Roles of Histidine Kinases and Histidine Phosphatases in Cancer / 中国肺癌杂志

Phosphorylation is the most common and important post-translational modification of proteins, which plays an important role in the regulation of cell proliferation, differentiation, development and metabolism, and is closely related to the tumorigenesis and metastasis of cancer. Protein kinases and phosphatases generally regulate protein phosphorylation levels as a pair of opposite acting enzymes. Protein phosphorylation in eukaryotes occurs mainly in serine, threonine, and tyrosine residues, and their roles in tumorigenesis and development have been extensively studied. But the roles on histidine phosphorylation is less known due to the immature mass spectrometry and enrichment techniques. In recent years, with the rapid development of related technologies and the discovery of new histidine phosphatases, researchers have paid more attention to the roles of histidine phosphorylation in tumors. Therefore, we aim to review the roles of histidine kinases and phosphatases in tumor.
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Predominant β-lactamase genotypes of Escherichia coli isolates and induction and inhibition mechanisms of β-lactamase gene expression / 中华流行病学杂志

Objective To understand the predominant β-lactamase genotypes and their carrying modes ofEscherichia coli isolates in Zhejiang province,and the effects of β-1actam antibiotics on inducing or histidine kinase inhibitor closantel (CLO) on inhibiting the expression of β-1actamase genes.Methods Micro-dilution method and E-test were applied to measure the resistant rate and minimal inhibitory concentration (MIC) in E.coli isolates against β-1actam antibiotics.PCR and sequence analysis of PCR products were conducted to detect the β-lactamase genotypes and their carrying modes.Real-time fluorescent quantitative RT-PCR and β-lactamase confirmation test were performed to determine the influence of 1/4 MIC penicillin and cefotaxime,and CLO on the transcription and expression of β-lactamase genes in the resistant E.coli isolates.Results Among the 462 E.coli strains isolated in Zhejiang,285 (61.7％) were resistant to penicillin,ampicillin,cefoxitin,cefotaxim and ceftazidime.In the 285 resistant isolates,the detection rate of TEM or CTX-M β-1actamase gene (83.2％ or 75.1％) was significantly higher than that of KPC,SHV or OXA β-lactamase gene (1.4％-10.2％) (P＜0.01) and the carrying rate of two or more β-1actamase genes (68.8％) was also significantly higher than that of single β-1actamase gene (31.2％) (P＜0.01),and 61.4％ of the resistant isolates carried TEM + CTX-M genes (P＜0.01).Except KPC gene,1/4 MIC of cefotaxim and penicillin induced a rapid increase of TEM-mRNA,CTX-M-mRNA,SHV-mRNA or OXA-mRNA levels (P＜0.01),but 50-500 μg/ml CLO inhibited these levels (P＜0.01).After pre-treatment with 100 μg/ml CLO,82.8％-85.6％ of the resistant isolates became sensitive to β-lactam antibiotics (P＜0.01),while the detection rate of β-lactamases was also decreased from 95.1％ to 16.1％ (P＜0.01).Conclusion TEM and CTX-M are the predominant β-lactamase genotypes in E.coli isolates in Zhejiang and TEM+CTX-M is the predominant carrying mode of β-lactamase genes.Low concentrations of β-lactam antibiotics can up-regulate the expression levels of β-lactamase genes in E.coli through bacterial two-component signaling systems,but this effect can be inhibited by CLO,a histidine kinase inhibitor.

The expression of ESBLs genes in Escherichia coli isolates induced by β-lactam antibiotics and inhibited by histidine kinase inhibitors / 中华微生物学和免疫学杂志

Objective To investigate the genotypes of extended spectrum β-lactamases (ESBLs) and their carrying modes in Escherichia coli (E.coli) isolates,and to analyze the mechanism of protein phosphorylation and ESBLs gene expression induced by β-lactam antibiotics or inhibited by histidine kinase inhibitors.Methods The predominant genotypes of ESBLs (KPC,TEM,SHV and CTX-M) and their carrying modes were identified by PCR and sequencing analysis.E-test and micro-tube dilution method were applied to measure minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs).Immobilized metal ion affinity chromatography,bacterial protein phosphorylation detection kit and real-time fluorescent quantitation RT-PCR were performed to analyze the enhancing effects of 1/4 MIC penicillin or cefotaxime or the inhibitory effects of histidine kinase inhibitors (closantel,bromized or iodized methylimidazol) on protein phosphorylation and the expression of ESBLs at mRNA level in E.coli isolates.Results In 183 β-lactam antibiotics-resistant E.coli isolates,TEM and CTX-M genes (83.1％ and 77.1％) were highly expressed than other two ESBLs genes with a prevalent carrying mode of coexisting (65.0％) (P＜0.05).Penicillin or cefotaxime at 1/4 MIC induced the protein phosphorylation and promoted the expression of TEM,SHV and CTX-M at mRNA level (P＜0.05).Closantel (200 μmol),bromized methylimidazol (2 or 10 μmol) or iodized methylimidazol (20 or 50 μmol) could neither kill E.coli isolates nor inhibit their growth,but could inhibit the protein phosphorylation induced by above mentioned antibiotics and enhance the expression of ESBLs at mRNA level (P＜0.05).Moreover,the susceptibility of antibioticresistant E.coli strains to penicillin and cefotaxime were increased (P＜0.05).Conclusion TEM and CTX-M were the predominant genotypes of ESBLs carried by β-lactam antibiotics-resistant E.coli strains isolated from Zhejiang province,which were mostly found in a TEM plus CTX-M carrying mode.Sublethal dose of β-lactam antibiotics could up-regulate the expression of ESBLs genes in E.coli isolates via TCSS,but it could be inhibited by histidine kinase inhibitors.

