24] Analysis of two-component signal transduction systems involved in transcriptional regulation

Abstract

Publisher Summary This chapter discusses the experimental approaches that have been used to assess the function of two component transcriptional regulation systems following the discovery of a new response regulator or kinase gene. Bacteria possess extensive signal transduction networks that function to regulate transcription. These systems are composed of modular domains that interact with one another to process information and effect appropriate responses to changing environmental conditions. Two superfamilies of signal transduction proteins are involved: protein kinases that autophosphorylate themselves at specific histidine residues, and response regulators that use these phosphoryl groups as well as phosphoryl groups from small molecule phosphodonors such as acetyl phosphate to autophosphorylate themselves at a specific aspartate residue. Generally, phosphorylation of the response regulator receiver domain is critical for activity of an associated DNA binding-transcriptional regulation domain. The regulatory circuitry that controls the level of phosphorylation of a given response regulator can be quite complex. Histidine kinases clearly play a central role in this process, both by supplying phosphoryl groups and in some cases by facilitating the removal of these groups. The sensory mechanisms that control histidine kinase activity are, however, poorly understood.