Interaction of oxidized chaperonin GroEL with an unfolded protein at low temperatures

2012 ◽  
Vol 32 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Girish C. Melkani ◽  
Robin Sielaff ◽  
Gustavo Zardeneta ◽  
Jose A. Mendoza
Keyword(s):  
Atpase Activity ◽  
Low Temperatures ◽  
Hydrophobic Interactions ◽  
Hydrophobic Surfaces ◽  
Unfolded Protein ◽  
Native Proteins ◽  
Chaperonin Groel ◽  
Excess Amount ◽  
Substrate Proteins

The chaperonin GroEL binds to non-native substrate proteins via hydrophobic interactions, preventing their aggregation, which is minimized at low temperatures. In the present study, we investigated the refolding of urea-denatured rhodanese at low temperatures, in the presence of ox-GroEL (oxidized GroEL), which contains increased exposed hydrophobic surfaces and retains its ability to hydrolyse ATP. We found that ox-GroEL could efficiently bind the urea-unfolded rhodanese at 4°C, without requiring excess amount of chaperonin relative to normal GroEL (i.e. non-oxidized). The release/reactivation of rhodanese from GroEL was minimal at 4°C, but was found to be optimal between 22 and 37°C. It was found that the loss of the ATPase activity of ox-GroEL at 4°C prevented the release of rhodanese from the GroEL–rhodanese complex. Thus ox-GroEL has the potential to efficiently trap recombinant or non-native proteins at 4°C and release them at higher temperatures under appropriate conditions.

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

scholarly journals Effect of Low-Temperature Stress On Na+/K+-ATPase and Transcriptome Changes in Oreochromis Niloticus Gill Tissues

2021 ◽  
Author(s):  
Zhe Li ◽  
Luting Wen ◽  
Xia Wu ◽  
Junqi Qin ◽  
Zhong Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Atpase Activity ◽  
Temperature Stress ◽  
Oreochromis Niloticus ◽  
Low Temperatures ◽  
Treatment Time ◽  
Low Temperature Stress ◽  
Receptor Interaction ◽  
Control Group ◽  
Material Transport

Abstract Low temperatures limit the development of Oreochromis niloticus (tilapia), and an increase in low-temperature tolerance would increase yields. We studied the responses of tilapia to low temperatures. The fish were labeled CK, AA, BB, and CC based on treatment (25°C, 12°C/1 h, 12°C/24 h, and 12°C/48 h, respectively) with CK being the control group. We examined the transcriptome responses and the Na+/K+-ATPase activity of gill tissue in each group. The Na+/K+-ATPase activity varied with the treatment time. Transcriptome sequencing of 12 individuals yielded 585.51 million clean reads, and at least 83.26% of the genes were mapped to the reference genome. Comparative analysis revealed 12,448 genes with significantly differential expression, including 792, 1,827, 1,924 upregulated genes and 992, 3,056, 3,857 genes downregulated for AA, BB, and CC, respectively. Differentially expressed genes (DEGs) were validated using RT-PCR for five genes. Functional annotation analysis of the DEGs identified functions associated with response to low-temperature stress. When tilapia was subjected to low-temperature stress, expression changes occurred in genes associated with cytokine-cytokine receptor interaction, metabolic pathways, cell adhesion molecules, material transport, and immunity. The founding will help understand the effects of low temperature on fish and provide a theoretical basis for the tilapia breeding industry.

scholarly journals Non-native proteins inhibit the ER oxidoreductin 1 (Ero1)–protein disulfide-isomerase relay when protein folding capacity is exceeded

2020 ◽  
Vol 295 (26) ◽  
pp. 8647-8655 ◽  
Author(s):  
Antti Moilanen ◽  
Lloyd W. Ruddock
Keyword(s):  
Protein Folding ◽  
Cross Talk ◽  
Protein Disulfide Isomerase ◽  
Feedback Inhibition ◽  
Inhibition Mechanism ◽  
Disulfide Isomerase ◽  
Unfolded Protein ◽  
Oxidative Protein Folding ◽  
Native Proteins ◽  
Protein Disulfide

