The Arc system consists of a membrane-associated histidine kinase, ArcB, and a response regulator, ArcA. Mutations in the arc genes cause derepression of several genes and repression of a relatively short list of others, indicating that phosphorylated ArcA is both a repressor and activator of gene transcription under anaerobic conditions. It has been possible to conclude that the Arc system is responsible for:

• Anaerobic repression of genes for:
  Citric acid cycle enzymes
  Glyoxylate cycle enzymes
  Several dehydrogenases for aerobic growth
  Fatty acid oxidation enzymes
  Cytochrome o oxidase
• Anaerobic induction of gene for:
  Pyruvate formate-lyase
• Induction in low oxygen of the genes for
  Cytochrome d oxidase and cobalamin synthesis and (along with FNR), the pyruvate formate-lyase gene.

In E.coli, the ArcB protein has three cytoplasmic domains: a primary transmitter domain (H1) containing a conserved His292, a receiver domain (D1) containing a conserved Asp576, and a secondary transmitter domain (H2) containing a conserved His717. ArcB thus belongs to the tripartite hybrid sensor kinase subfamily, which also includes BarA, EvgS, and TorS of E. coli, BvgS of Bordetella pertussis, LemA of Pseudomonas syringae pv. syringae, and RteA of Bacteroides thetaiotaomicron (5).

Schematic representation of ArcB, ArcB' and ArcA in Haemophilus ducreyi

The domain organizations of ArcB and ArcA in E.coli, Haemophilus influenzae and Haemophilus ducreyi

Proposed Model for signal transduction by the ArcA/ArcB regulatory system in Haemophilus ducreyi

ArcB Sequence Alignment

 
References:

1. Georgellis, D., O. Kwon, P. De Wulf, and E. C. C. Lin. 1998. Signal Decay through a Reverse Phosphorelay in the Arc Two-component Signal Transduction System. J. Biol. Chem. 273(49):32864-32869.
2. Georgellis, D., O. Kwon, and E. C. C. Lin. 1999. Amplification of Signaling Activity of the Arc Two-component System of Escherichia coli by Anaerobic Metabolites. AN IN VITRO STUDY WITH DIFFERENT PROTEIN MODULES. J. Biol. Chem. 274(50):35950-35954.
3. Iuchi, S., and E. Lin. 1992. Mutational analysis of signal transduction by ArcB, a membrane sensor protein responsible for anaerobic repression of operons involved in the central aerobic pathways in Escherichia coli. J. Bacteriol. 174(12):3972-3980.
4. Iuchi, S., and E. C. Lin. 1988. arcA (dye), a global regulatory gene in Escherichia coli mediating repression of enzymes in aerobic pathways. proceedings of the national academy of sciences of the united states of america. 85(6):1888-92.
5. Kwon, O., D. Georgellis, and E. C. C. Lin. 2000. Phosphorelay as the Sole Physiological Route of Signal Transmission by the Arc Two-Component System of Escherichia coli. J. Bacteriol. 182(13):3858-3862.
6. Tsuzuki, M., K. Ishige, and T. Mizuno. 1995. Phosphotransfer circuitry of the putative multi-signal transducer, ArcB, of Escherichia coli: in vitro studies with mutants. molecular microbiology. 18(5):953-62.
   

This analysis was prepared by Gary Xie, and Staff. Please direct questions concerning this analysis to Gary Xie.