title: Reconstitution of the transferrin receptor in lipid vesicles. Effect of cholesterol on the binding of transferrin.
abstract: Purified rabbit reticulocyte transferrin receptors were incorporated into phosphatidylcholine vesicles containing varying amounts of cholesterol. The binding of transferrin to the receptor in the reconstituted vesicles had three distinct characteristics: (1) The binding of transferrin exhibited the two components characteristic of transferrin binding to erythroid cells, a saturable, specific component and a nonsaturable, nonspecific component. (2) Transferrin binding exhibited positive cooperativity at low cholesterol/phospholipid (C/P) molar ratios. However, the cooperativity diminished and then disappeared as the C/P molar ratios were increased to the levels found in circulating red blood cells. (3) The amount of specific transferrin binding to the reconstituted vesicles also decreased as the C/P molar ratio was increased. These results indicate that in the reconstituted system the lipid environment plays a significant role in the expression of transferrin receptors.
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000494:pharmacology*; D008081:Liposomes / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D011990:Receptors, Transferrin; D012156:Reticulocytes / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism*
chemical_list: D008081:Liposomes; D010713:Phosphatidylcholines; D011956:Receptors, Cell Surface; D011990:Receptors, Transferrin; D014168:Transferrin; D002784:Cholesterol