Lateral mobility of phospholipids in the external and internal leaflets of normal and hereditary spherocytic human erythrocytes

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22 Scopus citations

Abstract

The lateral diffusion coefficients (D) and the mobile fractions of the fluorescent phospholipid N-(7-nitro-benz-2-oxa-1,3-diazol-4-yl)phosphatidylethanolamine (NBD-PE) and of membrane proteins labelled with fluorescein isothiocyanate, were measured by fluorescence photobleaching recovery on erythrocytes from healthy persons and from a hereditary spherocytosis patient. Measurements of lipid probe mobility were performed on ghosts labelled by NBD-PE exclusively at the external monolayer, or at both sides of the membrane. Our results indicate the following: (1) The mean values and the temperature dependence of D are different at the external and internal membrane leaflets. (2) In both normal and HS ghosts the mobile fraction of NBD-PE in the external monolayer does not depend significantly on temperature. On the other hand, the mobile fraction in the internal monolayer is reduced as the temperature is decreased. (3) At low temperatures, the mobile fraction of NBD-PE in the internal monolayer of spherocytic ghosts is significantly lower than the mobile fraction in the internal monolayer of normal ghosts. (4) No differences were observed between the mobilities of membrane proteins in normal and in spherocytic ghosts. However, differences were observed between the two cell populations in the temperature-dependence of the intrinsic fluorescence of unlabelled membrane proteins. The implications of these results for membrane phospholipid asymmetry and for cytoskeletal interactions with the internal lipid monolayer are discussed.

Original languageEnglish
Pages (from-to)283-290
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Volume775
Issue number3
DOIs
StatePublished - 5 Sep 1984

Keywords

  • Erythrocyte membrane
  • Fluorescence
  • Lateral diffusion
  • Phospholipid
  • Photobleaching
  • Spherocytosis

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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