Read by QxMD icon Read


Joanna Krysiak, Matthias Stahl, Jan Vomacka, Christian Fetzer, Markus Lakemeyer, Anja Fux, Stephan A Sieber
β-Lactones have recently been introduced as the first selective ClpP inhibitors that attenuate virulence of both sensitive Staphylococcus aureus and multiresistant strains (MRSA). Although previous knockout studies showed that ClpP is essential for S. aureus alpha-toxin production, a link between β-lactone inhibition and molecular virulence mechanisms has been lacking so far. We here perform a chemical-proteomic approach to elucidate antivirulence pathways. First, we demonstrate by gel-free activity-based protein profiling that ClpP is the predominant target of β-lactones...
February 10, 2017: Journal of Proteome Research
Marissa G Viola, Christopher J LaBreck, Joseph Conti, Jodi L Camberg
During bacterial cell division a dynamic protein structure called the Z-ring assembles at the septum. The major protein in the Z-ring in Escherichia coli is FtsZ, a tubulin homolog that polymerizes with GTP. FtsZ is degraded by the two-component ATP-dependent protease ClpXP. Two regions of FtsZ, located outside of the polymerization domain in the unstructured linker and at the C-terminus, are important for specific recognition and degradation by ClpXP. We engineered a synthetic substrate containing green fluorescent protein (Gfp) fused to an extended FtsZ C-terminal tail (residues 317-383), including the unstructured linker and the C-terminal conserved region, but not the polymerization domain, and showed that it is sufficient to target a non-native substrate for degradation in vitro...
2017: PloS One
Eiji Kinoshita, Emiko Kinoshita-Kikuta, Kiyonobu Karata, Toshiki Kawano, Atsuhiro Nishiyama, Morihisa Yamato, Tohru Koike
We describe two unique proteins, Escherichia coli ClpX and human histone H2A, that show extremely retarded migrations relative to their molecular weights in Phos-tag SDS-PAGE, despite being nonphosphorylated. Although ClpX separated into multiple migration bands in Phos-tag gels, the separation was not due to phosphorylation. The N-terminal 47-61 region of ClpX was responsible for producing multiple phosphorylation-independent structural variants, even under denaturing conditions, and some of these variants were detected as highly up-shifted bands...
January 23, 2017: Electrophoresis
Van Chi Thai, Teck Kwang Lim, Kim Phuong Uyen Le, Qingsong Lin, Thi Thu Hoai Nguyen
OBJECTIVES: The aim of this study was to compare global protein expression changes during fluoroquinolone (FQ) exposure of Staphylococcus aureus. METHODS: Total protein extracts of wild-type S. aureus ATCC 29213 and six multidrug-resistant (MDR) strains derived from the wild-type under different FQ exposures were analysed using the 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) method combined with LC-MS/MS analysis. Differentially expressed proteins were searched for their Gene Ontology (GO) annotation (UniProt database) and protein-protein interaction network (STRING v...
December 27, 2016: Journal of Global Antimicrobial Resistance
Biswanath Jana, Liang Tao, Indranil Biswas
Streptococcus mutans, a dental pathogen, has a remarkable ability to cope with environmental stresses. Under stress conditions, cytoplasmic proteases play a major role in controlling the stability of regulatory proteins and preventing accumulation of damaged and misfolded proteins. ClpXP, a well-conserved cytoplasmic proteolytic system, is crucial in maintaining cellular homeostasis in bacteria. ClpX is primarily responsible for recognition of substrates and subsequent translocation of unfolded substrates into the ClpP proteolytic compartment for degradation...
November 2016: MSphere
H Li, H Ji, S S Wu, B X Hou
Objective: To analyze the protein expression profile and the potential virulence factors of Porphyromonas endodontalis (Pe) via comparison with that of two strains of Porphyromonas gingivalis (Pg) with high and low virulences, respectively. Methods: Whole cell comparative proteomics of Pe ATCC35406 was examined and compared with that of high virulent strain Pg W83 andlow virulent strain Pg ATCC33277, respectively. Isobaric tags for relative and absolute quantitation (iTRAQ) combined with nano liquid chromatography-tandem mass spectrometry (Nano-LC-MS/MS) were adopted to identify and quantitate the proteins of Pe and two strains of Pg with various virulences by using the methods of isotopically labeled peptides, mass spectrometric detection and bioinformatics analysis...
December 9, 2016: Zhonghua Kou Qiang Yi Xue za Zhi, Zhonghua Kouqiang Yixue Zazhi, Chinese Journal of Stomatology
Branwen M Hall, Elena B M Breidenstein, César de la Fuente-Núñez, Fany Reffuveille, Gina D Mawla, Robert E W Hancock, Tania A Baker
Caseinolytic peptidases (ClpPs) regulate diverse aspects of cellular physiology in bacteria. Some species have multiple ClpPs including opportunistic pathogen Pseudomonas aeruginosa in which there is an archetypical isoform, ClpP1, and a second isoform, ClpP2, about which little is known. Here we use phenotypic assays to investigate biological roles of ClpP1 and ClpP2 and biochemical assays to characterize purified ClpP1, ClpP2, ClpX and ClpA. Interestingly ClpP1 and ClpP2 have distinct intracellular roles for motility, pigment production, iron scavenging and biofilm formation...
