The mitochondrial small heat‐shock protein protects NADH:ubiquinone oxidoreductase of the electron transport chain during heat stress in plants

Rhoads

Journal of Biological Chemistry

et al. 2001

A maize (Zea mays L.) small heat shock protein (HSP), HSP22, was previously shown to accumulate to high levels in mitochondria during heat stress. Here we have purified native HSP22 and resolved the protein into three peaks using reverse phase high performance liquid chromatography. Mass spectrometry (MS) of the first two peaks revealed the presence of two HSP22 forms in each peak which differed in mass by 80 daltons (Da), indicative of a monophosphorylation. Phosphorylation of HSP22 by [␥-32 P]ATP was also observed in mitochondria labeled in vitro, but not when purified native HSP22 was similarly used, demonstrating that HSP22 does not autophosphorylate, implicating a kinase involvement in vivo. Collisionally induced dissociation tandem MS (CID MS/MS) identified Ser59 as the phosphorylated residue. We have also observed forms of HSP22 that result from alternative intron splicing. The two HSP22 proteins in the first peak were ϳ57 Da larger than the two HSP22 proteins in the second peak. MS analysis revealed that the ؉57-Da forms have an additional Gly residue directly N-terminal of the expected Asp 84 , which had been converted to an Asn residue. These results are the first demonstrations of phosphorylation and alternative intron splicing of a plant small HSP.

Section: Discussionmentioning

confidence: 99%

“…The cytosolic forms of plant sHSPs have been shown to have chaperone function (18), and, recently, evidence that mitochondrial sHSPs function as chaperones has been provided by experiments of Downs and Heckathorn (19). They have shown in a number of different ways that mitochondrial HSP22 protects complex I activity during heat stress.…”

mentioning

confidence: 99%

In Vivo Modifications of the Maize Mitochondrial Small Heat Stress Protein, HSP22

Rhoads

Journal of Biological Chemistry

et al. 2001

“…Studies on heat-stress response in plant mitochondria have been mainly focused on characterization of heat shock proteins (HSPs) (Neumann et al, 1993;Lund et al, 1998). Only one mitochondrial small heat shock protein, which provides thermotolerance to respiratory complex I (Downs and Heckathorn, 1998), has been functionally studied. Investigations of the possible involvement of other proteins such as NDPK in mitochondrial response to heat stress are therefore relevant.…”

mentioning

confidence: 99%

Heat Stress Response in Pea Involves Interaction of Mitochondrial Nucleoside Diphosphate Kinase with a Novel 86-Kilodalton Protein

et al. 2001

In this work we have further characterized the first mitochondrial nucleoside diphosphate kinase (mtNDPK) isolated from plants. The mitochondrial isoform was found to be especially abundant in reproductive and young tissues. Expression of the pea (Pisum sativum L. cv Oregon sugarpod) mtNDPK was not affected by different stress conditions. However, the pea mtNDPK was found to interact with a novel 86-kD protein, which is de novo synthesized in pea leaves upon exposure to heat. Thus, we have evidence for the involvement of mtNDPK in mitochondrial heat response in pea in vivo. Studies on oligomerization revealed that mtNDPK was found in complexes of various sizes, corresponding to the sizes of e.g. hexamers, tetramers, and dimers, indicating flexibility in oligomerization. This flexibility, also found for other NDPK isoforms, has been correlated with the ability of this enzyme to interact with other proteins. We believe that the mtNDPK is involved in heat stress response in pea, possibly as a modulator of the 86-kD protein.

“…19G222000) with DNA binding domains (HLH, and Zinc binding) were also found in Pfam analysis. These domains were predicted to play a role as transcription factor as like HSF genes (Downs and Heckathorn 1998;Baniwal et al 2004). Chytochrome P450 domains found in up regulations in both cultivars.…”

Section: Discussionmentioning

confidence: 99%

Expression of Heat Shock Proteins by Heat Stress in Soybean

Song

Yim

Lee

2017

Plant Breed. Biotech.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Heat stress is one of the factors disturb productivity and growth of plants. Many genes including heat shock protein (HSP), heat shock transcription factors (HSF) and chaperones, were identified and characterized in many plants to play role in increased tolerance to abiotic stress. To reveal responsive gene to heat stress, we performed RNA-seq using two Korean soybean varieties under heat stress and normal conditions. The transcripts were analyzed, and we obtained 2,458 genes including 46 co-up regulation and 55 co-down regulated genes in both soybean varieties. We also revealed HSPs, HSFs and chaperones in the differentially expressed genes using BLAST and Pfam analyzation and verified expression changes under heat stress. Finally, we find 68 genes involved in HSP, HSF, chaperones in heat responsive genes associated increasing heat tolerance. As a result, relatively small HSP families were up regulated and continuously expressed in long period heat stress. On the other hand, large molecule HSPs, HSFs and chaperonin did not response to long heat stress. The expression profiling and characterization provide invaluable information to understand heat tolerance of soybean.