Micrometric segregation of fluorescent membrane lipids: relevance for endogenous lipids and biogenesis in erythrocytes

J Lipid Res. 2013 Apr;54(4):1066-76. doi: 10.1194/jlr.M034314. Epub 2013 Jan 14.

Abstract

Micrometric membrane lipid segregation is controversial. We addressed this issue in attached erythrocytes and found that fluorescent boron dipyrromethene (BODIPY) analogs of glycosphingolipids (GSLs) [glucosylceramide (BODIPY-GlcCer) and monosialotetrahexosylganglioside (GM1BODIPY)], sphingomyelin (BODIPY-SM), and phosphatidylcholine (BODIPY-PC inserted into the plasma membrane spontaneously gathered into distinct submicrometric domains. GM1BODIPY domains colocalized with endogenous GM1 labeled by cholera toxin. All BODIPY-lipid domains disappeared upon erythrocyte stretching, indicating control by membrane tension. Minor cholesterol depletion suppressed BODIPY-SM and BODIPY-PC but preserved BODIPY-GlcCer domains. Each type of domain exchanged constituents but assumed fixed positions, suggesting self-clustering and anchorage to spectrin. Domains showed differential association with 4.1R versus ankyrin complexes upon antibody patching. BODIPY-lipid domains also responded differentially to uncoupling at 4.1R complexes [protein kinase C (PKC) activation] and ankyrin complexes (in spherocytosis, a membrane fragility disease). These data point to micrometric compartmentation of polar BODIPY-lipids modulated by membrane tension, cholesterol, and differential association to the two nonredundant membrane:spectrin anchorage complexes. Micrometric compartmentation might play a role in erythrocyte membrane deformability and fragility.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Boron Compounds / chemistry
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Cholesterol / chemistry
  • Chromatography, Thin Layer
  • Erythrocytes / drug effects
  • Erythrocytes / metabolism*
  • Erythrocytes / ultrastructure
  • Glycosphingolipids / chemistry
  • Heterocyclic Compounds, 3-Ring / chemistry
  • Humans
  • Membrane Lipids / chemistry*
  • Microscopy, Electron, Scanning
  • Phosphatidylcholines / chemistry
  • Sphingomyelins / chemistry
  • beta-Cyclodextrins / pharmacology

Substances

  • 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene
  • BODIPY-PC
  • Boron Compounds
  • Glycosphingolipids
  • Heterocyclic Compounds, 3-Ring
  • Membrane Lipids
  • Phosphatidylcholines
  • Sphingomyelins
  • beta-Cyclodextrins
  • methyl-beta-cyclodextrin
  • Cholesterol