Locations of Mapped Genes:
Synonyms: HydHG Two Component Signal Transduction System
|Superclasses:||Signal transduction pathways|
In E. coli, two-component regulatory systems sense and respond to changes in environmental conditions. In the prototypical system a membrane associated sensor kinase autophosphorylates in response to an environmental signal. The sensor kinase then transfers a phosphoryl group to a response regulator (RR) which, thus activated, effects a response. The majority of RRs in E. coli are transcription factors.
The ZraSR two-component system comprises ZraS - the membrane associated sensor kinase - and ZraR - the cytoplasmic response regulator. ZraSR regulates expression of zraP which encodes a periplasmic zinc-binding protein with a putative role in zinc homeostasis. Growth of E. coli K-12 in the presence of high external zinc or lead concentrations results in increased cellular levels of ZraR which are dependent on the presence of ZraS. Direct sensing of Zn2+ by ZraS has not been shown. [Leonhartsberger01]
At one time this system was known as the HydH/G system since it was thought to be involved in regulation of hydrogenase 3 activity [Stoker89].
Leonhartsberger01: Leonhartsberger S, Huber A, Lottspeich F, Bock A (2001). "The hydH/G Genes from Escherichia coli code for a zinc and lead responsive two-component regulatory system." J Mol Biol 2001;307(1);93-105. PMID: 11243806
Stoker89: Stoker K, Reijnders WN, Oltmann LF, Stouthamer AH (1989). "Initial cloning and sequencing of hydHG, an operon homologous to ntrBC and regulating the labile hydrogenase activity in Escherichia coli K-12." J Bacteriol 1989;171(8);4448-56. PMID: 2666400
Yamamoto05: Yamamoto K, Hirao K, Oshima T, Aiba H, Utsumi R, Ishihama A (2005). "Functional characterization in vitro of all two-component signal transduction systems from Escherichia coli." J Biol Chem 280(2);1448-56. PMID: 15522865
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
MendezOrtiz06: Mendez-Ortiz MM, Hyodo M, Hayakawa Y, Membrillo-Hernandez J (2006). "Genome-wide transcriptional profile of Escherichia coli in response to high levels of the second messenger 3',5'-cyclic diguanylic acid." J Biol Chem 281(12);8090-9. PMID: 16418169
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