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Liu AY, Minetti CA, Remeta DP, Breslauer KJ, Chen KY. HSF1, Aging, and Neurodegeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1409:23-49. [PMID: 35995906 DOI: 10.1007/5584_2022_733] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome and maintenance of proteostasis as a protective mechanism in response to stress. Research in this particular area has accelerated dramatically over the past three decades following successful isolation, cloning, and characterization of HSF1. The intricate multi-protein complexes and transcriptional activation orchestrated by HSF1 are fundamental processes within the cellular QC machinery. Our primary focus is on the regulation and function of HSF1 in aging and neurodegenerative diseases (ND) which represent physiological and pathological states of dysfunction in protein QC. This chapter presents an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function viz-à-viz age-dependent and neuron-specific vulnerability to ND. We discuss the structural domains of HSF1 with emphasis on the intrinsically disordered regions and note that disease proteins associated with ND are often structurally disordered and exquisitely sensitive to changes in cellular environment as may occur during aging. We propose a hypothesis that age-dependent changes of the intrinsically disordered proteome likely hold answers to understand many of the functional, structural, and organizational changes of proteins and signaling pathways in aging - dysfunction of HSF1 and accumulation of disease protein aggregates in ND included.Structured AbstractsIntroduction: Heat shock factor 1 (HSF1) is a master transcription regulator that mediates the induction of heat shock protein chaperones for quality control (QC) of the proteome as a cyto-protective mechanism in response to stress. There is cumulative evidence of age-related deterioration of this QC mechanism that contributes to disease vulnerability. OBJECTIVES Herein we discuss the regulation and function of HSF1 as they relate to the pathophysiological changes of protein quality control in aging and neurodegenerative diseases (ND). METHODS We present an overview of HSF1 structural, functional, and energetic properties in healthy cells while addressing the deterioration of HSF1 function vis-à-vis age-dependent and neuron-specific vulnerability to neurodegenerative diseases. RESULTS We examine the impact of intrinsically disordered regions on the function of HSF1 and note that proteins associated with neurodegeneration are natively unstructured and exquisitely sensitive to changes in cellular environment as may occur during aging. CONCLUSIONS We put forth a hypothesis that age-dependent changes of the intrinsically disordered proteome hold answers to understanding many of the functional, structural, and organizational changes of proteins - dysfunction of HSF1 in aging and appearance of disease protein aggregates in neurodegenerative diseases included.
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Affiliation(s)
- Alice Y Liu
- Department of Cell Biology and Neuroscience, Rutgers The State University of New Jersey, Piscataway, NJ, USA.
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA.
| | - Conceição A Minetti
- Department of Chemistry and Chemical Biology, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - David P Remeta
- Department of Chemistry and Chemical Biology, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Kenneth J Breslauer
- Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers The State University of New Jersey, Piscataway, NJ, USA
| | - Kuang Yu Chen
- Department of Chemistry and Chemical Biology, Rutgers The State University of New Jersey, Piscataway, NJ, USA
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2
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Kinetic principles underlying pioneer function of GAGA transcription factor in live cells. Nat Struct Mol Biol 2022; 29:665-676. [PMID: 35835866 PMCID: PMC10177624 DOI: 10.1038/s41594-022-00800-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/27/2022] [Indexed: 11/09/2022]
Abstract
How pioneer factors interface with chromatin to promote accessibility for transcription control is poorly understood in vivo. Here, we directly visualize chromatin association by the prototypical GAGA pioneer factor (GAF) in live Drosophila hemocytes. Single-particle tracking reveals that most GAF is chromatin bound, with a stable-binding fraction showing nucleosome-like confinement residing on chromatin for more than 2 min, far longer than the dynamic range of most transcription factors. These kinetic properties require the full complement of GAF's DNA-binding, multimerization and intrinsically disordered domains, and are autonomous from recruited chromatin remodelers NURF and PBAP, whose activities primarily benefit GAF's neighbors such as Heat Shock Factor. Evaluation of GAF kinetics together with its endogenous abundance indicates that, despite on-off dynamics, GAF constitutively and fully occupies major chromatin targets, thereby providing a temporal mechanism that sustains open chromatin for transcriptional responses to homeostatic, environmental and developmental signals.
