|Gene:||baeR||Accession Numbers: EG11618 (EcoCyc), b2079, ECK2075|
Synonyms: BaeR-Pasp61, BaeR response regulator - phosphorylated
Alternative forms of BaeR-Phosphorylated DNA-binding transcriptional activator: BaeR transcriptional regulator
BaeR has been shown to regulate directly genes involved in drug resistance [Nishino05, Baranova02, Hirakawa03, Hirakawa03a] and indirectly appears to regulate genes involved in several cellular processes, such as flagellum biosynthesis, chemotaxis, and maltose transport [Nishino05].
BaeR belongs to the BaeS/BaeR two-component system [Nagasawa93, Yamamoto05a]. Both genes, baeR, encoding the response regulator, and baeS, encoding the sensor kinase, are located at the end of the operon (mdtABCD-baeSR) regulated by BaeR [Baranova02].
It has been suggested that BaeS senses envelope disorder [Yamamoto08b, Raffa02]. Indole [Hirakawa05, Raffa02] and zinc [Yamamoto08b] have been used as inducers of this disorder. Leblanc et al. identified two flavonoids and also sodium tungstate as novel inducers to BaeSR [Leblanc11]. These new inducers are natural substrates of the MdtABC efflux pump, and they lead to much stronger induction of the BaeST response in an mdtA efflux pump mutant, while indole does not [Leblanc11]. As a consequence of this sensing, BaeS is autophosphorylated, followed by the transfer of the phosphate group to BaeR [Nagasawa93], which is converted to an active form [Baranova02] that appears to recognize and bind a DNA sequence with a direct repeat symmetry [Yamamoto08b].
BaeR exhibits high degrees of sequence similarity with the transcriptional regulators OmpR and PhoB [Nagasawa93] and belongs to the OmpR subfamily whose members contain a DNA-binding motif in the C-terminal domain [Nagasawa93].The BaeSR, PhoBR, and CreBC two-component systems have been shown to interact in the regulation of gene expression [Nishino05]. BaeR suppresses envZ and phoR/creC mutations [Nagasawa93].
The crystal structure of the unphosphorylated dimeric form of BaeR has been determined [Choudhury13].
BaeR: "bacterial adaptive response, response-regulator " [Nagasawa93].
An integrated transcriptomic study of the extracytoplasmic stress response, which detects and responds to alterations of the bacterial envelope, was performed by Bury-Moré et al. (2009). They investigated the interconnections and dynamics between Bae, Cpx, Psp, Rcs, and σE pathways and showed that these pathways can be activated simultaneously in response to exogenous or endogenous stimulation, while natural environmental stimuli provoke bacterial modifications that lead to multiple pathway responses [BuryMone09].
Each of these responses might be specialized to ensure a specific aspect of envelope biogenesis and maintenance; on the other hand, CpxR could have a role as a modulator of the response by integrating other endogenous signals. Bury-Moré et al. concluded that all five pathways are needed to mount a full response to extracytoplasmic stress [BuryMone09].
Gene Citations: [Nagakubo02]
|Map Position: [2,162,300 -> 2,163,022] (46.6 centisomes)||Length: 723 bp / 240 aa|
Molecular Weight: 27.656 kD (from nucleotide sequence)
In Paralogous Gene Group: 121 (40 members)
Reactions known to produce the compound:
|Biological Process:||GO:0006351 - transcription, DNA-templated [Baranova02]|
|Cellular Component:||GO:0005829 - cytosol|
|MultiFun Terms:||information transfer → RNA related → Transcription related|
|regulation → type of regulation → transcriptional level → activator|
|regulation → type of regulation → transcriptional level → complex regulation → two component regulatory systems (external signal)|
DNA binding site length: 20 base-pairs
Symmetry: Inverted Repeat
Consensus DNA Binding Sequence: CCAtTTtTctccAtAAtTGG
|Conserved-Region||12 -> 125|
10/20/97 Gene b2079 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11618; confirmed by SwissProt match.
Baranova02: Baranova N, Nikaido H (2002). "The baeSR two-component regulatory system activates transcription of the yegMNOB (mdtABCD) transporter gene cluster in Escherichia coli and increases its resistance to novobiocin and deoxycholate." J Bacteriol 184(15);4168-76. PMID: 12107134
BuryMone09: Bury-Mone S, Nomane Y, Reymond N, Barbet R, Jacquet E, Imbeaud S, Jacq A, Bouloc P (2009). "Global analysis of extracytoplasmic stress signaling in Escherichia coli." PLoS Genet 5(9);e1000651. PMID: 19763168
Hirakawa03: Hirakawa H, Nishino K, Hirata T, Yamaguchi A (2003). "Comprehensive studies of drug resistance mediated by overexpression of response regulators of two-component signal transduction systems in Escherichia coli." J Bacteriol 185(6);1851-6. PMID: 12618449
Hirakawa03a: Hirakawa H, Nishino K, Yamada J, Hirata T, Yamaguchi A (2003). "Beta-lactam resistance modulated by the overexpression of response regulators of two-component signal transduction systems in Escherichia coli." J Antimicrob Chemother 52(4);576-82. PMID: 12951338
Leblanc11: Leblanc SK, Oates CW, Raivio TL (2011). "Characterization of the induction and cellular role of the BaeSR two-component envelope stress response of Escherichia coli." J Bacteriol 193(13);3367-75. PMID: 21515766
Nagakubo02: Nagakubo S, Nishino K, Hirata T, Yamaguchi A (2002). "The putative response regulator BaeR stimulates multidrug resistance of Escherichia coli via a novel multidrug exporter system, MdtABC." J Bacteriol 184(15);4161-7. PMID: 12107133
Nishino05: Nishino K, Honda T, Yamaguchi A (2005). "Genome-wide analyses of Escherichia coli gene expression responsive to the BaeSR two-component regulatory system." J Bacteriol 187(5);1763-72. PMID: 15716448
Yamamoto05a: 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
Yamamoto08b: Yamamoto K, Ogasawara H, Ishihama A (2008). "Involvement of multiple transcription factors for metal-induced spy gene expression in Escherichia coli." J Biotechnol 133(2):196-200. PMID: 17884222
GamaCastro08: Gama-Castro S, Jimenez-Jacinto V, Peralta-Gil M, Santos-Zavaleta A, Penaloza-Spinola MI, Contreras-Moreira B, Segura-Salazar J, Muniz-Rascado L, Martinez-Flores I, Salgado H, Bonavides-Martinez C, Abreu-Goodger C, Rodriguez-Penagos C, Miranda-Rios J, Morett E, Merino E, Huerta AM, Trevino-Quintanilla L, Collado-Vides J (2008). "RegulonDB (version 6.0): gene regulation model of Escherichia coli K-12 beyond transcription, active (experimental) annotated promoters and Textpresso navigation." Nucleic Acids Res 36(Database issue);D120-4. PMID: 18158297
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