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Hsf1 yeast

Charles Nj Ravarani, Tamara Y Erkina, Greet De Baets, Daniel C Dudman, Alexandre M Erkine, M Madan Babu
Over 40% of proteins in any eukaryotic genome encode intrinsically disordered regions (IDRs) that do not adopt defined tertiary structures. Certain IDRs perform critical functions, but discovering them is non-trivial as the biological context determines their function. We present IDR-Screen, a framework to discover functional IDRs in a high-throughput manner by simultaneously assaying large numbers of DNA sequences that code for short disordered sequences. Functionality-conferring patterns in their protein sequence are inferred through statistical learning...
May 14, 2018: Molecular Systems Biology
Jordi Pujols, Jaime Santos, Irantzu Pallarès, Salvador Ventura
Response mechanisms to external stress rely on networks of proteins able to activate specific signaling pathways to ensure the maintenance of cell proteostasis. Many of the proteins mediating this kind of response contain intrinsically disordered regions, which lack a defined structure, but still are able to interact with a wide range of clients that modulate the protein function. Some of these interactions are mediated by specific short sequences embedded in the longer disordered regions. Because the physicochemical properties that promote functional and abnormal interactions are similar, it has been shown that, in globular proteins, aggregation-prone and binding regions tend to overlap...
May 6, 2018: International Journal of Molecular Sciences
Amanda O Veri, Zhengqiang Miao, Rebecca S Shapiro, Faiza Tebbji, Teresa R O'Meara, Sang Hu Kim, Juan Colazo, Kaeling Tan, Valmik K Vyas, Malcolm Whiteway, Nicole Robbins, Koon Ho Wong, Leah E Cowen
The capacity to respond to temperature fluctuations is critical for microorganisms to survive within mammalian hosts, and temperature modulates virulence traits of diverse pathogens. One key temperature-dependent virulence trait of the fungal pathogen Candida albicans is its ability to transition from yeast to filamentous growth, which is induced by environmental cues at host physiological temperature. A key regulator of temperature-dependent morphogenesis is the molecular chaperone Hsp90, which has complex functional relationships with the transcription factor Hsf1...
March 2018: PLoS Genetics
Xu Zheng, Ali Beyzavi, Joanna Krakowiak, Nikit Patel, Ahmad S Khalil, David Pincus
Clonal populations of cells exhibit cell-to-cell variation in the transcription of individual genes. In addition to this noise in gene expression, heterogeneity in the proteome and the proteostasis network expands the phenotypic diversity of a population. Heat shock factor 1 (Hsf1) regulates chaperone gene expression, thereby coupling transcriptional noise to proteostasis. Here we show that cell-to-cell variation in Hsf1 activity is an important determinant of phenotypic plasticity. Budding yeast cells with high Hsf1 activity were enriched for the ability to acquire resistance to an antifungal drug, and this enrichment depended on Hsp90, a known phenotypic capacitor and canonical Hsf1 target...
March 20, 2018: Cell Reports
Vinesh Vinayachandran, Rohit Reja, Matthew J Rossi, Bongsoo Park, Lila Rieber, Chitvan Mittal, Shaun Mahony, B Franklin Pugh
Gene expression is controlled by a variety of proteins that interact with the genome. Their precise organization and mechanism of action at every promoter remains to be worked out. To better understand the physical interplay among genome-interacting proteins, we examined the temporal binding of a functionally diverse subset of these proteins: nucleosomes (H3), H2AZ (Htz1), SWR (Swr1), RSC (Rsc1, Rsc3, Rsc58, Rsc6, Rsc9, Sth1), SAGA (Spt3, Spt7, Ubp8, Sgf11), Hsf1, TFIID (Spt15/TBP and Taf1), TFIIB (Sua7), TFIIH (Ssl2), FACT (Spt16), Pol II (Rpb3), and Pol II carboxyl-terminal domain (CTD) phosphorylation at serines 2, 5, and 7...
February 14, 2018: Genome Research
Eric J Solís, Jai P Pandey, Xu Zheng, Dexter X Jin, Piyush B Gupta, Edoardo M Airoldi, David Pincus, Vladimir Denic
No abstract text is available yet for this article.
February 1, 2018: Molecular Cell
Joanna Krakowiak, Xu Zheng, Nikit Patel, Zoë A Feder, Jayamani Anandhakumar, Kendra Valerius, David S Gross, Ahmad S Khalil, David Pincus
Models for regulation of the eukaryotic heat shock response typically invoke a negative feedback loop consisting of the transcriptional activator Hsf1 and a molecular chaperone. Previously we identified Hsp70 as the chaperone responsible for Hsf1 repression and constructed a mathematical model that recapitulated the yeast heat shock response (Zheng et al., 2016). The model was based on two assumptions: dissociation of Hsp70 activates Hsf1, and transcriptional induction of Hsp70 deactivates Hsf1. Here we validate these assumptions...