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Kmiecik SW, Mayer MP. Molecular mechanisms of heat shock factor 1 regulation. Trends Biochem Sci 2021; 47:218-234. [PMID: 34810080 DOI: 10.1016/j.tibs.2021.10.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/08/2021] [Accepted: 10/22/2021] [Indexed: 02/06/2023]
Abstract
To thrive and to fulfill their functions, cells need to maintain proteome homeostasis even in the face of adverse environmental conditions or radical restructuring of the proteome during differentiation. At the center of the regulation of proteome homeostasis is an ancient transcriptional mechanism, the so-called heat shock response (HSR), orchestrated in all eukaryotic cells by heat shock transcription factor 1 (Hsf1). As Hsf1 is implicated in aging and several pathologies like cancer and neurodegenerative disorders, understanding the regulation of Hsf1 could open novel therapeutic opportunities. In this review, we discuss the regulation of Hsf1's transcriptional activity by multiple layers of control circuits involving Hsf1 synthesis and degradation, conformational rearrangements and post-translational modifications (PTMs), and molecular chaperones in negative feedback loops.
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Affiliation(s)
- Szymon W Kmiecik
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH-Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Matthias P Mayer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH-Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
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4
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Jacob P, Brisou G, Dalmais M, Thévenin J, van der Wal F, Latrasse D, Suresh Devani R, Benhamed M, Dubreucq B, Boualem A, Lepiniec L, Immink RGH, Hirt H, Bendahmane A. The Seed Development Factors TT2 and MYB5 Regulate Heat Stress Response in Arabidopsis. Genes (Basel) 2021; 12:genes12050746. [PMID: 34063415 PMCID: PMC8156827 DOI: 10.3390/genes12050746] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/30/2021] [Accepted: 05/10/2021] [Indexed: 11/16/2022] Open
Abstract
HEAT SHOCK FACTOR A2 (HSFA2) is a regulator of multiple environmental stress responses required for stress acclimation. We analyzed HSFA2 co-regulated genes and identified 43 genes strongly co-regulated with HSFA2 during multiple stresses. Motif enrichment analysis revealed an over-representation of the site II element (SIIE) in the promoters of these genes. In a yeast 1-hybrid screen with the SIIE, we identified the closely related R2R3-MYB transcription factors TT2 and MYB5. We found overexpression of MYB5 or TT2 rendered plants heat stress tolerant. In contrast, tt2, myb5, and tt2/myb5 loss of function mutants showed heat stress hypersensitivity. Transient expression assays confirmed that MYB5 and TT2 can regulate the HSFA2 promoter together with the other members of the MBW complex, TT8 and TRANSPARENT TESTA GLABRA 1 (TTG1) and that the SIIE was involved in this regulation. Transcriptomic analysis revealed that TT2/MYB5 target promoters were enriched in SIIE. Overall, we report a new function of TT2 and MYB5 in stress resistance and a role in SIIE-mediated HSFA2 regulation.
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Affiliation(s)
- Pierre Jacob
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Gwilherm Brisou
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Marion Dalmais
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Johanne Thévenin
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (J.T.); (B.D.); (L.L.)
| | - Froukje van der Wal
- Bioscience and Laboratory of Molecular Biology, Wageningen University and Research, 6708PB Wageningen, The Netherlands; (F.v.d.W.); (R.G.H.I.)
| | - David Latrasse
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Ravi Suresh Devani
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Moussa Benhamed
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Bertrand Dubreucq
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (J.T.); (B.D.); (L.L.)
| | - Adnane Boualem
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
| | - Loic Lepiniec
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (J.T.); (B.D.); (L.L.)
| | - Richard G. H. Immink
- Bioscience and Laboratory of Molecular Biology, Wageningen University and Research, 6708PB Wageningen, The Netherlands; (F.v.d.W.); (R.G.H.I.)
| | - Heribert Hirt
- Darwin21, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia;
- Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris-Saclay, Université Paris-Saclay, Univ. Evry, INRAE, CNRS, 91405 Orsay, France; (P.J.); (G.B.); (M.D.); (D.L.); (R.S.D.); (M.B.); (A.B.)
