Transmembrane mobility and distribution of phospholipids in the membrane of mouse beta-thalassaemic red blood cells.
Using spin-labelled lipid analogues, the transmembrane mobility and distribution of phospholipids in normal and beta-thalassaemic murine red blood cells were investigated. The velocities of spin-labelled phosphatidylserine (PS*) and spin-labelled phosphatidylethanolamine (PE*) active transport into the inner leaflet were not significantly different between normal and pathological cells. The stationary distribution of PE* in thalassaemic erythrocytes (79.5 +/- 2.0% inside) differed from that of control cells (91.1 +/- 1.6% inside), while that of PS* was unaffected. In thalassaemic cells the passive diffusion of spin-labelled phosphatidylcholine (PC*) was accelerated 4-fold and its stationary distribution was shifted to 34.5 +/- 2.3% inside compared to 19.5 +/- 1.6% in control cells. Spin-labelled sphingomyelin (SM*), which showed no inward movement in normal cells, diffused partially towards the inner leaflet of thalassaemic erythrocyte membranes. These results indicate that modifications of the transverse lipid organisation in beta-thalassaemic red blood cells are due to changes in passive diffusion movements, and not to changes in aminophospholipid translocase activity.
Institut de Biologie Physico-Chimique, Paris, France.
P
P
Müller
A
A
Zachowski
Y
Y
Beuzard
P F
PF
Devaux
D000818:Animals; D001692:Biological Transport; D002463:Cell Membrane Permeability; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane / Q000378:metabolism*; D051379:Mice; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D013109:Sphingomyelins / Q000378:metabolism; D013113:Spin Labels; D017086:beta-Thalassemia / Q000378:metabolism*
D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D010743:Phospholipids; D013109:Sphingomyelins; D013113:Spin Labels