Overexpression of the ABC Transporter BmrA Within Intracellular Caveolae in Escherichia coli.

We describe here the overproduction and oriented membrane insertion of membrane protein inside intracellular vesicles named heterologous caveolae within E. coli. The method is described with BmrA, a multidrug efflux pump from Bacillus subtilis. BmrA is produced in these vesicles, thanks to the coexpression with the canine caveolin-1β, one of the two isoforms of caveolin-1. Enriched by sucrose gradient, the caveolae-containing fraction allows to probe the ATPase and Hoechst 33342 transport activities, the latter displaying a higher specific activity than the same without caveolin-1β.