Figure 3. Schematic model of the actions of 20 auxiliary proteins on the regulation of type 1 pili.

The inverted repeat left and right (IRL and IRR) are shown as open boxes. Binding sites for integration host factor (IHF I and II) and leucine-responsive protein (Lrp1, 2, and 3) are also represented as open boxes. Genes are displayed as black boxes and the promoters are shown as bent black arrows. The dark gray arrows correspond to FimB and the light gray arrows are for FimE. Black arrows signify an effect on the fimS element. Solid green arrows indicate confirmed binding associated with stimulatory effects, whereas dashed green arrows indicate presumed stimulatory effects. Solid red arrows indicate confirmed binding associated with repressing effects, whereas dashed red arrows indicate presumed repressing effects.