PT - JOURNAL ARTICLE AU - Wuichet, Kristin AU - Zhulin, Igor B. TI - Origins and Diversification of a Complex Signal Transduction System in Prokaryotes AID - 10.1126/scisignal.2000724 DP - 2010 Jun 29 TA - Science Signaling PG - ra50--ra50 VI - 3 IP - 128 4099 - http://stke.sciencemag.org/content/3/128/ra50.short 4100 - http://stke.sciencemag.org/content/3/128/ra50.full SO - Sci. Signal.2010 Jun 29; 3 AB - The molecular machinery that controls chemotaxis in bacteria is substantially more complex than any other signal transduction system in prokaryotes, and its origins and variability among living species are unknown. We found that this multiprotein “chemotaxis system” is present in most prokaryotic species and evolved from simpler two-component regulatory systems that control prokaryotic transcription. We discovered, through genomic analysis, signaling systems intermediate between two-component systems and chemotaxis systems. Evolutionary genomics established central and auxiliary components of the chemotaxis system. While tracing its evolutionary history, we also developed a classification scheme that revealed more than a dozen distinct classes of chemotaxis systems, enabling future predictive modeling of chemotactic behavior in unstudied species.