Involvement of the Golgi Apparatus in the Synthesis and Secretion of Hydroxyproline-rich Cell Wall Glycoproteins
- 1 March 1975
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 55 (3), 536-541
- https://doi.org/10.1104/pp.55.3.536
Abstract
Pulse labeling of carrot root phloem parenchyma (Daucus carota L. cv. Nantes) tissue with 14C-proline followed by fractionation of the cytoplasmic organelles on sucrose gradients was used to determine the identity of the membranous organelles involved in the secretion of the hydroxyproline-rich glycoproteins of the cell wall. Identification of the organelles was done through electron-microscopical observations and through the localization of marker enzymes on the sucrose gradients. Enrichment of the organelles involved in secretion was determined by measuring the percentage of the incorporated radioactivity present as 14C-hydroxyproline. The Golgi apparatus (dictyosome) was found to be a major site of glycoprotein transport. This identification was based on the observed enrichment of dictyosomes paralleling the purification of newly synthesized cell-wall glycoproteins. A marker enzyme for the Golgi apparatus, inosinediphosphatase, banded with the newly synthesized cell wall glycoproteins on sequential isopycnic and rate zonal sucrose gradients. Marker enzymes for the endoplasmic reticulum and the plasma membrane were clearly separated from the dictyosome-rich fraction. UDP-arabinose arabinosyl transferase, an enzyme involved in the glycosylation of the peptide moiety of this glycoprotein, also banded with the dictyosomes on both kinds of gradients. The results suggest an important role of the Golgi apparatus in the biosynthesis and the secretion of the cell wall glycoproteins of higher plants.Keywords
This publication has 18 references indexed in Scilit:
- Isolation of an Enzyme System Which Will Catalyze the Glycosylation of ExtensinPlant Physiology, 1972
- Polysaccharide formation in plant Golgi bodiesBiochimica et Biophysica Acta (BBA) - General Subjects, 1971
- Synthesis and Transport of Hydroxyproline-rich Components in Suspension Cultures of Sycamore-Maple CellsPlant Physiology, 1970
- ISOLATION OF β-GLUCAN SYNTHETASE PARTICLES FROM PLANT CELLS AND IDENTIFICATION WITH GOLGI MEMBRANESProceedings of the National Academy of Sciences of the United States of America, 1969
- Synthesis and Secretion of Hydroxyproline Containing Macromolecules in Carrots. I. Kinetic AnalysisPlant Physiology, 1969
- Phosphatases and differentiation of the golgi apparatusJournal of Cell Science, 1969
- Isolation and partial characterization of hydroxyproline-rich glycopeptides obtained by enzymic degradation of primary cell wallsBiochemistry, 1969
- RADIOAUTOGRAPHIC COMPARISON OF THE UPTAKE OF GALACTOSE-H3 AND GLUCOSE-H3 IN THE GOLGI REGION OF VARIOUS CELLS SECRETING GLYCOPROTEINS OR MUCOPOLYSACCHARIDESThe Journal of cell biology, 1966
- Proteins and Plant Cell Walls. Proline to Hydroxyproline in Tobacco Suspension CulturesPlant Physiology, 1964
- A MICROCOLORIMETRIC METHOD FOR THE DETERMINATION OF INORGANIC PHOSPHORUSJournal of Biological Chemistry, 1953