February 2, 2018: ELife
Pengsong Li, Xiaofen Fu, Lei Zhang, Zhiyu Zhang, Jihong Li, Shizhong Li
Background: High temperature inhibits cell growth and ethanol fermentation of Saccharomyces cerevisiae . As a complex phenotype, thermotolerance usually involves synergistic actions of many genes, thereby being difficult to engineer. The overexpression of either endogenous or exogenous stress-related transcription factor genes in yeasts was found to be able to improve relevant stress tolerance of the hosts. Results: To increase ethanol yield of high-temperature fermentation, we constructed a series of strains of S...
2017: Biotechnology for Biofuels
Rupal I Mehta, Natalia Tsymbalyuk, Svetlana Ivanova, Jesse A Stokum, Kyoon Woo, Volodymyr Gerzanich, J Marc Simard
In nutrient restricted environments, the yeast endosulfines Igo1/2 are activated via TORC1 inhibition and function critically to initiate and coordinate the cellular stress response that promotes survival. We examined expression of αEnsa, the mammalian homolog of yeast endosulfines, in rat stroke. Prominent neuronal upregulation of αEnsa was identified in 3 patterns within the ischemic gradient: (1) neurons in GFAP-/HSF1+ cortex showed upregulation and near-complete nuclear translocation of αEnsa protein within hours of ischemic onset; (2) neurons in GFAP+/HSF1+ cortex showed upregulation in cytoplasm and nuclei that persisted for days; (3) neurons in GFAP+/HSF1- cortex showed delayed cytosolic-only upregulation that persisted for days...
October 1, 2017: Journal of Neuropathology and Experimental Neurology
Matthias C Truttmann, Xu Zheng, Leo Hanke, Jadyn R Damon, Monique Grootveld, Joanna Krakowiak, David Pincus, Hidde L Ploegh
Protein AMPylation is a conserved posttranslational modification with emerging roles in endoplasmic reticulum homeostasis. However, the range of substrates and cell biological consequences of AMPylation remain poorly defined. We expressed human and Caenorhabditis elegans AMPylation enzymes-huntingtin yeast-interacting protein E (HYPE) and filamentation-induced by cyclic AMP (FIC)-1, respectively-in Saccharomyces cerevisiae, a eukaryote that lacks endogenous protein AMPylation. Expression of HYPE and FIC-1 in yeast induced a strong cytoplasmic Hsf1-mediated heat shock response, accompanied by attenuation of protein translation, massive protein aggregation, growth arrest, and lethality...
January 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
Esben G Poulsen, Caroline Kampmeyer, Franziska Kriegenburg, Jens V Johansen, Kay Hofmann, Christian Holmberg, Rasmus Hartmann-Petersen
As a result of exposure to stress conditions, mutations, or defects during synthesis, cellular proteins are prone to misfold. To cope with such partially denatured proteins, cells mount a regulated transcriptional response involving the Hsf1 transcription factor, which drives the synthesis of molecular chaperones and other stress-relieving proteins. Here, we show that the fission yeast Schizosaccharomyces pombe orthologues of human BAG-1, Bag101, and Bag102, are Hsp70 co-chaperones that associate with 26S proteasomes...
January 2017: Cell Stress & Chaperones
Xu Zheng, Joanna Krakowiak, Nikit Patel, Ali Beyzavi, Jideofor Ezike, Ahmad S Khalil, David Pincus
Heat shock factor (Hsf1) regulates the expression of molecular chaperones to maintain protein homeostasis. Despite its central role in stress resistance, disease and aging, the mechanisms that control Hsf1 activity remain unresolved. Here we show that in budding yeast, Hsf1 basally associates with the chaperone Hsp70 and this association is transiently disrupted by heat shock, providing the first evidence that a chaperone repressor directly regulates Hsf1 activity. We develop and experimentally validate a mathematical model of Hsf1 activation by heat shock in which unfolded proteins compete with Hsf1 for binding to Hsp70...
November 10, 2016: ELife
David Pincus
Heat shock factor 1 (Hsf1) is a transcription factor that is often described as the master regulator of the heat shock response in all eukaryotes. However, due to its essentiality in yeast, Hsf1's contribution to the transcriptome under basal and heat shock conditions has never been directly determined. Using a chemical genetics approach that allowed rapid Hsf1 inactivation, my colleagues and I have recently shown that the bulk of the heat shock response is Hsf1 independent. Rather than inducing genes responsible for carrying out the various cellular processes required for adaptation to thermal stress, Hsf1 controls a dedicated set of chaperone protein genes devoted to restoring protein-folding homeostasis...
