Evidence for electro-induced membrane defects assessed by lateral mobility measurement of a GPi anchored protein.

Electrotransfer is a method by which molecules can be introduced into living cells via plasma membrane electropermeabilization. Here, we show that electropermeabilization affects the lateral mobility of Rae-1, a GPi anchored protein. Our results suggest that 10-20 % of the membrane surface is occupied by defects or pores and that these structures propagate rapidly (<1 min) over the cell surface. Electrotransfer of plasmid DNA (pDNA) also affects the lateral mobility of Rae-1. Furthermore, we clearly show that, once inserted into the plasma membrane, pDNA is completely immobile and excludes Rae-1; this indicates that the pDNA molecules are tightly packed together to form aggregates occupying at least the outer leaflet of the plasma membrane.