the transport of a reporter protein to vacuoles by bulk flow; to investigate this question, we expressed a chimeric gene in transgenic tobacco. The chimeric gene, Phalb, used for this study consists of the 1,188-bp 5' upstream sequence and the hydrophobic signal sequence of a vacuolar seed protein phytohemagglutinin, and the coding sequence of a cytosolic seed albumin (PA2). The chimeric protein PHALB cross-reacted with antibodies to PA2 and was found in the seeds of the transgenic plants (approximately 0.7% of total protein), but not in the leaves, roots, or flowers. Immunoblot analyses of seed extracts revealed four glycosylated polypeptides ranging in molecular weight from 29,000 to 32,000. The four polypeptides are glycoforms of a single polypeptide of Mr 27,000, and the heterogeneity is due to the presence of high mannose and endoglycosidase H-resistant glycans. The PHALB products reacted with an antiserum specific for complex plant glycans indicating that the glycans had been modified in the Golgi apparatus. Subcellular fractionation of glycerol extracts of mature seeds showed that only small amounts of PHALB accumulated in the protein storage vacuoles of the tobacco seeds. In homogenates made in an isotonic medium, very little PHALB was associated with the organelle fraction containing the endoplasmic reticulum and Golgi apparatus; most of it was in the soluble fraction. We conclude that PHALB passed through the Golgi apparatus, but did not arrive in the vacuoles. Transport to vacuoles is not by a bulk-flow mechanism, once proteins have entered the secretory system, and requires information beyond that provided by a hydrophobic signal peptide.

UR - http://www.scopus.com/inward/record.url?scp=0024613977&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024613977&partnerID=8YFLogxK

M3 - Article

C2 - 2645295

AN - SCOPUS:0024613977

VL - 108

SP - 327

EP - 337

JO - Journal of Cell Biology

JF - Journal of Cell Biology

SN - 0021-9525

IS - 2

ER -