Redistribution of lipid probes at early stages of bilayer lipid membrane fusion.

ABSTRACT

Redistribution of hydrophobic probes (R18 and dipicrylamine DPA-) through a water gap between two bilayer lipid membranes (BLM) was studied. Both probes are widely used for monitoring lipid redistribution in different cell systems. The donor membrane loaded with the probe was brought into a close contact with the acceptor membrane, and the redistribution of the probe, was recorded as changes in the permittance of the acceptor membrane. It was shown that DPA- easily penetrated the water gap, whereas R18 was not detected in the acceptor membrane 30 min after the close contact formation. After fusion, R18 rapidly spread into the acceptor membrane; hence, only R18 reflects the behaviour of membrane lipids in the fusion process.