November 14, 2016: Journal of Bacteriology
Piere Rodriguez-Aliaga, Luis Ramirez, Frank Kim, Carlos Bustamante, Andreas Martin
ATP-dependent proteases of the AAA+ family, including Escherichia coli ClpXP and the eukaryotic proteasome, contribute to maintenance of cellular proteostasis. ClpXP unfolds and translocates substrates into an internal degradation chamber, using cycles of alternating dwell and burst phases. The ClpX motor performs chemical transformations during the dwell and translocates the substrate in increments of 1-4 nm during the burst, but the processes occurring during these phases remain unknown. Here we characterized the complete mechanochemical cycle of ClpXP, showing that ADP release and ATP binding occur nonsequentially during the dwell, whereas ATP hydrolysis and phosphate release occur during the burst...
November 2016: Nature Structural & Molecular Biology
Bobbi S Pritt, Laurel B Respicio-Kingry, Lynne M Sloan, Martin E Schriefer, Adam J Replogle, Jenna Bjork, Gongping Liu, Luke C Kingry, Paul S Mead, David F Neitzel, Elizabeth Schiffman, Diep K Hoang Johnson, Jeffrey P Davis, Susan M Paskewitz, David Boxrud, Alecia Deedon, Xia Lee, Tracy K Miller, Michelle A Feist, Christopher R Steward, Elitza S Theel, Robin Patel, Cole L Irish, Jeannine M Petersen
Lyme borreliosis (LB) is a multisystem disease caused by spirochetes in the Borrelia burgdorferisensu lato (Bbsl) genospecies complex. We previously described a novel Bbsl genospecies (type strain MN14-1420T) that causes LB among patients with exposures to ticks in the upper midwestern USA. Patients infected with the novel Bbsl genospecies demonstrated higher levels of spirochetemia and somewhat differing clinical symptoms as compared with those infected with other Bbsl genospecies. The organism was detected from human specimens using PCR, microscopy, serology and culture...
November 2016: International Journal of Systematic and Evolutionary Microbiology
Kristoffer T Bæk, Lisa Bowman, Charlotte Millership, Mia Dupont Søgaard, Volkhard Kaever, Pia Siljamäki, Kirsi Savijoki, Pekka Varmanen, Tuula A Nyman, Angelika Gründling, Dorte Frees
UNLABELLED: Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase) gene arise spontaneously in an S. aureus mutant lacking the ClpX chaperone. A wide variety of ltaS mutations were selected, and among these, a substantial portion resulted in premature stop codons and other changes predicted to abolish LtaS synthesis...
2016: MBio
Yoshiko Kubota, Kazumi Nomura, Yasutake Katoh, Rina Yamashita, Kiriko Kaneko, Kazumichi Furuyama
In eukaryotic cells, heme production is tightly controlled by heme itself through negative feedback-mediated regulation of nonspecific 5-aminolevulinate synthase (ALAS1), which is a rate-limiting enzyme for heme biosynthesis. However, the mechanism driving the heme-dependent degradation of the ALAS1 protein in mitochondria is largely unknown. In the current study, we provide evidence that the mitochondrial ATP-dependent protease ClpXP, which is a heteromultimer of CLPX and CLPP, is involved in the heme-dependent degradation of ALAS1 in mitochondria...
September 23, 2016: Journal of Biological Chemistry
Jae Ho Seo, Dayana B Rivadeneira, M Cecilia Caino, Young Chan Chae, David W Speicher, Hsin-Yao Tang, Valentina Vaira, Silvano Bosari, Alessandro Palleschi, Paolo Rampini, Andrew V Kossenkov, Lucia R Languino, Dario C Altieri
Mitochondria must buffer the risk of proteotoxic stress to preserve bioenergetics, but the role of these mechanisms in disease is poorly understood. Using a proteomics screen, we now show that the mitochondrial unfoldase-peptidase complex ClpXP associates with the oncoprotein survivin and the respiratory chain Complex II subunit succinate dehydrogenase B (SDHB) in mitochondria of tumor cells. Knockdown of ClpXP subunits ClpP or ClpX induces the accumulation of misfolded SDHB, impairing oxidative phosphorylation and ATP production while activating "stress" signals of 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and autophagy...
July 2016: PLoS Biology
A Trmčić, K Chauhan, D J Kent, R D Ralyea, N H Martin, K J Boor, M Wiedmann
Coliform detection in finished products, including cheese, has traditionally been used to indicate whether a given product has been manufactured under unsanitary conditions. As our understanding of the diversity of coliforms has improved, it is necessary to assess whether coliforms are a good indicator organism and whether coliform detection in cheese is associated with the presence of pathogens. The objective of this study was (1) to evaluate cheese available on the market for presence of coliforms and key pathogens, and (2) to characterize the coliforms present to assess their likely sources and public health relevance...