May 2017: Current Genetics
Eric J Solís, Jai P Pandey, Xu Zheng, Dexter X Jin, Piyush B Gupta, Edoardo M Airoldi, David Pincus, Vladimir Denic
Despite its eponymous association with the heat shock response, yeast heat shock factor 1 (Hsf1) is essential even at low temperatures. Here we show that engineered nuclear export of Hsf1 results in cytotoxicity associated with massive protein aggregation. Genome-wide analysis revealed that Hsf1 nuclear export immediately decreased basal transcription and mRNA expression of 18 genes, which predominately encode chaperones. Strikingly, rescuing basal expression of Hsp70 and Hsp90 chaperones enabled robust cell growth in the complete absence of Hsf1...
July 7, 2016: Molecular Cell
Jayamani Anandhakumar, Yara W Moustafa, Surabhi Chowdhary, Amoldeep S Kainth, David S Gross
Mediator is an evolutionarily conserved coactivator complex essential for RNA polymerase II transcription. Although it has been generally assumed that in Saccharomyces cerevisiae, Mediator is a stable trimodular complex, its structural state in vivo remains unclear. Using the "anchor away" (AA) technique to conditionally deplete select subunits within Mediator and its reversibly associated Cdk8 kinase module (CKM), we provide evidence that Mediator's tail module is highly dynamic and that a subcomplex consisting of Med2, Med3, and Med15 can be independently recruited to the regulatory regions of heat shock factor 1 (Hsf1)-activated genes...
July 15, 2016: Molecular and Cellular Biology
Han Feng, Wei Liu, Da Cheng Wang
Cells respond to various proteotoxic stimuli and maintain protein homeostasis through a conserved mechanism called the heat-shock response, which is characterized by the enhanced synthesis of heat-shock proteins. This response is mediated by heat-shock factors (HSFs). Four genes encoding HSF1-HSF4 exist in the genome of mammals. In this protein family, HSF1 is the orthologue of the single HSF in lower eukaryotic organisms and is the major regulator of the heat-shock response, while HSF2, which shows low sequence homology to HSF1, serves as a developmental regulator...
April 2016: Acta Crystallographica. Section F, Structural Biology Communications
Junsheng Yang, Xinxin Hao, Xiuling Cao, Beidong Liu, Thomas Nyström
Huntington disease (HD) is a neurological disorder caused by polyglutamine expansions in mutated Huntingtin (mHtt) proteins, rendering them prone to form inclusion bodies (IB). We report that in yeast, such IB formation is a factor-dependent process subjected to age-related decline. A genome-wide, high-content imaging approach, identified the E3 ubiquitin ligase, Ltn1 of the ribosome quality control complex (RQC) as a key factor required for IB formation, ubiquitination, and detoxification of model mHtt. The failure of ltn1∆ cells to manage mHtt was traced to another RQC component, Tae2, and inappropriate control of heat shock transcription factor, Hsf1, activity...
April 1, 2016: ELife
Srijit Das, Nitai Pada Bhattacharyya
Huntingtin interacting protein HYPK (Huntingtin Yeast Partner K) is an intrinsically unstructured protein having chaperone-like activity and can suppress mutant huntingtin aggregates and toxicity in cell model of Huntington's Disease (HD). Heat shock response is an adaptive mechanism of cells characterized by upregulation of heat shock proteins by heat-induced activation of heat shock factor 1 (HSF1). The trans-activation ability of HSF1 is arrested upon restoration of proteostasis. We earlier identified HYPK as a heat-inducible protein and transcriptional target of HSF1...
May 1, 2016: Experimental Cell Research
Marjorie Petitjean, Marie-Ange Teste, Jean M François, Jean-Luc Parrou
Trehalose is a stable disaccharide commonly found in nature, from bacteria to fungi and plants. For the model yeast Saccharomyces cerevisiae, claims that trehalose is a stress protectant were based indirectly either on correlation between accumulation of trehalose and high resistance to various stresses or on stress hypersensitivity of mutants deleted for TPS1, which encodes the first enzyme in trehalose biosynthetic pathway. Our goal was to investigate more directly which one, between trehalose and/or the Tps1 protein, may serve yeast cells to withstand exposure to stress...
June 26, 2015: Journal of Biological Chemistry
Thales P Ribeiro, Christiane Fernandes, Karen V Melo, Sarah S Ferreira, Josane A Lessa, Roberto W A Franco, Gerhard Schenk, Marcos D Pereira, Adolfo Horn
Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes...
March 2015: Free Radical Biology & Medicine
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