A Curvature-Mediated Mechanism for Localization of Lipids to Bacterial Poles
Figure 1
Schematic of Lipid Clustering in Different Membrane Configurations
(A) A homogeneous mixture of two lipid components (type A in blue, B in red) has a high energy because of the abundance of unlike nearest-neighbor pairs, each contributing an energy ε (see Materials and Methods).
(B) Same as (A), except the cell wall has higher curvature; this results in a slight reduction in the energy of lipids of type A, which have higher intrinsic curvature.
(C) A cluster of lipids of type A is accompanied by membrane curvature (∇2h(r)). Though the elastic energy of the membrane increases relative to (A), the formation of clusters eliminates unlike nearest-neighbor pairs and so reduces the total energy.
(D) The same configuration in (C) shifted to a region of cell wall with higher curvature experiences a large reduction in energy, leading to cluster localization at the poles.