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Reed Brendon Wickner, Evgeny E Bezsonov, Moonil Son, Mathieu Ducatez, Morgan Dewilde, Herman K Edskes
The amyloid-based yeast prions are folded in-register parallel beta sheet polymers. Each prion can exist in a wide array of variants, with different biological properties resulting from different self-propagating amyloid conformations. Yeast has several anti-prion systems, acting in normal cells (without protein overexpression or deficiency). Some anti-prion proteins partially block prion formation (Ssb1,2p - ribosome-associated Hsp70s), others cure a large portion of prion variants that arise (Btn2p, Cur1p, Hsp104 - a disaggregase, Siw14p, Upf1,2,3p - nonsense-mediated decay proteins) and others prevent prion-induced pathology (Sis1p - essential cytoplasmic Hsp40)...
January 29, 2018: Biochemistry
Xiaohong Zhao, Jenna Lanz, Danielle Steinberg, Tyler Pease, Joseph M Ahearn, Evgeny E Bezsonov, Elena Staguhn, Evan Eisenberg, Daniel C Masison, Lois E Greene
The [URE3] yeast prion is the self-propagating amyloid form of the Ure2 protein. [URE3] is cured by overexpression of several yeast proteins, including Ydj1, Btn2, Cur1, Hsp42, and human DnaJB6. To better understand [URE3] curing, we used real-time imaging with a yeast strain expressing a GFP-labeled full-length Ure2 construct to monitor the curing of [URE3] over time. [URE3] yeast cells exhibited numerous fluorescent foci, and expression of the GFP-labeled Ure2 affected neither mitotic stability of [URE3] nor the rate of [URE3] curing by the curing proteins...
January 12, 2018: Journal of Biological Chemistry
Lois E Greene, Xiaohong Zhao, Evan Eisenberg
The yeast [PSI+ ] prion, which is the amyloid form of Sup35, has the unusual property of being cured not only by the inactivation of, but also by the overexpression of Hsp104. Even though this latter observation was made more than two decades ago, the mechanism of curing by Hsp104 overexpression has remained controversial. This question has been investigated in depth by our laboratory by combining live cell imaging of GFP-labeled Sup35 with standard plating assays of yeast overexpressing Hsp104. We will discuss why the curing of [PSI+ ] by Hsp104 overexpression is not compatible with a mechanism of either inhibition of severing of the prion seeds or asymmetric segregation of the seeds...
February 2, 2018: Prion
Hui-Yong Lian, Kang-Wei Lin, Chuanjun Yang, Peng Cai
In this study, we studied the effect of 2.0 GHz radio frequency electromagnetic field (RF-EMF) and 50 Hz extremely low frequency electromagnetic field (ELF-EMF) exposure on prion generation and propagation using two budding yeast strains, NT64C and SB34, as model organisms. Under exposure to RF-EMF or ELF-EMF, the de novo generation and propagation of yeast prions [URE3] were elevated in both strains. The elevation increased over time, and the effects of ELF-EMF occurred in a dose-dependent manner. The transcription and expression levels of the molecular chaperones Hsp104, Hsp70-Ssa1/2, and Hsp40-Ydj1 were not statistically significantly changed after exposure...
December 6, 2017: Cell Stress & Chaperones
Jungsoon Lee, Nuri Sung, Lythou Yeo, Changsoo Chang, Sukyeong Lee, Francis T F Tsai
The ring-forming Hsp104 ATPase cooperates with Hsp70 and Hsp40 molecular chaperones to rescue stress-damaged proteins from both amorphous and amyloid-forming aggregates. The ability to do so relies upon pore loops present in the first ATP-binding domain (AAA-1; loop-1 and loop-2 ) and in the second ATP-binding domain (AAA-2; loop-3) of Hsp104, which face the protein translocating channel and couple ATP-driven changes in pore loop conformation to substrate translocation. A hallmark of loop-1 and loop-3 is an invariable and mutational sensitive aromatic amino acid (Tyr257 and Tyr662 ) involved in substrate binding...
December 22, 2017: Bioscience Reports
Ruoyun Li, Guotong Xiong, Shukun Yuan, Zufang Wu, Yingjie Miao, Peifang Weng
Saccharomyces cerevisiae has been widely used for wine fermentation and bio-fuels production. A S. cerevisiae strain Sc131 isolated from tropical fruit shows good fermentation properties and ethanol tolerance, exhibiting significant potential in Chinese bayberry wine fermentation. In this study, RNA-sequence and RT-qPCR was used to investigate the transcriptome profile of Sc131 in response to ethanol stress. Scanning Electron Microscopy were carried out to observe surface morphology of yeast cells. Totally, 937 genes were identified differential expressed, including 587 up-regulated and 350 down-regulated genes, after 4-h ethanol stress (10% v/v)...
