Lipid Localization in Bacterial Cells through Curvature-Mediated Microphase Separation

摘要: Although many proteins are known to localize in bacterial cells, for the most part our understanding of how such localization takes place is limited. Recent evidence that phospholipid cardiolipin localizes poles rod-shaped bacteria suggests targeting some may rely on heterogeneous distribution membrane lipids. Membrane curvature has been proposed as a factor polar high-intrinsic-curvature lipids, but small size lipids compared dimensions cell means single molecules cannot stably localize. At other extreme, phase separation energetically favors domain at one pole. We have physical mechanism which osmotic pinning wall naturally produces microphase separation, i.e., lipid domains finite size, whose aggregate sensitivity can support spontaneous and stable both poles. Here, we demonstrate variations strength also act strong mechanism, agreement with observations relocalization from septum during sporulation bacterium Bacillus subtilis. In addition, rigorously determine relationship between domain-size including effects entropy, quantify domain-domain interactions. Our model predicts critical concentration below will not form hence take place. This observation consistent recent experiments showing Escherichia coli cells reduced concentrations, osmoregulatory protein ProP fail