Figure 7
Dual Aβ binding sites in Abcg4. The Abcg4 dimer is comprised of two monomers (gray surface) that form two nearly identical binding sites for Aβ (green mesh, panel A). This view of the membrane-spanning domain from the intracellular aspect shows two Aβ molecules (green mesh) occupying the binding clefts. The membrane-spanning domain viewed from the side, panel B, shows the competitive binding mode of desmosterol (yellow surface) with Aβ (red mesh) while another Aβ molecule is present in the opposite binding cleft (green mesh). This configuration explains the observed preference for Aβ (two sites) and inhibitory effect of sterols on Aβ efflux.
