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 Immunomodulation of function of small heat shock proteins prevents their assembly into heat stress granules and results in cell death at sublethal temperatures

2004 ◽  
Vol 41 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Sergey Miroshnichenko ◽  
Joanna Tripp ◽  
Uta zur Nieden ◽  
Dieter Neumann ◽  
Udo Conrad ◽  
...  
Keyword(s):  
Cell Death ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Stress Granules ◽  
Small Heat Shock Proteins ◽  
Shock Proteins

Cellular Functions and Mechanisms of Action of Small Heat Shock Proteins

2019 ◽  
Vol 73 (1) ◽  
pp. 89-110 ◽  
Author(s):  
Axel Mogk ◽  
Carmen Ruger-Herreros ◽  
Bernd Bukau
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Protein Unfolding ◽  
Small Heat Shock Proteins ◽  
Cellular Functions ◽  
Independent Manner ◽  
Cellular Defense ◽  
Shock Proteins ◽  
Substrate Binding Sites

Small heat shock proteins (sHsps) constitute a diverse chaperone family that shares the α-crystallin domain, which is flanked by variable, disordered N- and C-terminal extensions. sHsps act as the first line of cellular defense against protein unfolding stress. They form dynamic, large oligomers that represent inactive storage forms. Stress conditions cause a rapid increase in cellular sHsp levels and trigger conformational rearrangements, resulting in exposure of substrate-binding sites and sHsp activation. sHsps bind to early-unfolding intermediates of misfolding proteins in an ATP-independent manner and sequester them in sHsp/substrate complexes. Sequestration protects substrates from further uncontrolled aggregation and facilitates their refolding by ATP-dependent Hsp70-Hsp100 disaggregases. Some sHsps with particularly strong sequestrase activity, such as yeast Hsp42, are critical factors for forming large, microscopically visible deposition sites of misfolded proteins in vivo. These sites are organizing centers for triaging substrates to distinct quality control pathways, preferentially Hsp70-dependent refolding and selective autophagy.

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.

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 Mitochondrial Small Heat Shock Proteins Are Essential for Normal Growth of Arabidopsis thaliana

2021 ◽  
Vol 12 ◽  
Author(s):  
Mariela R. Escobar ◽  
Ivo Feussner ◽  
Estela M. Valle
Keyword(s):  
Arabidopsis Thaliana ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Plant Growth ◽  
Stress Responses ◽  
Small Heat Shock Proteins ◽  
Healthy Plant ◽  
Knock Down ◽  
Shock Proteins

Mitochondria play important roles in the plant stress responses and the detoxification of the reactive oxygen species generated in the electron transport chain. Expression of genes encoding stress-related proteins such as the mitochondrial small heat shock proteins (M-sHSP) is upregulated in response to different abiotic stresses. In Arabidopsis thaliana, three M-sHSPs paralogous genes were identified, although their function under physiological conditions remains elusive. The aim of this work is to uncover the in vivo function of all three M-sHSPs at the whole plant level. To accomplish this goal, we analyzed the phenotype, proteomic, and metabolic profiles of Arabidopsis knock-down lines of M-sHSPs (single, double, and triple knock-down lines) during normal plant growth. The triple knock-down plants showed the most prominent altered phenotype at vegetative and reproductive stages without any externally applied stress. They displayed chlorotic leaves, growth arrest, and low seed production. Concomitantly, they exhibited increased levels of sugars, proline, and citric, malic, and ascorbic acid, among other metabolites. In contrast, single and double knock-down plants displayed a few changes in their phenotype. A redundant function among the three M-sHSPs is indicated by the impairment in vegetative and reproductive growth associated with the simultaneous loss of all three M-sHSPs genes. The triple knock-down lines showed alteration of proteins mainly involved in photosynthesis and antioxidant defense compared to the control plants. On the other hand, heat stress triggered a distinct cytosolic response pattern and the upregulation of other sHSP members, in the knock-down plants. Overall, depletion of all three M-sHSPs in Arabidopsis severely impacted fundamental metabolic processes, leading to alterations in the correct plant growth and development. These findings expand our knowledge about the contribution of organelle-specific M-sHSPs to healthy plant growth under non-stress conditions.

scholarly journals Small Heat Shock Proteins Protect Electron Transport in Chloroplasts and Mitochondria During Stress

1999 ◽  
Vol 39 (6) ◽  
pp. 865-876 ◽  
Author(s):  
SCOTT A. HECKATHORN ◽  
CRAIG A. DOWNS ◽  
JAMES S. COLEMAN
Keyword(s):  
Electron Transport ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
Shock Proteins

scholarly journals Developmental and heat stress-regulated expression of HsfA2 and small heat shock proteins in tomato anthers

2009 ◽  
Vol 61 (2) ◽  
pp. 453-462 ◽  
Author(s):  
Filomena Giorno ◽  
Mieke Wolters-Arts ◽  
Stefania Grillo ◽  
Klaus-Dieter Scharf ◽  
Wim H. Vriezen ◽  
...  
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
Regulated Expression ◽  
Shock Proteins
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