Membrane Protein Transfer from Human Erythrocyte Ghosts to Liposomes Containing an Artificial Boundary Lipid

When human erythrocyte ghost was exposed to a liposome that contains an artificial boundary lipid (1, 2-dimyristoylamido-l, 2-deoxyphosphatidylcholine, coded as D₁₄DPC), various kinds of membrane proteins and several lipids effectively transferred from the ghost to the liposome. The amount of proteins transferred increased with an increase in the D₁₄DPC content of the liposome. The SDS-PAGE analysis revealed the bands at 88 kDa, 74 kDa and 55 kDa in the liposome after the exposure. No erythrocyte proteins larger than 88 kDa were detected. Transfer of AChE and band 3 was detected by using the enzymatic activity of AChE and a fluorescence probe specific to band 3. For the membrane protein transfer, an induction period was usually observed. The duration of the induction period was almost same for both of proteins, AChE and band 3. However, the transfer efficiency of band 3 was much less than that of AChE. Except the membrane proteins, a detectable amount of cholesterol also transferred from the ghost to the liposome. On the other hand, a significant amount of phospholipids simultaneously transferred from the liposome to the ghost.