title: Loss of resealing ability in erythrocyte membranes. Effect of divalent cations and spectrin release.
abstract: Washed human erythrocyte membranes can recover impermeability to macromolecules upon warming in solutions of sufficient ionic strength. This ability is rapidly lost from most ghost preparations in dilute salt solution at temperatures of 15 degrees C of higher. Divalent cations both reseal ghosts in the absence of high ionic strength and prevent loss of resealing ability. The effective concentrations are 40 micron for Ca2+ and 200 micron for Mg2+. The loss of resealing ability is associated with the release of spectrin polypeptides from the inner surface of the membrane. In ghost preparations that have not become irreversibly leaky, or in the presence of Ca2+, loss of spectrin does not occur. These results suggest that an intact spectrin netwoek is required for resealing to macromolecules, and divalent cations stabilize this network. In light of this information, the effect of temperature on resealing kinetics is described.
mesh_terms: D002118:Calcium / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008565:Membrane Proteins / Q000502:physiology*; D009994:Osmolar Concentration; D013049:Spectrin / Q000502:physiology*; D013696:Temperature
chemical_list: D008565:Membrane Proteins; D013049:Spectrin; D008274:Magnesium; D002118:Calcium