Protein maturation in the endoplasmic reticulum (ER) depends on a fine balance between oxidative protein folding and quality control mechanisms, which together ensure high-capacity export of properly folded proteins from the ER. Oxidative protein folding needs to be regulated to avoid hyperoxidation. The folding capacity of the ER is regulated by the unfolded protein response (UPR) and ER-associated degradation (ERAD). The UPR is triggered by unfolded protein stress and leads to up-regulation of cellular components such as chaperones and folding catalysts. These components relieve stress by increasing folding capacity and up-regulating ERAD components that remove non-native proteins. Although oxidative protein folding and the UPR/ERAD pathways each are well-understood, very little is known about any direct cross-talk between them. In this study, we carried out comprehensive in vitro activity and binding assays, indicating that the oxidative protein folding relay formed by ER oxidoreductin 1 (Ero1), and protein disulfide-isomerase can be inactivated by a feedback inhibition mechanism involving unfolded proteins and folding intermediates when their levels exceed the folding capacity of the system. This mechanism allows client proteins to remain mainly in the reduced state and thereby minimizes potential futile oxidation–reduction cycles and may also enhance ERAD, which requires reduced protein substrates. Relief from excess levels of non-native proteins by increasing the levels of folding factors removed the feedback inhibition. These results reveal regulatory cross-talk between the oxidative protein folding and UPR and ERAD pathways.

Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex

2010 ◽  
Vol 427 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Tomoya Sameshima ◽  
Ryo Iizuka ◽  
Taro Ueno ◽  
Takashi Funatsu
Keyword(s):  
Energy Transfer ◽  
Atpase Activity ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Inhibitory Influence ◽  
Reaction Cycle ◽  
Chaperonin Groel ◽  
Denatured Proteins ◽  
Fluorescence Resonance

Controversy exists over whether the chaperonin GroEL forms a GroEL–(GroES)2 complex (football-shaped complex) during its reaction cycle. We have revealed previously the existence of the football-shaped complex in the chaperonin reaction cycle using a FRET (fluorescence resonance energy transfer) assay [Sameshima, Ueno, Iizuka, Ishii, Terada, Okabe and Funatsu (2008) J. Biol. Chem. 283, 23765–23773]. Although denatured proteins alter the ATPase activity of GroEL and the dynamics of the GroEL–GroES interaction, the effect of denatured proteins on the formation of the football-shaped complex has not been characterized. In the present study, a FRET assay was used to demonstrate that denatured proteins facilitate the formation of the football-shaped complex. The presence of denatured proteins was also found to increase the rate of association of GroES to the trans-ring of GroEL. Furthermore, denatured proteins decrease the inhibitory influence of ADP on ATP-induced association of GroES to the trans-ring of GroEL. From these findings we conclude that denatured proteins facilitate the dissociation of ADP from the trans-ring of GroEL and the concomitant association of ATP and the second GroES.

scholarly journals Structure of the Dimerization Domain of the Rabies Virus Phosphoprotein

2010 ◽  
Vol 84 (7) ◽  
pp. 3707-3710 ◽  
Author(s):  
Ivan Ivanov ◽  
Thibaut Crépin ◽  
Marc Jamin ◽  
Rob W. H. Ruigrok
Keyword(s):  
Crystal Structure ◽  
Rabies Virus ◽  
Vesicular Stomatitis Virus ◽  
Hydrophobic Interactions ◽  
Sendai Virus ◽  
Hydrophobic Surfaces ◽  
Dimerization Domain ◽  
Tetramerization Domain ◽  
Helical Hairpin ◽  
Vesicular Stomatitis

ABSTRACT The crystal structure of the dimerization domain of rabies virus phosphoprotein was determined. The monomer consists of two α-helices that make a helical hairpin held together mainly by hydrophobic interactions. The monomer has a hydrophilic and a hydrophobic face, and in the dimer two monomers pack together through their hydrophobic surfaces. This structure is very different from the dimerization domain of the vesicular stomatitis virus phosphoprotein and also from the tetramerization domain of the Sendai virus phosphoprotein, suggesting that oligomerization is conserved but not structure.

scholarly journals A novel cochaperonin that modulates the ATPase activity of cytoplasmic chaperonin.

