Geometric protein localization cues in bacterial cells

•Bacteria localize proteins to distinct subcellular locations.•Membrane curvature (convex or concave) can be a beacon to recruit certain proteins.•In vitro assays using curved membranes can reveal how proteins sense curvature.

Bacterial cells are highly organized at a molecular level. Understanding how specific proteins localize to their proper subcellular address has been a major challenge in bacterial cell biology. One mechanism, which appears to be increasingly more common, is the use of 'geometric cues' for protein localization. In this model, certain shape-sensing proteins recognize, and preferentially embed into, either negatively or positively curved (concave or convex, respectively) membranes. Here, we review examples of bacterial proteins that reportedly localize by sensing geometric cues and highlight emerging mechanistic understandings of how proteins may recognize subtle differences in membrane curvature.