title: Evolution of prokaryotic two-component systems: insights from comparative genomics.
abstract: Two-component systems (TCSs) are diverse and abundant signal transduction pathways found predominantly in prokaryotes. This review focuses on insights into TCS evolution made possible by the sequencing of whole prokaryotic genomes. Typical TCSs comprise an autophosphorylating protein (a histidine kinase), which transfers a phosphoryl group onto an effector protein (a response regulator), thus modulating its activity. Histidine kinases and response regulators are usually found encoded as pairs of adjacent genes within a genome, with multiple examples in most prokaryotes. Recent studies have shed light on major themes of TCS evolution, including gene duplication, gene gain/loss, gene fusion/fission, domain gain/loss, domain shuffling and the emergence of complexity. Coupled with an understanding of the structural and biophysical properties of many TCS proteins, it has become increasingly possible to draw inferences regarding the functional consequences of such evolutionary changes. In turn, this increase in understanding has the potential to enhance both our ability to rationally engineer TCSs, and also allow us to more powerfully correlate TCS evolution with behavioural phenotypes and ecological niche occupancy.
authors.affiliation: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Ceredigion, UK. dew@aber.ac.uk
authors.forename: David E
authors.initials: DE
authors.lastname: Whitworth
authors.forename: Peter J A
authors.initials: PJ
authors.lastname: Cock
mesh_terms: D000222:Adaptation, Physiological; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D020440:Gene Duplication; D050939:Gene Fusion; D023061:Gene Order; D023281:Genomics; D000071677:Histidine Kinase; D010802:Phylogeny; D054730:Protein Interaction Domains and Motifs / Q000235:genetics*; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000235:genetics*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase