This induces a conformational change that alters the function of the effector domains, usually resulting in increased transcription of target genes.

The mechanisms by which this occurs are diverse and include allosteric activation of the effector domain or oligomerization of phosphorylated response regulators.

[1] Histidine kinases are highly specific for their cognate response regulators; there is very little cross-talk between different two-component signaling systems in the same cell.

Once phosphorylated at the receiver domain, the response regulator dimerizes, gains enhanced DNA binding capacity and acts as a transcription factor.

Other enzymatic response regulators include c-di-GMP phosphodiesterases (e.g. VieA in V. cholerae), protein phosphatases and histidine kinases.

[13] The receiver domain undergoes a conformational change as it interacts with an autophosphorylated histidine kinase, and consequently, the response regulator can initiate further reactions along a signaling cascade.

Prominent examples include the chemotaxis regulator CheY, which interacts with flagellar motor proteins directly in its phosphorylated state.