scholarly journals Role of Escherichia coli heat shock proteins IbpA and IbpB in protection of alcohol dehydrogenase AdhE against heat inactivation in the presence of oxygen.

2009 ◽  
Vol 56 (1) ◽  
Author(s):  
Ewelina Matuszewska ◽  
Joanna Kwiatkowska ◽  
Elzbieta Ratajczak ◽  
Dorota Kuczyńska-Wiśnik ◽  
Ewa Laskowska
Keyword(s):  
Escherichia Coli ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Alcohol Dehydrogenase ◽  
Heat Inactivation ◽  
Prolonged Incubation ◽  
Oxidative Inactivation ◽  
Shock Proteins

Escherichia coli small heat shock proteins IbpA and IbpB are molecular chaperones that bind denatured proteins and facilitate their subsequent refolding by the ATP-dependent chaperones DnaK/DnaJ/GrpE and ClpB. In vivo, the lack of IbpA and IbpB proteins results in increased protein aggregation under severe heat stress or delayed removal of aggregated proteins at recovery temperatures. In this report we followed the appearance and removal of aggregated alcohol dehydrogenase, AdhE, in E. coli submitted to heat stress in the presence of oxygen. During prolonged incubation of cells at 50 degrees C, when AdhE was progressively inactivated, we initially observed aggregation of AdhE and thereafter removal of aggregated AdhE. In contrast to previous studies, the lack of IbpA and IbpB did not influence the formation and removal of AdhE aggregates. However, in DeltaibpAB cells AdhE was inactivated and oxidized faster than in wild type strain. Our results demonstrate that IbpA and IbpB protected AdhE against thermal and oxidative inactivation, providing that the enzyme remained soluble. IbpA and IbpB were dispensable for the processing of irreversibly damaged and aggregated AdhE.

In vivo evidence from an Agrostis stolonifera selection genotype that chloroplast small heat-shock proteins can protect photosystem II during heat stress

2002 ◽  
Vol 29 (8) ◽  
pp. 935 ◽  
Author(s):  
Scott A. Heckathorn ◽  
Samantha L. Ryan ◽  
Joanne A. Baylis ◽  
Dongfang Wang ◽  
E. William Hamilton III ◽  
...  
Keyword(s):  
Heat Stress ◽  
Electron Transport ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Agrostis Stolonifera ◽  
Small Heat Shock Proteins ◽  
O2 Evolution ◽  
Shock Proteins ◽  
Tolerant Genotype

Previous in vitro experiments indicated that chloroplast small heat-shock proteins (sHsp) could associate with thylakoids and protect PSII during heat and other stresses, possibly by stabilizing the O2-evolving complex (OEC). However, in vivo evidence of sHsp protection of PSII is equivocal at present. Using previously characterized selection genotypes of Agrostis stolonifera Huds. that differ in thermotolerance and production of chloroplast sHsps, we show that both genotypes contain thylakoid-associating sHsps, but the heat-tolerant genotype, which produces an additional sHsp isoform not made by the sensitive genotype, produces a greater quantity of chloroplast and thylakoid sHsp. Following a pre-heat stress to induce sHsps, in vivo PSII function decreased less at high temperatures in the tolerant genotype. Differences in PSII thermotolerance in vivo were associated with increased thermotolerance of the OEC proteins and O2-evolving function of PSII, and not with other PSII proteins or functions examined. In vivo cross-linking experiments indicated that a greater amount of sHsp associated with PSII proteins during heat stress in the tolerant genotype. PSII was the most thermosensitive component of photosynthetic electron transport, and no differences between genotypes in the thermotolerance of other electron transport components were observed. These results indicate that in vivo chloroplast sHsps can protect O2 evolution and the OEC proteins of PSII during heat stress.

scholarly journals The Escherichia coli small heat-shock proteins IbpA and IbpB prevent the aggregation of endogenous proteins denatured in vivo during extreme heat shock

Microbiology ◽  
2002 ◽  
Vol 148 (6) ◽  
pp. 1757-1765 ◽  
Author(s):  
Dorota Kuczynska-Wisnik ◽  
Sabina Kçdzierska ◽  
Ewelina Matuszewska ◽  
Peter Lund ◽  
Alina Taylor ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
Extreme Heat ◽  
Endogenous Proteins ◽  
Shock Proteins

scholarly journals Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro.

1989 ◽  
Vol 171 (3) ◽  
pp. 1590-1596 ◽  
Author(s):  
C Johnson ◽  
G N Chandrasekhar ◽  
C Georgopoulos
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Shock Proteins

scholarly journals Escherichia coli small heat shock protein IbpA is an aggregation-sensor that self-regulates its own expression at a translational level

2020 ◽  
Author(s):  
Tsukumi Miwa ◽  
Yuhei Chadani ◽  
Hideki Taguchi
Keyword(s):  
Escherichia Coli ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Protein Aggregation ◽  
Protein Aggregates ◽  
Negative Feedback Regulation ◽  
Denatured Proteins ◽  
Shock Proteins ◽  
Translational Level

