FIG. 1.

Circuit elements and signaling logic of the E. coli chemotaxis pathway. Green, components and reactions that augment clockwise flagellar rotation; red, counterclockwise-enhancing elements. Cytoplasmic Che proteins are designated by single letters; MCPs (methyl-accepting chemotaxis proteins) are transmembrane chemoreceptors that modulate the autokinase activity of CheA in response to changes in ligand occupancy and methylation state. The CheB and CheY response regulators are inactive (gray) until phosphorylated. See text for additional details.