Changes in membrane and surface potential explain the opposite effects of low ionic strength on the two lysine transporters of human erythrocytes.

The Journal of Biological Chemistry
R Devés, S Angelo

Abstract

The sucrose-induced stimulation of lysine influx in human erythrocytes has been attributed to the removal of a competitive inhibition exerted by Na+ on system y+ (Young, J. D., Fincham, D. A., and Harvey, C. M. (1991) Biochim. Biophys. Acta 1070, 111-118). We have reexamined this phenomenon separating the contribution of the two cationic amino acid transporters present in these cells (system y+ and system y+L). NaCl replacement with sucrose increased influx through system y+L, but decreased influx through system y+. We conclude that 1) the inhibition of system y+ is a response to the membrane depolarization that results from chloride removal, and 2) the stimulation of system y+L is due to the enhancement of the negative surface potential. Consistently, lysine influx through system y+L (in sucrose medium) was reduced by Na+, K+, Li+, and choline (K0.5 = 25-34 mM), the effect reaching a maximum at 35-40% of the original flux. Divalent cations (Ca2+ and Mg2+) were also inhibitory, but lower concentrations were required (K0.5 1.1-1.8 mM). The finding that sucrose stimulates uptake through changes in the surface potential explains similar effects observed in other cells with various cationic substrates.

References

Apr 1, 1976·Journal of Theoretical Biology·A P Theuvenet, G W Borst-Pauwels
Mar 1, 1991·The Journal of Physiology·I BernhardtJ C Ellory
Jul 1, 1969·Proceedings of the National Academy of Sciences of the United States of America·H N ChristensenE L Thomas

❮ Previous
Next ❯

Citations

Apr 24, 2003·European Journal of Biochemistry·Maria G SignorelloGiuliana Leoncini
Mar 27, 2001·Annual Review of Pharmacology and Toxicology·B K RanaP A Insel
Mar 27, 2001·Annual Review of Pharmacology and Toxicology·R M BreyerM D Breyer
Apr 30, 2004·Photochemistry and Photobiology·Saskia A G LambrechtsJohan W M Lagerberg
Jan 6, 2004·Fundamental & Clinical Pharmacology·N Tugba DurluInci Sahin-Erdemli
Jan 16, 2008·Physiological Reviews·Stefan Bröer
Nov 18, 2000·American Journal of Physiology. Cell Physiology·V Dall'AstaG C Gazzola
Nov 21, 2007·Nephron. Experimental Nephrology·Mariana Alves de Sá SiqueiraTatiana M C Brunini
May 23, 2001·Archives of Biochemistry and Biophysics·S S WolfM Schweizer

❮ Previous
Next ❯

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.