Effects of proteins on phospholipid vesicle aggregation and lipid vesicle-monolayer interactions

✍ Scribed by Shinpei Ohki; Kenneth Leonards

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 706 KB
• Volume: 31
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(82)90066-4

✦ Synopsis

The effects of proteins on divalent cation-induced phospholipid vesicle aggregation and phospholipid vesicle-monolayer membrane interactions (fusion) were examined. Glycophorin (from human erythrocytes) suppressed the membrane interactions more than N-2 protein (from human brain myelin) when these proteins were incorporated into acidic phospholipid vesicle membranes. The threshold concentrations of divalent cations which induced vesicle aggregation were increased by protein incorporation, and the rate of vesicle aggregation was reduced. A similar inh~itory effect by the proteins, incorporated into lipid vesicle membranes, was observed for Ca~+-induced lipid vesicle-rnonolayer interactions. However, when these proteins were incorporated only in the acidic phospholipid monolayers, the interaction (fusion) of the lipid vesicle-monolayer membranes, induced by divalent cations, was not appreciably altered by the presence of the proteins.

In contrast to these two proteins, the presence of synexin in the solution did enhance the Ca~÷qnduced aggregation of phosphatidylserine vesicles, but did not seem to affect the degree of Ca2÷4nduced fusion between phosphatidylserine/phosphatidylcholine (1:1) and phosphatidylserine vesicles and monolayer membranes.