Direct inhibition of phospholipid scrambling activity in erythrocytes by potassium ions

J. L N Wolfs, P. Comfurius, O. Bekers, R. F A Zwaal, K. Balasubramanian, A. J. Schroit, T. Lindhout, E. M. Bevers

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The exposure of phosphatidylserine (PS) at the cell surface plays a critical role in blood coagulation and serves as a macrophage recognition moiety for the engulfment of apoptotic cells. Previous observations have shown that a high extracellular [K+] and selective K+ channel blockers inhibit PS exposure in platelets and erythrocytes. Here we show that the rate of PS exposure in erythrocytes decreases by ~50% when the intracellular [K +] increases from 0 to physiological concentrations. Using resealed erythrocyte membranes, we further show that lipid scrambling is inducible by raising the intracellular [Ca2+] and that K+ ions have a direct inhibitory effect on this process. Lipid scrambling in resealed ghosts occurs in the absence of cell shrinkage and microvesicle formation, processes that are generally attributed to Ca2+-induced lipid scrambling in intact erythrocytes. Thus, opening of Ca2+-sensitive K+ channels causes loss of intracellular K+ that results in reduced intrinsic inhibitory effect of these ions on scramblase activity.

Original languageEnglish (US)
Pages (from-to)314-323
Number of pages10
JournalCellular and Molecular Life Sciences
Volume66
Issue number2
DOIs
StatePublished - Jan 2009

Keywords

  • Erythrocytes
  • Morphology
  • Phosphatidylserine
  • Phospholipid scramblase
  • Potassium ions
  • Resealed ghosts

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Pharmacology
  • Cellular and Molecular Neuroscience
  • Cell Biology

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