- Correspondence:
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Polidano J, Vankadari N, Price JT, Wilce JA. Detailed protocol for optimised expression and purification of functional monomeric human Heat Shock Factor 1. Protein Expr Purif 2020; 176:105722. [PMID: 32768454 DOI: 10.1016/j.pep.2020.105722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 11/16/2022]
Abstract
Heat Shock Factor 1 (HSF1) is the master regulator of the heat shock response, a universal survival mechanism throughout eukaryotic species used to buffer potentially lethal proteotoxic conditions. HSF1's function in vivo is regulated by several factors, including post translational modifications and elevated temperatures, whereupon it forms trimers to bind with heat shock elements in DNA. Unsurprisingly, HSF1 is also extremely sensitive to elevated temperatures in vitro, which poses specific technical challenges when producing HSF1 using a recombinant expression system. Although there are several useful publications which outline steps taken for HSF1 expression and purification, studies that describe specific strategies and detailed protocols to overcome HSF1 trimerisation and degradation are currently lacking. Herein, we have reported our detailed experimental protocol for the expression and purification of monomeric human HSF1 (HsHSF1) as a major species. We also propose a refined method of inducing HsHSF1 activation in vitro, that we consider more accurately mimics HsHSF1 activation in vivo and is therefore more physiologically relevant.
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Affiliation(s)
- Joseph Polidano
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia; Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria, 3800, Australia; Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St. Albans, VIC, Australia
| | - Naveen Vankadari
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria, 3800, Australia
| | - John T Price
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia; Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria, 3800, Australia; Institute for Health and Sport, Victoria University, Melbourne, Victoria, Australia; Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St. Albans, VIC, Australia
| | - Jacqueline A Wilce
- Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Victoria, 3800, Australia.
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6
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Zhang J, Pearson JZ, Gorbet GE, Cölfen H, Germann MW, Brinton MA, Demeler B. Spectral and Hydrodynamic Analysis of West Nile Virus RNA-Protein Interactions by Multiwavelength Sedimentation Velocity in the Analytical Ultracentrifuge. Anal Chem 2017; 89:862-870. [PMID: 27977168 PMCID: PMC5505516 DOI: 10.1021/acs.analchem.6b03926] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Interactions between nucleic acids and proteins are critical for many cellular processes, and their study is of utmost importance to many areas of biochemistry, cellular biology, and virology. Here, we introduce a new analytical method based on sedimentation velocity (SV) analytical ultracentrifugation, in combination with a novel multiwavelength detector to characterize such interactions. We identified the stoichiometry and molar mass of a complex formed during the interaction of a West Nile virus RNA stem loop structure with the human T cell-restricted intracellular antigen-1 related protein. SV has long been proven as a powerful technique for studying dynamic assembly processes under physiological conditions in solution. Here, we demonstrate, for the first time, how the new multiwavelength technology can be exploited to study protein-RNA interactions, and show how the spectral information derived from the new detector complements the traditional hydrodynamic information from analytical ultracentrifugation. Our method allows the protein and nucleic acid signals to be separated by spectral decomposition such that sedimentation information from each individual species, including any complexes, can be clearly identified based on their spectral signatures. The method presented here extends to any interacting system where the interaction partners are spectrally separable.