AbstractAggregation is an inherent characteristic of proteins. Risk management strategies to reduce aggregation are critical for cells to survive upon stresses that induce aggregation. Cells cope with protein aggregation by utilizing a variety of chaperones, as exemplified by heat-shock proteins (Hsps). The heat stress-induced expression of IbpA and IbpB, small Hsps in Escherichia coli, is regulated by the σ32 heat-shock transcriptional regulator and the temperature-dependent translational regulation via mRNA heat fluctuation. We found that, even without heat stress, either the expression of aggregation-prone proteins or the ibpA gene deletion profoundly increases the expression of IbpA. Combined with other evidence, we propose novel mechanisms for the regulation of the small Hsp expression. Oligomeric IbpA self-represses the ibpA/ibpB expression at the translational level, but the self-repression is relieved by the sequestration of IbpA into protein aggregates. Thus, the function of IbpA as a chaperone to form co-aggregates is harnessed as an aggregation sensor to tightly regulate the IbpA level. Since the excessive preemptive supply of IbpA in advance of stress is harmful, the prodigious and rapid expression of IbpA/IbpB on demand is necessary for IbpA to function as a first line of defense against acute protein aggregation.Author summaryAll organisms have protein quality control systems against stresses disturbing cellular protein homeostasis (proteostasis). The systems have multiple stages: folding, degradation, and sequestration. Sequestration of denatured proteins is the first step to support other maintenance strategies. Small heat shock proteins (sHsps), which are well-conserved chaperones, are representative “sequestrases” that co-aggregate with denatured proteins. We found that IbpA, an Escherichia coli sHsp, is a direct mediator for negative feedback regulation at the translational level. Recruitment of IbpA into the protein aggregates relieves the ibpA expression suppression. This novel mechanism of IbpA as an aggregation-sensor tightly regulates the IbpA level, enabling the sHsp to function as a sequestrase upon aggregation stress.

scholarly journals Roles of the Escherichia coli Small Heat Shock Proteins IbpA and IbpB in Thermal Stress Management: Comparison with ClpA, ClpB, and HtpG In Vivo

1998 ◽  
Vol 180 (19) ◽  
pp. 5165-5172 ◽  
Author(s):  
Jeffrey G. Thomas ◽  
François Baneyx
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
High Temperatures ◽  
Small Heat Shock Proteins ◽  
Host Protein ◽  
E Coli ◽  
Growth Defects ◽  
Shock Proteins

ABSTRACT We have constructed an Escherichia coli strain lacking the small heat shock proteins IbpA and IbpB and compared its growth and viability at high temperatures to those of isogenic cells containing null mutations in the clpA, clpB, orhtpG gene. All mutants exhibited growth defects at 46°C, but not at lower temperatures. However, the clpA,htpG, and ibp null mutations did not reduce cell viability at 50°C. When cultures were allowed to recover from transient exposure to 50°C, all mutations except Δibpled to suboptimal growth as the recovery temperature was raised. Deletion of the heat shock genes clpB and htpGresulted in growth defects at 42°C when combined with thednaK756 or groES30 alleles, while the Δibp mutation had a detrimental effect only on the growth of dnaK756 mutants. Neither the overexpression of these heat shock proteins nor that of ClpA could restore the growth ofdnaK756 or groES30 cells at high temperatures. Whereas increased levels of host protein aggregation were observed indnaK756 and groES30 mutants at 46°C compared to wild-type cells, none of the null mutations had a similar effect. These results show that the highly conserved E. coli small heat shock proteins are dispensable and that their deletion results in only modest effects on growth and viability at high temperatures. Our data also suggest that ClpB, HtpG, and IbpA and -B cooperate with the major E. coli chaperone systems in vivo.

scholarly journals Proteomic analysis of heat shock proteins in maize (Zea mays L.)

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Mahmoud Hussien Abou-Deif ◽  
Mohamed Abdel-Salam Rashed ◽  
Kamal Mohamed Khalil ◽  
Fatma El-Sayed Mahmoud
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Proteome Analysis ◽  
High Temperature Stress ◽  
Heat Treatments ◽  
Maize Plants ◽  
Adverse Influence ◽  
Shock Proteins

Abstract Background Maize is one of the important cereal food crops in the world. High temperature stress causes adverse influence on plant growth. When plants are exposed to high temperatures, they produce heat shock proteins (HSPs), which may impart a generalized role in tolerance to heat stress. Proteome analysis was performed in plant to assess the changes in protein types and their expression levels under abiotic stress. The purpose of the study is to explore which proteins are involved in the response of the maize plant to heat shock treatment. Results We investigated the responses of abundant proteins of maize leaves, in an Egyptian inbred line of maize “K1”, upon heat stress through two-dimensional electrophoresis (2-DE) on samples of maize leaf proteome. 2-DE technique was used to recognize heat-responsive protein spots using Coomassie Brilliant Blue (CBB) and silver staining. In 2-D analysis of proteins from plants treated at 45 °C for 2 h, the results manifested 59 protein spots (4.3%) which were reproducibly detected as new spots where did not present in the control. In 2D for treated plants for 4 h, 104 protein spots (7.7%) were expressed only under heat stress. Quantification of spot intensities derived from heat treatment showed that twenty protein spots revealed clear differences between the control and the two heat treatments. Nine spots appeared with more intensity after heat treatments than the control, while four spots appeared only after heat treatments. Five spots were clearly induced after heat treatment either at 2 h or 4 h and were chosen for more analysis by LC-MSMS. They were identified as ATPase beta subunit, HSP26, HSP16.9, and unknown HSP/Chaperonin. Conclusion The results revealed that the expressive level of the four heat shock proteins that were detected in this study plays important roles to avoid heat stress in maize plants.

Principles of chaperone-mediated protein folding

1995 ◽  
Vol 348 (1323) ◽  
pp. 107-112 ◽  
Keyword(s):  
Protein Folding ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Molecular Chaperones ◽  
Cellular Protein ◽  
Chaperone Proteins ◽  
Shock Proteins ◽  
Polypeptide Chains

The recent discovery of molecular chaperones and their functions has changed dramatically our view of the processes underlying the folding of proteins in vivo . Rather than folding spontaneously, most newly synthesized polypeptide chains seem to acquire their native conformations in a reaction mediated by chaperone proteins. Different classes of molecular chaperones, such as the members of the Hsp70 and Hsp60 families of heat-shock proteins, cooperate in a coordinated pathway of cellular protein folding.

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