Finding the corners in a cell.

The bacterial cell is well-organized and many proteins are confined to regions such as midcell or cell poles. These areas are not separated from each other by membranes, and therefore bacteria must rely on basic biophysical processes to localize proteins within their cytoplasmic space. The conserved protein DivIVA accumulates at cell poles and cell division sites of Gram-positive bacteria. It turns out that this protein binds specifically to concave membranes. These negatively curved membrane surfaces occur at the base of the cell division septum and the cell poles. How DivIVA recognizes this topological characteristic is yet unclear, but whole-cell Monte-Carlo simulations suggest that a few basic rules can explain why this protein accumulates at negatively curved membranes.