  We investigate a mechanism for the polar localization of proteins in
bacteria. We focus on the MinCD/DivIVA system regulating division site
placement in the rod-shaped bacterium Bacillus subtilis. Our model relies on a
combination of geometric effects and reaction-diffusion dynamics to direct
proteins to both cell poles, where division is then blocked. We discuss
similarities and differences with related division models in Escherichia coli
and also develop extensions of the model to asymmetric polar protein
localization. We propose that our mechanism for polar localization may be
employed more widely in bacteria, especially in outgrowing spores, which do not
possess any pre-existing polar division apparatus from prior division events.