1994 ◽  
Vol 125 (5) ◽  
pp. 989-996 ◽  
Author(s):  
Y Gao ◽  
R Melki ◽  
P D Walden ◽  
S A Lewis ◽  
C Ampe ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Beta Tubulin ◽  
Folding Process ◽  
Target Proteins ◽  
Chaperonin Groel ◽  
Significant Homology ◽  
Additional Protein ◽  
Cloned Cdna

The folding of alpha- and beta-tubulin requires three proteins: the heteromeric TCP-1-containing cytoplasmic chaperonin and two additional protein cofactors (A and B). We show that these cofactors participate in the folding process and do not merely trigger release, since in the presence of Mg-ATP alone, alpha- and beta-tubulin target proteins are discharged from cytoplasmic chaperonin in a nonnative form. Like the prokaryotic cochaperonin GroES, which interacts with the prototypical Escherichia coli chaperonin GroEL and regulates its ATPase activity, cofactor A modulates the ATPase activity of its cognate chaperonin. However, the sequence of cofactor A derived from a cloned cDNA defines a 13-kD polypeptide with no significant homology to other known proteins. Moreover, while GroES functions as a heptameric ring, cofactor A behaves as a dimer. Thus, cofactor A is a novel cochaperonin that is structurally unrelated to GroES.

Precipitation in Al-Alloy 6016 – The Role of Excess Vacancies

2012 ◽  
Vol 706-709 ◽  
pp. 317-322 ◽  
Author(s):  
Ahmad Falahati ◽  
Peter Lang ◽  
Ernst Kozeschnik
Keyword(s):  
Low Temperatures ◽  
Heat Treatments ◽  
Excess Vacancy ◽  
Al Alloy ◽  
Precipitation Sequence ◽  
Excess Amount ◽  
Superior Mechanical Properties ◽  
Basic Features ◽  
Novel Model

6xxx Al alloys owe their superior mechanical properties to the precipitation of finely dispersed metastable β´´ precipitates. These particles are formed in the course of optimized heat treatments, where the desired microstructure is generated in a sequence of precipitation processes going from MgSi co-clusters and GP zones to β´´ and β´ precipitates and finally to the stable β and Si diamond phases. The entire precipitation sequence occurs at relatively low temperatures (RT to approx. 200 °C) and is mainly controlled by the excess amount of quenched-in vacancies, which drive the diffusional processes at these low temperatures. Very recently a novel model for the prediction of the excess vacancy evolution controlled by the annihilation and generation of vacancies at dislocation jogs, grain boundaries and Frank loops was developed and implemented in the thermo-kinetic software MatCalc. In the present work, we explore the basic features of this model in the simulation of the excess vacancy evolution during technological heat treatments. The focus of this article lies on the effect of vacancy supersaturation during different heat treatment steps, such as quenching, heating, natural and artificial aging.

scholarly journals ERdj3, a Stress-inducible Endoplasmic Reticulum DnaJ Homologue, Serves as a CoFactor for BiP's Interactions with Unfolded Substrates

2005 ◽  
Vol 16 (1) ◽  
pp. 40-50 ◽  
Author(s):  
Ying Shen ◽  
Linda M. Hendershot
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Atpase Activity ◽  
Light Chain ◽  
Light Chains ◽  
Nonpermissive Temperature ◽  
Protein Substrates ◽  
Unfolded Protein

We recently identified ERdj3 as a component of unassembled immunoglobulin (Ig) heavy chain:BiP complexes. ERdj3 also associates with a number of other protein substrates, including unfolded light chains, a nonsecreted Ig light chain mutant, and the VSV-G ts045 mutant at the nonpermissive temperature. We produced an ERdj3 mutant that was unable to stimulate BiP's ATPase activity in vitro or to bind BiP in vivo. This mutant retained the ability to interact with unfolded protein substrates, suggesting that ERdj3 binds directly to proteins instead of via interactions with BiP. BiP remained bound to unfolded light chains longer than ERdj3, which interacted with unfolded light chains initially, but quickly disassociated before protein folding was completed. This suggests that ERdj3 may bind first to substrates and serve to inhibit protein aggregation until BiP joins the complex, whereas BiP remains bound until folding is complete. Moreover, our findings support a model where interactions with BiP help trigger the release of ERdj3 from the substrate:BiP complex.

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