Transport of phosphocholine in higher plant cells: 31P nuclear magnetic resonance studies

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 87; no. 11; pp. 4280 - 4283
• Main Authors: Gout, E. (Universite Joseph Fourier, Grenoble, France), Bligny, R, Roby, C, Douce, R
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.06.1990; National Acad Sciences
• Subjects: ACER PSEUDOPLATANUS; BIOLOGIA; Biological and medical sciences; BIOLOGIE; BIOLOGY; Cell physiology; Cell walls; CHOLINE; COLINA; Cultured cells; ESPECTROSCOPIA RMN; ESTERASAS; ESTERASE; ESTERASES; EXSUDATION; EXUDACION; EXUDATION; FOSFATOS; FOSFORO; Fundamental and applied biological sciences. Psychology; Hydrolysis; ISOTOPE LABELLING; MARCACION CON ISOTOPOS; MARQUAGE ISOTOPIQUE; Membrane and intracellular transports; Molecular and cellular biology; NMR SPECTROSCOPY; NUTRIENT TRANSPORT; Perfusion; PHOSPHATASES; PHOSPHATE; PHOSPHATES; PHOSPHORE; PHOSPHORUS; Plant cells; Plants; Protoplasts; SPECTROSCOPIE RMN; TRANSLOCACION; TRANSLOCATION; TRANSPORT DES SUBSTANCES NUTRITIVES; TRANSPORTE DE NUTRIENTES; XILEMA; XYLEM; XYLEME; Acer pseudoplatanus; Xylem; Enzyme; Dicotyledones; Choline; Biological transport; Angiospermae; Plasma membrane; Organic phosphate; Spermatophyta; NMR spectrometry; Aceraceae
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.87.11.4280

Phosphocholine (PC) is an abundant primary form of organic phosphate that is transported in plant xylem sap. Addition of PC to the perfusate of compressed Pi-starved sycamore cells monitored by31P NMR spectroscopy resulted in an accumulation of PC and all the other phosphate esters in the cytoplasmic compartment. Addition of hemicholinium-3, an inhibitor of choline uptake, to the perfusate inhibited PC accumulation but not inorganic phosphate (Pi). When the Pi-starved cells were perfused with a medium containing either Pior PC, the resulting Pidistribution in the cell was the same. Addition of choline instead of PC to the perfusate of compressed cells resulted in an accumulation of PC in the cytoplasmic compartment from choline kinase activity. In addition, PC phosphatase activity has been discovered associated with the cell wall. These results indicate that PC was rapidly hydrolyzed outside the cell and that choline and Pientered the cytosolic compartment where choline kinase re-forms PC.