August 2016: Journal of Dairy Science
M A Veselova, Yu M Romanova, V A Lipasova, O A Koksharova, Yu V Zaitseva, M U Chernukha, A L Gintsburg, I A Khmel
In order to study the regulation of N-acyl-homoserine lactones synthesis (AHLs, the signal molecules of Quorum Sensing regulation) in Burkholderia cenocepacia strain 370 we obtained mutants with increased AHL production. One of the mutants, named BC-B6, was obtained by TnMod-RKm(r) plasposon mutagenesis. The plasposon insertion was located within the clpX gene encoding the ATPase subunit ClpX of the ClpXP protease. The mutation reduced bacterial virulence in mice intranasal infection. The results of proteomic analysis demonstrated that the expression of at least 19 proteins differed not less than 2-fold between the parental and mutant strains...
May 2016: Microbiological Research
Qiuhua Bao, Yuqin Song, Haiyan Xu, Jie Yu, Wenyi Zhang, Bilige Menghe, Heping Zhang, Zhihong Sun
Lactobacillus casei is a lactic acid bacterium used in manufacturing of many fermented food products. To investigate the genetic diversity and population biology of this food-related bacterium, 224 Lb. casei isolates and 5 reference isolates were examined by multilocus sequence typing (MLST). Among them, 224 Lb. casei isolates were isolated from homemade fermented foods, including naturally fermented dairy products, acidic gruel, and Sichuan pickles from 38 different regions in China and Mongolia. The MLST scheme was developed based on the analysis of 10 selected housekeeping genes (carB, clpX, dnaA, groEL, murE, pyrG, pheS, recA, rpoC, and uvrC)...
July 2016: Journal of Dairy Science
Korrie L Mack, James Shorter
Cells have evolved a sophisticated proteostasis network to ensure that proteins acquire and retain their native structure and function. Critical components of this network include molecular chaperones and protein disaggregases, which function to prevent and reverse deleterious protein misfolding. Nevertheless, proteostasis networks have limits, which when exceeded can have fatal consequences as in various neurodegenerative disorders, including Parkinson's disease and amyotrophic lateral sclerosis. A promising strategy is to engineer proteostasis networks to counter challenges presented by specific diseases or specific proteins...
2016: Frontiers in Molecular Biosciences
Alvaro J Amor, Karl R Schmitz, Jason K Sello, Tania A Baker, Robert T Sauer
The ClpXP protease assembles in a reaction in which an ATP-bound ring hexamer of ClpX binds to one or both heptameric rings of the ClpP peptidase. Contacts between ClpX IGF-loops and clefts on a ClpP ring stabilize the complex. How ClpXP stability is maintained during the ATP-hydrolysis cycle that powers mechanical unfolding and translocation of protein substrates is poorly understood. Here, we use a real-time kinetic assay to monitor the effects of nucleotides on the assembly and disassembly of ClpXP. When ATP is present, complexes containing single-chain ClpX assemble via an intermediate and remain intact until transferred into buffers containing ADP or no nucleotides...
June 17, 2016: ACS Chemical Biology
Monika S Buczek, Andrea L Cardenas Arevalo, Anuradha Janakiraman
The bacterial FtsZ-ring is an essential cytokinetic structure under tight spatiotemporal regulation. In Escherichia coli, FtsZ polymerization and assembly into the Z-ring is controlled on multiple levels through interactions with positive and negative regulators. Among these regulatory factors are ZapC, a Z-ring stabilizer, and the conserved protease ClpXP, which has been shown to degrade FtsZ protofilaments in preference to FtsZ monomers. Here we report that ZapC and ClpX interact in a protein-protein interaction assay, and that ZapC is degraded in a ClpXP-dependent manner in vivo...
June 2016: Microbiology
Yu-Tzu Lin, Jui-Chang Tsai, Tatsuo Yamamoto, Hsiao-Jan Chen, Wei-Chun Hung, Po-Ren Hsueh, Lee-Jene Teng
OBJECTIVES: Small colony variants (SCVs) of Staphylococcus aureus are associated with persistent and drug-resistant infections. We demonstrated for the first time the emergence of SCVs in a patient with vancomycin-intermediate S. aureus (VISA) infection during long-term treatment with daptomycin. METHODS: A 73-year-old man with septic arthritis was infected with VISA. The patient was treated with daptomycin; however, the patient remained infected with VISA, with continuous isolation of VISA from his blood during long-term treatment...
July 2016: Journal of Antimicrobial Chemotherapy
Kirsten Famulla, Peter Sass, Imran Malik, Tatos Akopian, Olga Kandror, Marina Alber, Berthold Hinzen, Helga Ruebsamen-Schaeff, Rainer Kalscheuer, Alfred L Goldberg, Heike Brötz-Oesterhelt
The Clp protease complex in Mycobacterium tuberculosis is unusual in its composition, functional importance and activation mechanism. Whilst most bacterial species contain a single ClpP protein that is dispensable for normal growth, mycobacteria have two ClpPs, ClpP1 and ClpP2, which are essential for viability and together form the ClpP1P2 tetradecamer. Acyldepsipeptide antibiotics of the ADEP class inhibit the growth of Gram-positive firmicutes by activating ClpP and causing unregulated protein degradation...
July 2016: Molecular Microbiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"