Bacterial signal transduction network in a genomic perspective


  • Michael Y. Galperin

    Corresponding author
    1. National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA.
      *E-mail; Tel. (+1) 301 435 5910; Fax (+1) 301 435 7794.
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  • Dedicated to the memory of Moshe Benziman, who discovered the c-diGMP, diguanylate cyclases and c-diGMP phosphodiesterases. Passed away 10 September 2003.

*E-mail; Tel. (+1) 301 435 5910; Fax (+1) 301 435 7794.


Bacterial signalling network includes an array of numerous interacting components that monitor environmental and intracellular parameters and effect cellular response to changes in these parameters. The complexity of bacterial signalling systems makes comparative genome analysis a particularly valuable tool for their studies. Comparative studies revealed certain general trends in the organization of diverse signalling systems. These include (i) modular structure of signalling proteins; (ii) common organization of signalling components with the flow of information from N-terminal sensory domains to the C-terminal transmitter or signal output domains (N-to-C flow); (iii) use of common conserved sensory domains by different membrane receptors; (iv) ability of some organisms to respond to one environmental signal by activating several regulatory circuits; (v) abundance of intracellular signalling proteins, typically consisting of a PAS or GAF sensor domains and various  output  domains;  (vi)  importance  of secondary messengers, cAMP and cyclic diguanylate; and (vii) crosstalk between components of different signalling pathways. Experimental characterization of the novel domains and domain combinations would be needed for achieving a better understanding of the mechanisms of signalling response and the intracellular hierarchy of different signalling pathways.