Influence of cholesterol on the rotation and self-association of band 3 in the human erythrocyte membrane.
The cholesterol/phospholipid mole ratio (C/P) in the human erythrocyte membrane was varied by incubating cells with liposomes. The rotational mobility of band 3 proteins was measured in these membranes by observing flash-induced transient dichroism of the triplet probe eosin maleimide. Measurements were performed with membranes in which associations of band 3 with cytoskeletal proteins were removed by mild proteolysis with trypsin. It was found that decreasing C/P resulted in a more rapid decay of the flash-induced anisotropy. The anisotropy decay curves were analyzed by curve-fitting procedures, which indicated the existence of different sized small aggregates of band 3. The changes in the decay curves with varying C/P can be explained by an effect of cholesterol on the size distribution of these aggregates. The experiments suggest a possible role of cholesterol in regulating associations between integral membrane proteins.
D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002784:Cholesterol / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000187:drug effects*; D004912:Erythrocytes / Q000187:drug effects*; D006801:Humans; D008560:Membrane Fluidity / Q000187:drug effects; D012399:Rotation; D013696:Temperature; D014357:Trypsin
D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins; D002784:Cholesterol; D014357:Trypsin