The Gram-negative bacterium Caulobacter crescentus forms a thin polar stalk, which
mediates its attachment to solid surfaces. Whereas stalks remain short (1 µm) in nutrient-rich
conditions, they lengthen dramatically (up to 30 µm) upon phosphate starvation. A long-
standing hypothesis is that the Caulobacter stalk functions as a nutrient scavenging
“antenna” that facilitates phosphate uptake and transport to the cell body. The mechanistic
details of this model must be revisited, given our recent identification of a protein-mediated …