title: Metabolic dependence of the fluidity of intact erythrocyte membrane.
abstract: The motion of spin labeled phosphatidylcholine embedded in the lipid bilayer of erythrocyte membrane increased in association with metabolic ATP-depletion. The fluidity change was reversed by subsequent ATP-replenishment. However, levels of cellular 1,2-diacylglycerol, GSH or intracellular Ca2+ contributed little to the fluidity change. Temperature dependence of the fluidity indicated the disappearance of inflection points in ATP-depleted cells, thereby suggesting alterations in protein-lipid interactions. The fluidity change was also reproduced with oxidizing agents which cross-link spectrin. We suggest that the lipid phase state of membrane is maintained by protein-lipid interactions which depend on the metabolic state of the cells, particularly ATP levels.
mesh_terms: D000255:Adenosine Triphosphate / Q000097:blood; D002118:Calcium / Q000097:blood; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane / Q000502:physiology*; D005978:Glutathione / Q000097:blood; D006801:Humans; D008560:Membrane Fluidity; D010713:Phosphatidylcholines; D013997:Time Factors
chemical_list: D010713:Phosphatidylcholines; D000255:Adenosine Triphosphate; D005978:Glutathione; D002118:Calcium