November 3, 2017: World Journal of Microbiology & Biotechnology
Mark Rütgers, Ligia Segatto Muranaka, Timo Mühlhaus, Frederik Sommer, Sylvia Thoms, Juliane Schurig, Felix Willmund, Miriam Schulz-Raffelt, Michael Schroda
We have identified 39 proteins that interact directly or indirectly with high confidence with chloroplast HSP22E/F under heat stress thus revealing chloroplast processes affected by heat. Under conditions promoting protein unfolding, small heat shock proteins (sHsps) prevent the irreversible aggregation of unfolding proteins by integrating into forming aggregates. Aggregates containing sHsps facilitate the access of Hsp70 and ClpB/Hsp104 chaperones, which in ATP-dependent reactions disentangle individual proteins from the aggregates and assist in their refolding to the native state...
December 2017: Plant Molecular Biology
Fen Pei, Susanne DiSalvo, Suzanne S Sindi, Tricia R Serio
Prions adopt alternative, self-replicating protein conformations and thereby determine novel phenotypes that are often irreversible. Nevertheless, dominant-negative prion mutants can revert phenotypes associated with some conformations. These observations suggest that, while intervention is possible, distinct inhibitors must be developed to overcome the conformational plasticity of prions. To understand the basis of this specificity, we determined the impact of the G58D mutant of the Sup35 prion on three of its conformational variants, which form amyloids in S...
October 2017: PLoS Genetics
Marina Ptushkina, Toryn Poolman, Mudassar Iqbal, Mark Ashe, Janni Petersen, Joanna Woodburn, Magnus Rattray, Anthony Whetton, David Ray
The glucocorticoid receptor (GR) is essential for the stress response in mammals. We investigated potential non-transcriptional roles of GR in cellular stress response using fission yeast as a model.We surprisingly discovered marked heat stress resistance in yeast ectopically expressing human GR, which required expression of both the N-terminal transactivation domain, and the C-terminal ligand binding domain, but not the DNA-binding domain of the GR. This effect was not affected by GR ligand exposure, and occurred without significant GR nuclear accumulation...
September 21, 2017: Scientific Reports
Andrew G Matveenko, Yury A Barbitoff, Lina Manuela Jay-Garcia, Yury O Chernoff, Galina A Zhouravleva
Endogenous yeast amyloids that control heritable traits and are frequently used as models for human amyloid diseases are termed yeast prions. Yeast prions, including the best studied ones ([PSI (+)] and [URE3]), propagate via intimate interactions with molecular chaperones. Different yeast prions exhibit differential responses to changes in levels, functionality or localization of the components of chaperone machinery. Here, we provide additional data confirming differential effects of chaperones (and specifically, Hsp40s) on yeast prions and summarize current knowledge of the mechanisms underlying chaperone specificities...
September 20, 2017: Current Genetics
Reed B Wickner, Amy C Kelly, Evgeny E Bezsonov, Herman K Edskes
The yeast prions [PSI+] and [URE3] are folded in-register parallel β-sheet amyloids of Sup35p and Ure2p, respectively. In a screen for antiprion systems curing [PSI+] without protein overproduction, we detected Siw14p as an antiprion element. An array of genetic tests confirmed that many variants of [PSI+] arising in the absence of Siw14p are cured by restoring normal levels of the protein. Siw14p is a pyrophosphatase specifically cleaving the β phosphate from 5-diphosphoinositol pentakisphosphate (5PP-IP5), suggesting that increased levels of this or some other inositol polyphosphate favors [PSI+] propagation...
October 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
Jungsoon Lee, Nuri Sung, Jonathan M Mercado, Corey F Hryc, Changsoo Chang, Sukyeong Lee, Francis T F Tsai
Hsp104 is a ring-forming protein disaggregase that rescues stress-damaged proteins from an aggregated state. To facilitate protein disaggregation, Hsp104 cooperates with Hsp70 and Hsp40 chaperones (Hsp70/40) to form a bi-chaperone system. How Hsp104 recognizes its substrates, particularly the importance of the N domain, remains poorly understood and multiple, seemingly conflicting mechanisms have been proposed. Although the N domain is dispensable for protein disaggregation, it is sensitive to point mutations that abolish the function of the bacterial Hsp104 homolog in vitro, and is essential for curing yeast prions by Hsp104 overexpression in vivo...
September 11, 2017: Scientific Reports
Chan-Gi Pack, Yuji Inoue, Takashi Higurashi, Shigeko Kawai-Noma, Daigo Hayashi, Elizabeth Craig, Hideki Taguchi
Budding yeast has dozens of prions, which are mutually dependent on each other for the de novo prion formation. In addition to the interactions among prions, transmissions of prions are strictly dependent on two chaperone systems: the Hsp104 and the Hsp70/Hsp40 (J-protein) systems, both of which cooperatively remodel the prion aggregates to ensure the multiplication of prion entities. Since it has been postulated that prions and the remodeling factors constitute complex networks in cells, a quantitative approach to describe the interactions in live cells would be required...