Structural features of the two-component systemLisR/LisK suggests multiple responses for the adaptation and survival of Listeria monocytogenes

Se caracterizó la estructura del sistema deregulación de dos componentes LisR/LisK de Listeriamonocytogenes. Se emplearon herramientas bioinformáticas ybases de datos para predecir la estructura e interacciones delas dos proteínas y se modelaron. Los resultados predicenque la proteína LisK está embebida en la membrana celulary su composición modular (dominios HAMP, histidinakinasa and ATPasa) está asociada a su autofosforilación(His-266). Un efecto estímulo respuesta determina lapropagación secuencial de la señal desde la membranacelular hacia componentes citoplasmáticos. A su vez, sepredice que LisR es una proteína citosólica con un dominiode receptor (homólogo a cheY) que incluye el residuofosfo-aceptor (Asp-52) y el dominio de unión a ADN,el cual puede permitir la transmisión de una respuestaespecífica a nivel transcripcional. Los componentes LisR/LisK han sido bioquímica y funcionalmente caracterizadosexperimentalmente en la patofisiología de otros bacilos. Espor ello, que la aproximación de los resultados basados enestructura-función podría facilitar el diseño de inhibidoresespecíficos...

Here, we characterized the structure of the two-component regulatory system, LisR/LisK, in Listeriamonocytogenes. To predict the structure of both proteins and the relationship between them, we employedseveral bioinformatic tools and databases. Based on our results, LisK protein is embedded in the cellmembrane and its modular composition (HAMP, histidine kinase and ATPase domains) is associatedwith its autophosphorylation (His-266). A stimulus-response likely determines the sequential signalpropagation from the bacterial cell surface to its cytoplasmic components. According to our results,LisR is a cytoplasmic protein with a receptor domain (homologous to CheY) that comprises a phosphoacceptorresidue (Asp-52) and a DNA-binding domain, which may allow the transmission of a specifictranscriptional response. LisR/LisK has been experimentally characterized both biochemically andfunctionally in other Bacilli pathophysiology; our structure-function approach may facilitate the design ofsuitable inhibitors...

O objetivo do estudo foi caracterizarestruturalmente o sistema de regulação de dois componentesLisR/LisK de Listeria monocytogenes. Foram utilizadasdiversas ferramentas de bioinformática e bancos de dadospara predizer a estrutura das duas proteínas, modelálase prever suas interações. Os resultados predizemque a proteína Lisk está incorporada na composição damembrana celular e sua composição modular (domíniosHAMP, histidina quinase e ATPase) está associada com asua autofosforilação (His-266). Um efeito de estímulo eresposta determina a propagação sequencial do sinal a partirda membrana celular em componentes citoplasmáticos. Osresultados predizem que LisR é uma proteína citosólicacom um domínio recetor (homólogo a CheY) que inclui oresíduo fosfo-aceitador (Asp-52) e o domínio de ligação aoADN, o que pode permitir a transmissão de uma respostaespecífica a nível transcricional. Como LisR/Lisk foi,química e funcionalmente, caracterizada experimentalmentena fisiopatologia de outros bacilos, esta abordagem baseadana estrutura-função pode facilitar a conceção de inibidoresespecíficos...

Cloning and Expression of Histidine Kinase Gene of Aspergillus Fumigatus / 中华皮肤科杂志

Objective Through isolating the histidine kin ase gene of Aspergillus fumigatus,to detect its role in the invasive aspergillosis.Methods Using degenerate primers for highly conserved regions of his-tidine kinase,RT -PCR was performed with cDNA of Aspergillus fumigatus as a template.The gene expression of it in vitro and in vivo was investig ated by Northern blot.Results A fragment of this gene was cloned fro m Aspergillus fumigatus that is highly homologous to tesA gene of Aspergillus nidulans,which was expressed at high level during invasive infection.Conclusion The results indicate that this gene may attribute to the invasive aspergillosis.