Figure 10.

A model of inhibition of membrane fusion by αS. (A) Formation of a fusion stalk in the absence of αS. Two membranes achieve close proximity, possibly assisted by a docking machine (not drawn). Curvature in at least one of the fusing membranes causes stress in the packing of the lipids (see inset, the red lipids are not ideally packed), which is necessary to enable fusion of the leaflets of the two fusing membranes and the formation of a fusion stalk. (B) Binding of αS to curved membranes seals the packing defects and therefore inhibits the formation of a fusion stalk.