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Affiliation(s)
- Jin Zhang
- Georgia State University, Department of Chemistry, 50 Decatur St. SE, Atlanta, Georgia 30303, United States
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Joseph Z. Pearson
- University of Konstanz, Department of Chemistry, Physical Chemistry, Universitätsstraße 10, Box 714, D-78457 Konstanz, Germany
| | - Gary E. Gorbet
- The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7760, San Antonio, Texas 78229-3901, United States
| | - Helmut Cölfen
- University of Konstanz, Department of Chemistry, Physical Chemistry, Universitätsstraße 10, Box 714, D-78457 Konstanz, Germany
| | - Markus W. Germann
- Georgia State University, Department of Chemistry, 50 Decatur St. SE, Atlanta, Georgia 30303, United States
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Margo A. Brinton
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Borries Demeler
- The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7760, San Antonio, Texas 78229-3901, United States
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7
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Chan SF, He JG, Chu KH, Sun CB. The Shrimp Heat Shock Cognate 70 Functions as a Negative Regulator in Vitellogenin Gene Expression1. Biol Reprod 2014; 91:14. [DOI: 10.1095/biolreprod.113.117200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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8
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Park JK, Kim SJ. Equilibrium Binding of Wild-type and Mutant Drosophila Heat Shock Factor DNA Binding Domain with HSE DNA Studied by Analytical Ultracentrifugation. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.6.1839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Anckar J, Sistonen L. Regulation of HSF1 function in the heat stress response: implications in aging and disease. Annu Rev Biochem 2011; 80:1089-115. [PMID: 21417720 DOI: 10.1146/annurev-biochem-060809-095203] [Citation(s) in RCA: 532] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
To dampen proteotoxic stresses and maintain protein homeostasis, organisms possess a stress-responsive molecular machinery that detects and neutralizes protein damage. A prominent feature of stressed cells is the increased synthesis of heat shock proteins (Hsps) that aid in the refolding of misfolded peptides and restrain protein aggregation. Transcriptional activation of the heat shock response is orchestrated by heat shock factor 1 (HSF1), which rapidly translocates to hsp genes and induces their expression. Although the role of HSF1 in protecting cells and organisms against severe stress insults is well established, many aspects of how HSF1 senses qualitatively and quantitatively different forms of stresses have remained poorly understood. Moreover, recent discoveries that HSF1 controls life span have prompted new ways of thinking about an old transcription factor. Here, we review the established role of HSF1 in counteracting cell stress and prospect the role of HSF1 as a regulator of disease states and aging.
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Affiliation(s)
- Julius Anckar
- Department of Biosciences, Åbo Akademi University, BioCity, 20520 Turku, Finland.
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10
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Abstract
Protein kinase R (PKR) is a central component of the interferon antiviral defense pathway. Upon binding to dsRNA, PKR undergoes autophosphorylation reactions that activate the kinase, resulting in the inhibition of protein synthesis in virally-infected cells. We have used analytical ultracentrifugation and related biophysical methods to quantitatively characterize the stoichiometries, affinities, and free energy couplings that govern the assembly of the macromolecular complexes in the PKR activation pathway. These studies demonstrate that PKR dimerization play a key role in enzymatic activation and support a model where the role of dsRNA is to bring two or more PKR monomers in close proximity to enhance dimerization.
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Affiliation(s)
- James L Cole
- Department of Molecular and Cell Biology, National Analytical Ultracentrifugation Facility, University of Connecticut, Storrs, CT 06269, USA.
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11
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Ucci JW, Cole JL. Global analysis of non-specific protein-nucleic interactions by sedimentation equilibrium. Biophys Chem 2004; 108:127-40. [PMID: 15043926 PMCID: PMC2924682 DOI: 10.1016/j.bpc.2003.10.033] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protein-nucleic acid interactions govern a variety of processes, including replication, transcription, recombination and repair. These interactions take place in both sequence-specific and non-specific modes, and the latter occur in many biologically significant contexts. Analytical ultracentrifugation is a useful method for the detailed characterization of the stoichiometry and affinity of macromolecular interactions in free solution. There has been a resurgence of interest in the application of sedimentation equilibrium methods to protein-nucleic acid interactions. However, these studies have been generally focused on sequence-specific interactions. Here we describe an approach to analyze non-specific interactions using sedimentation equilibrium. We have adapted an existing model for non-specific interaction of proteins with finite, one-dimensional nucleic acid lattices for global fitting of multiwavelength sedimentation equilibrium data. The model is extended to accommodate protein binding to multiple faces of the nucleic acid, resulting in overlap of consecutive ligands along the sequence of the RNA or DNA. The approach is illustrated in a sedimentation equilibrium analysis of the interaction of the double-stranded RNA binding motif of protein kinase R with a 20-basepair RNA construct.
