ETHANOL STIMULATES EXPRESSION OF FUNCTIONAL H-ATPASE IN SF9 CELLS(,K+)

The baculovirus expression system is suitable for functional expressio n of gastric H+,K+-ATPase. Expression of functional H+,K+-ATPase in Sf 9 cells is accompanied by synthesis of large amounts of non-functional subunits. When H+,K+-ATPase is synthesised in the presence of 150-250 mM ethanol in the culture medium, two to threefold higher levels of f unctional H+,K+-ATPase are produced due to the formation of more funct ional subunits rather than to an increase of subunits per se. The cata lytical properties of the ethanol-produced H+,K+-ATPase are indistingu ishable from control preparations. The mechanism by which ethanol stim ulates the formation of functional H+,K+-ATPase probably involves a di rect effect on the physical properties of Sf9 membranes. In addition t here also might be an indirect effect through ethanol inducible stress proteins acting as molecular chaperones. (C) 1995 Academic Press, Inc .