The role of ABC proteins for the transverse dynamics of cholesterol in membranes I

Cholesterol is an essential component of biological membranes. Besides its role to stabilize membrane structure, cholesterol plays also a functional role in various membrane processes. The transbilayer movement of cholesterol between both halves of the membrane is an important step of the cellular cholesterol transport. In this process transport proteins of the ATP-Binding Cassette(ABC) protein family are involved, however, their molecular function is unknown. The role of ABC proteins for the transport of cholesterol across plasma membranes of eucaryotic cells will be investigated in the present project. For that, experiments will be performed (i) on model membranes, (ii) on biological membranes expressing the related proteins and (iii) on proteoliposomes. The transbilayer mobility of cholesterol will be investigated by using labeled analogues of cholesterol and biochemical and spectroscopical assays.