Electrogenic and phosphatidylinositol-4-monophosphate-stimulated Cl- transport by Cl- pump in the rat brain.

Rat brain Cl(-)-ATPase was solubilized and reconstituted in asolectin liposomes. Phosphatidylinositol-4-monophosphate increased Cl(-)-ATPase and ATP-dependent Cl- uptake activities in proteoliposomes. The ATP-dependent Cl- uptake was inhibited by a Cl(-)-ATPase inhibitor, ethacrynic acid, and increased at an inside-positive membrane potential or in the presence of a protonophore. These findings suggest that Cl(-)-ATPase is an electrogenic Cl- transporter, or a primary Cl- pump, probably regulated by phosphoinositide turnover in vivo.