Defense against Protein Carbonylation by DnaK/DnaJ and Proteases of the Heat Shock Regulon

Department of Cell and Molecular Biology, Microbiology, Medicinaregatan 9C, 413 90 Göteborg, Sweden.
Journal of Bacteriology (Impact Factor: 2.81). 07/2005; 187(12):4207-13. DOI: 10.1128/JB.187.12.4207-4213.2005
Source: PubMed

ABSTRACT Protein carbonylation is an irreversible oxidative modification that increases during organism aging and bacterial growth arrest. We analyzed whether the heat shock regulon has a role in defending Escherichia coli cells against this deleterious modification upon entry into stationary phase. Providing the cell with ectopically elevated levels of the heat shock transcription factor, sigma32, effectively reduced stasis-induced carbonylation. Separate overproduction of the major chaperone systems, DnaK/DnaJ and GroEL/GroES, established that the former of these is more important in counteracting protein carbonylation. Deletion of the heat shock proteases Lon and HslVU enhanced carbonylation whereas a clpP deletion alone had no effect. However, ClpP appears to have a role in reducing protein carbonyls in cells lacking Lon and HslVU. Proteomic immunodetection of carbonylated proteins in the wild-type, lon, and hslVU strains demonstrated that the same spectrum of proteins displayed a higher load of carbonyl groups in the lon and hslVU mutants. These proteins included the beta-subunit of RNA polymerase, elongation factors Tu and G, the E1 subunit of the pyruvate dehydrogenase complex, isocitrate dehydrogenase, 6-phosphogluconate dehydrogenase, and serine hydroxymethyltranferase.

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    • "Induction of the heat shock operon was analyzed to see whether it could partly counteract the effect of such mistransla - tion and attenuate stasis - induced carbonylation . Chaperones ( Dnak / DnaJ ) and proteases ( Lon and HslVU ) are key factors in the cellular defense against this deleterious oxidative modifica - tion ( Fredriksson et al . , 2005 ) . Proteomic immunodetection of carbonylated proteins in the wild - type , lon , and hslVU strains demonstrated that the same spectrum of proteins displayed a higher load of carbonyl groups in the lon and hslVU mutants . These proteins included the beta - subunit of RNA polymerase , elongation factors Tu and G , the E1 subunit of the p"
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    ABSTRACT: Detection and quantification of protein carbonyls present in biological samples has become a popular, albeit indirect, method to determine the existence of oxidative stress. Moreover, the rise of proteomics has allowed the identification of the specific proteins targeted by protein carbonylation. This review discusses these methodologies and proteomic strategies and then focuses on the relationship between protein carbonylation and aging and the parameters that may explain the increased sensitivity of certain proteins to protein carbonylation. © 2013 Wiley Periodicals, Inc. Mass Spec Rev.
    Mass Spectrometry Reviews 01/2014; 33(1). DOI:10.1002/mas.21375 · 7.71 Impact Factor
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    • "After further analysis, Lon was considered to be part of the heat shock regulon of proteases in bacteria, along with HsIVU, and ClpP. Eventual deletion studies showed that Lon and HsIVU are required in the defense against carbonylation damage, however, deletion of ClpP had no effect and interestingly, Lon can fully compensate for the lack of ClpP [25]. Goldberg and colleagues found that the Protease La, the E. coli homolog for Lon, can degrade small hydrophobic peptides [26]. "
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    ABSTRACT: The elimination of oxidatively modified proteins is a crucial process in maintaining cellular homeostasis, especially during stress. Mitochondria are protein-dense, high traffic compartments, whose polypeptides are constantly exposed to superoxide, hydrogen peroxide, and other reactive species, generated by 'electron leakage' from the respiratory chain. The level of oxidative stress to mitochondrial proteins is not constant, but instead varies greatly with numerous metabolic and environmental factors. Oxidized mitochondrial proteins must be removed rapidly (by proteolytic degradation) or they will aggregate, cross-link, and cause toxicity. The Lon Protease is a key enzyme in the degradation of oxidized proteins within the mitochondrial matrix. Under conditions of acute stress Lon is highly inducible, possibly with the oxidant acting as the signal inducer, thereby providing increased protection. It seems that under chronic stress conditions, however, Lon levels actually decline. Lon levels also decline with age and with senescence, and senescent cells even lose the ability to induce Lon during acute stress. We propose that the regulation of Lon is biphasic, in that it is up-regulated during transient stress and down-regulated during chronic stress and aging, and we suggest that the loss of Lon responsiveness may be a significant factor in aging, and in age-related diseases.
    02/2013; 1(1):258-264. DOI:10.1016/j.redox.2013.01.015
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    • "The aerobic metabolism generates reactive oxygen species (ROS) [96] that can damage DNA, lipids, and proteins [97]. In order to cope with oxygen toxicity and grow in aerobic conditions, Bacteria expressed genes correlated to oxidative stress, such as Superoxide dismutase, Glutaredoxins and Alkyl hydroperoxide reductase [98], and also stress related chaperones such as GroEL, DnaJ and DnaK [99,100]. "
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    ABSTRACT: Background Seaweeds of the Laurencia genus have a broad geographic distribution and are largely recognized as important sources of secondary metabolites, mainly halogenated compounds exhibiting diverse potential pharmacological activities and relevant ecological role as anti-epibiosis. Host-microbe interaction is a driving force for co-evolution in the marine environment, but molecular studies of seaweed-associated microbial communities are still rare. Despite the large amount of research describing the chemical compositions of Laurencia species, the genetic knowledge regarding this genus is currently restricted to taxonomic markers and general genome features. In this work we analyze the transcriptomic profile of L. dendroidea J. Agardh, unveil the genes involved on the biosynthesis of terpenoid compounds in this seaweed and explore the interactions between this host and its associated microbiome. Results A total of 6 transcriptomes were obtained from specimens of L. dendroidea sampled in three different coastal locations of the Rio de Janeiro state. Functional annotations revealed predominantly basic cellular metabolic pathways. Bacteria was the dominant active group in the microbiome of L. dendroidea, standing out nitrogen fixing Cyanobacteria and aerobic heterotrophic Proteobacteria. The analysis of the relative contribution of each domain highlighted bacterial features related to glycolysis, lipid and polysaccharide breakdown, and also recognition of seaweed surface and establishment of biofilm. Eukaryotic transcripts, on the other hand, were associated with photosynthesis, synthesis of carbohydrate reserves, and defense mechanisms, including the biosynthesis of terpenoids through the mevalonate-independent pathway. Conclusions This work describes the first transcriptomic profile of the red seaweed L. dendroidea, increasing the knowledge about ESTs from the Florideophyceae algal class. Our data suggest an important role for L. dendroidea in the primary production of the holobiont and the role of Bacteria as consumers of organic matter and possibly also as nitrogen source. Furthermore, this seaweed expressed sequences related to terpene biosynthesis, including the complete mevalonate-independent pathway, which offers new possibilities for biotechnological applications using secondary metabolites from L. dendroidea.
    BMC Genomics 09/2012; 13(1):487. DOI:10.1186/1471-2164-13-487 · 3.99 Impact Factor
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