REDISTRIBUTION OF LIPID PROBES AT EARLY S TAGES OF BILAYER-LIPID MEMBRANE-FUSION

Redistribution of hydrophobic probes (R18 and dipicrylamine - DPA(-)) through a water gap between two bilayer lipid membranes (BLM) was stud ied. Both probes are widely used for monitoring lipid redistribution i n different cell systems. The donor membrane loaded with the probe was brought into a close contact with the acceptor membrane, and the redi stribution of the probe was recorded by the changes in the admittance of the acceptor membrane. It was shown that DPA(-) easily penetrated t he water gap, whereas R18 was not detected in the acceptor membrane 30 minutes after the close contact formation. After fusion, R18 rapidly spread into the acceptor membrane; hence, only R18 reflects the behavi or of membrane kipids in the fusion process.