Probing the structure and dynamics of caveolin-1 in a caveolae-mimicking asymmetric lipid bilayer model

Caveolin-1 is the principle membrane protein of caveolae and plays an important role in various cellular processes. The protein contains two helices (H1 and H2) connected by a three-residue break. Although caveolin-1 is assumed to adopt a U-shaped conformation in the transmembrane domain, with both the N-terminus and C-terminus exposed to the cytoplasm, the structure and dynamics of caveolin-1 in membranes are still unclear. Here, we performed six molecular dynamics simulations to characterize the structure and dynamics of caveolin-1 (residues D82-S136; Cav1(82-136)) in a caveolae-mimicking asymmetric lipid bilayer. The simulations reveal that the structure of the caveolin scaffolding domain of caveolin-1 is dynamic, as it could be either fully helical or partly unstructured. Cav1(82-136) inserts into the inner leaflet of the asymmetric lipid bilayer with a stable U-shaped conformation and orients almost vertical to the bilayer surface. The simulations also provide new insights into the effects of caveolin-1 on the morphology of caveolae and the possible interacting site of cholesterol on caveolin-1.