Two-Component Systems, Protein Kinases, and Signal Transduction in Mycobacterium tuberculosis

2005 ◽  
pp. 359-367 ◽  
Keyword(s):  
Signal Transduction ◽  
Mycobacterium Tuberculosis ◽  
Protein Kinases ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

scholarly journals Autoregulation of the MisR/MisS Two-Component Signal Transduction System in Neisseria meningitidis

2006 ◽  
Vol 188 (14) ◽  
pp. 5055-5065 ◽  
Author(s):  
Yih-Ling Tzeng ◽  
Xiaoliu Zhou ◽  
Shaojia Bao ◽  
Shuming Zhao ◽  
Corie Noble ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Neisseria Meningitidis ◽  
Transcriptional Start Site ◽  
Specific Interaction ◽  
Phosphoryl Group ◽  
Start Site ◽  
Protein Fusion ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

ABSTRACT Two-component regulatory systems are involved in processes important for bacterial pathogenesis. The proposed misR/misS (or phoP/phoQ) system is one of four two-component systems of the obligate human pathogen Neisseria meningitidis. Inactivation of this system results in loss of phosphorylation of the lipooligosaccharide inner core and causes attenuation in a mouse model of meningococcal infection. MisR and the cytoplasmic domain of MisS were purified as His6 and maltose binding protein fusion proteins, respectively. The MisS fusion was shown to be autophosphorylated in the presence of ATP, and the phosphoryl group was subsequently transferred to MisR. The phosphotransfer reaction was halted with a MisR/D52A mutation, while a MisS/H246A mutation prevented autophosphorylation. Specific interaction of phosphorylated MisR (MisR∼P) and MisR with the misR promoter was demonstrated by gel mobility shift assays, where MisR∼P exhibited higher affinity than did the nonphosphorylated protein. The transcriptional start site of the misRS operon was mapped, and DNase I protection assays revealed that MisR interacted with a 15-bp region upstream of the transcriptional start site that shared no similarity to binding motifs of other two-component systems. Transcriptional reporter studies suggested that MisR phosphorylation is critical for the autoinduction of the misRS operon. Limited Mg2+ concentration failed to induce expression of the misRS operon, which is the only operon now proven to be under the direct control of the MisRS two-component system. Thus, these results indicate that the meningococcal MisRS system constitutes a functional signal transduction circuit and that both components are critical in the autoregulation of their expression.

Cationic antimicrobial peptides elicit a complex stress response in Bacillus subtilis that involves ECF-type sigma factors and two-component signal transduction systems

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1577-1592 ◽  
Author(s):  
Milla Pietiäinen ◽  
Marika Gardemeister ◽  
Maria Mecklin ◽  
Soile Leskelä ◽  
Matti Sarvas ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Bacillus Subtilis ◽  
Antimicrobial Peptides ◽  
Stress Responses ◽  
Signal Transduction Pathways ◽  
Synthetic Analogue ◽  
Cationic Antimicrobial Peptides ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Stress responses of Bacillus subtilis to membrane-active cationic antimicrobial peptides were studied. Global analysis of gene expression by DNA macroarray showed that peptides at a subinhibitory concentration activated numerous genes. A prominent pattern was the activation of two extracytoplasmic function sigma factor regulons, SigW and SigM. Two natural antimicrobial peptides, LL-37 and PG-1, were weak activators of SigW regulon genes, whereas their synthetic analogue poly-l-lysine was clearly a stronger activator of SigW. It was demonstrated for the first time that LL-37 is a strong and specific activator of the YxdJK two-component systems, one of the three highly homologous two-component systems sensing antimicrobial compounds. YxdJK regulates the expression of the YxdLM ABC transporter. The LiaRS (YvqCE) TCS was also strongly activated by LL-37, but its activation is not LL-37 specific, as was demonstrated by its activation with PG-1 and Triton X-100. Other strongly LL-37-induced genes included yrhH and yhcGHI. Taken together, the responses to cationic antimicrobial peptides revealed highly complex regulatory patterns and induction of several signal transduction pathways. The results suggest significant overlap between different stress regulons and interdependence of signal transduction pathways mediating stress responses.

Mycobacterium tuberculosis Two-Component Systems and implications in novel vaccines and drugs

2012 ◽  
Vol 22 (1) ◽  
pp. 37-52 ◽  
Author(s):  
Pei Fu Zhou ◽  
Quan Xin Long ◽  
Ye Xin Zhou ◽  
Hong Hai Wang ◽  
Jianping Xie
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

scholarly journals The ChrSA and HrrSA Two-Component Systems Are Required for Transcriptional Regulation of thehemAPromoter in Corynebacterium diphtheriae

2016 ◽  
Vol 198 (18) ◽  
pp. 2419-2430 ◽  
Author(s):  
Jonathan M. Burgos ◽  
Michael P. Schmitt
Keyword(s):  
Signal Transduction ◽  
Kinase Activity ◽  
Content Type ◽  
Component Systems ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Two Component Systems ◽  
Signal Transduction Systems

ABSTRACTCorynebacterium diphtheriaeutilizes heme and hemoglobin (Hb) as iron sources for growth in low-iron environments. InC. diphtheriae, the two-component signal transduction systems (TCSs) ChrSA and HrrSA are responsive to Hb levels and regulate the transcription of promoters forhmuO,hrtAB, andhemA. ChrSA and HrrSA activate transcription at thehmuOpromoter and repress transcription athemAin an Hb-dependent manner. In this study, we show that HrrSA is the predominant repressor athemAand that its activity results in transcriptional repression in the presence and absence of Hb, whereas repression ofhemAby ChrSA is primarily responsive to Hb. DNA binding studies showed that both ChrA and HrrA bind to thehemApromoter region at virtually identical sequences. ChrA binding was enhanced by phosphorylation, while binding to DNA by HrrA was independent of its phosphorylation state. ChrA and HrrA are phosphorylatedin vitroby the sensor kinase ChrS, whereas no kinase activity was observed with HrrSin vitro. Phosphorylated ChrA was not observedin vivo, even in the presence of Hb, which is likely due to the instability of the phosphate moiety on ChrA. However, phosphorylation of HrrA was observedin vivoregardless of the presence of the Hb inducer, and genetic analysis indicates that ChrS is responsible for most of the phosphorylation of HrrAin vivo. Phosphorylation studies strongly suggest that HrrS functions primarily as a phosphatase and has only minimal kinase activity. These findings collectively show a complex mechanism of regulation at thehemApromoter, where both two-component systems act in concert to optimize expression of heme biosynthetic enzymes.IMPORTANCEUnderstanding the mechanism by which two-component signal transduction systems function to respond to environmental stimuli is critical to the study of bacterial pathogenesis. The current study expands on the previous analyses of the ChrSA and HrrSA TCSs in the human pathogenC. diphtheriae. The findings here underscore the complex interactions between the ChrSA and HrrSA systems in the regulation of thehemApromoter and demonstrate how the two systems complement one another to refine and control transcription in the presence and absence of Hb.

The mechanism of signal transduction by two-component systems

2010 ◽  
Vol 20 (6) ◽  
pp. 763-771 ◽  
Author(s):  
Patricia Casino ◽  
Vicente Rubio ◽  
Alberto Marina
Keyword(s):  
Signal Transduction ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems
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