September 2017: BMB Reports
Josielle Abrahão, David Z Mokry, Carlos H I Ramos
ATPases associated with diverse cellular activities (AAA+) form a superfamily of proteins involved in a variety of functions and are characterized by the presence of an ATPase module containing two conserved motifs known as Walker A and Walker B. ClpB and Hsp104, chaperones that have disaggregase activities, are members of a subset of this superfamily, known as the AAA family, and are characterized by the presence of a second highly conserved motif, known as the second region of homology (SRH). Hsp104 and its homolog Hsp78 (78 kDa heat shock protein) are representatives of the Clp family in yeast...
2017: Frontiers in Molecular Biosciences
Ilectra Adam, Lyne Jossé, Mick F Tuite
TorsinA (TorA) is an AAA+ (ATPases associated with diverse cellular activities) ATPase linked to dystonia type 1 (DYT1), a neurological disorder that leads to uncontrollable muscular movements. Although DYT1 is linked to a 3 bp deletion in the C-terminus of TorA, the biological function of TorA remains to be established. Here, we use the yeast Saccharomyces cerevisiae as a tractable in vivo model to explore TorA function. We demonstrate that TorA can protect yeast cells against different forms of environmental stress and show that in the absence of the molecular disaggregase Hsp104, TorA can refold heat-denatured luciferase in vivo in an ATP-dependent manner...
October 5, 2017: Biochemical Journal
Atiya Techaparin, Pornthap Thanonkeo, Preekamol Klanrit
OBJECTIVES: To investigate gene expression profiles of the thermotolerant yeast Saccharomyces cerevisiae strain KKU-VN8, a potential high-ethanol producer, in response to various stresses during high-temperature ethanol fermentation using sweet sorghum juice (SSJ) under optimal conditions. RESULTS: The maximal ethanol concentration obtained by S. cerevisiae KKU-VN8 using SSJ at 40 °C was 66.6 g/l, with a productivity of 1.39 g/l/h and a theoretical ethanol yield of 81%...
October 2017: Biotechnology Letters
Ju-Hwang Park, Hae Rim Jang, In Young Lee, Hye Kyung Oh, Eui-Ju Choi, Hyangshuk Rhim, Seongman Kang
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by motor neuron loss in the spinal cord and brain. Mutations in the superoxide dismutase 1 (SOD1) gene have been linked to familial ALS. To elucidate the role of SOD1 mutations in ALS, we investigated 14-3-3, a crucial regulator of cell death that was identified in patients with familial ALS. In a transgenic mouse model (SOD1-G93A) of ALS, 14-3-3 co-localized with mutant SOD1 aggregates and was more insoluble in the spinal cords of mutant SOD1 transgenic mice than in those of wild-type mice...
September 15, 2017: Human Molecular Genetics
Brian Cox, Mick Tuite
The AAA+ disaggregase Hsp104 is essential for the maintenance and inheritance of nearly all known prions of the yeast Saccharomyces cerevisiae. Uniquely for [PSI (+)], the prion form of the Sup35 protein, there seem to be two activities, involving differing co-chaperones, by which Hsp104 affects the inheritance of [PSI (+)], the prion form of the Sup35 protein. Each pathway is also involved in protection against ageing, one through disaggregation of damaged proteins and the other through their retention in the mother cell during budding...
June 26, 2017: Current Genetics
Hidenori Nakaoka, Yuichi Wakamoto
Replicative aging has been demonstrated in asymmetrically dividing unicellular organisms, seemingly caused by unequal damage partitioning. Although asymmetric segregation and inheritance of potential aging factors also occur in symmetrically dividing species, it nevertheless remains controversial whether this results in aging. Based on large-scale single-cell lineage data obtained by time-lapse microscopy with a microfluidic device, in this report, we demonstrate the absence of replicative aging in old-pole cell lineages of Schizosaccharomyces pombe cultured under constant favorable conditions...
June 2017: PLoS Biology
Tae Rin Oh, Jong Hum Kim, Seok Keun Cho, Moon Young Ryu, Seong Wook Yang, Woo Taek Kim
AtAIRP2 is a cytosolic RING-type E3 ubiquitin ligase that positively regulates an abscisic acid (ABA) response in Arabidopsis (Arabidopsis thaliana). Yeast two-hybrid screening using AtAIRP2 as bait identified ATP1 (AtAIRP2 Target Protein1) as a substrate of AtAIRP2. ATP1 was found to be identical to SDIRIP1, which was reported recently to be a negative factor in ABA signaling and a target protein of the RING E3 ligase SDIR1. Accordingly, ATP1 was renamed ATP1/SDIRIP1. A specific interaction between AtAIRP2 and ATP1/SDIRIP1 and ubiquitination of ATP1/SDIRIP1 by AtAIRP2 were demonstrated in vitro and in planta...
August 2017: Plant Physiology
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