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Affiliation(s)
- Jason W. Ucci
- Department of Molecular and Cell Biology, University of Connecticut Storrs, Connecticut 06269
| | - James L. Cole
- Department of Molecular and Cell Biology, University of Connecticut Storrs, Connecticut 06269
- National Analytical Ultracentrifugation Facility, University of Connecticut, Storrs, Connecticut 06269
- To whom correspondence may be addressed: Department of Molecular and Cell Biology, 75 N. Eagleville Rd., U-3125, University of Connecticut, Storrs, Connecticut 06269, Phone: (860) 486-4333, FAX: (860) 486-4331,
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12
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Affiliation(s)
- James L Cole
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA
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13
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Cassiday LA, Lebruska LL, Benson LM, Naylor S, Owen WG, Maher LJ. Binding stoichiometry of an RNA aptamer and its transcription factor target. Anal Biochem 2002; 306:290-7. [PMID: 12123668 DOI: 10.1006/abio.2002.5710] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
RNA molecules serve informational, structural, and catalytic roles in cells. RNA also offers an interesting raw material for the design or genetic selection of modifiers of gene expression. We have been interested in the possibility that natural and/or artificial RNA ligands might be identified for DNA-binding proteins. With these concepts in mind, our laboratory previously isolated a 31-nucleotide RNA aptamer that specifically binds to human transcription factor NF-kappaB. This RNA aptamer (alpha-p50) competitively inhibits DNA binding by NF-kappaB in vitro. The aptamer may target the DNA-binding groove formed by the junction of the two monomers of NF-kappaB, perhaps mimicking kappaB duplex DNA. This model predicts a binding stoichiometry of one RNA aptamer per NF-kappaB dimer. To test this hypothesis, two complementary biophysical methods were utilized. Both analytical ultracentrifugation and microelectrospray mass spectrometry suggest that 1 mol of alpha-p50 RNA binds per mole of NF-kappaB p50 homodimer. Such a result is consistent with the observed ability of the RNA aptamer to block the access of transcription factor NF-kappaB to its binding site on DNA and highlights the question of how an RNA stem-loop structurally mimics a DNA duplex. This work also demonstrates the successful application of mass spectrometry to characterize noncovalent RNA/protein interactions.
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Affiliation(s)
- Laura A Cassiday
- Department of Biochemistry and Molecular Biology, Mayo Foundation, Rochester, Minnesota 55905, USA
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14
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Arkin M, Lear JD. A new data analysis method to determine binding constants of small molecules to proteins using equilibrium analytical ultracentrifugation with absorption optics. Anal Biochem 2001; 299:98-107. [PMID: 11726190 DOI: 10.1006/abio.2001.5396] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In principle, equilibrium analytical ultracentrifugation (AU) can be used to quantify the binding stoichiometry and affinity between small-molecule ligands and proteins in aqueous solution. We show here that heteromeric binding constants can be determined using a data-fitting procedure which utilizes a postfitting computation of the total amount of each component in the centrifuge cell. The method avoids overconstraining the fitting of the radial concentration profiles, but still permits unique binding constants to be determined using measurements at a single wavelength. The computational program is demonstrated by applying it to data obtained with mixtures of a 500-Da molecule and interleukin-2, a 16-kDa protein. The 1:1 binding stoichiometry and heteromeric dissociation constants (K(ab)) determined from centrifuge data at two different wavelengths are within the 4-9 microM range independently determined from a functional assay. Values for K(ab) have been obtained for ligands with affinities as weak as 500 microM. This AU method is applicable to compounds with significant UV absorbance (approximately 0.2) at concentrations within approximately 5- to 10-fold of their K(ab). The method, which has been incorporated into a user procedure for IgorPro (Wavemetrics, Oswego, OR), is included as supplementary material.
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Affiliation(s)
- M Arkin
- Sunesis Pharmaceuticals Inc., 341 Oyster Point Boulevard, South San Francisco, California 94080, USA
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15
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Littlefield O, Nelson HC. Crystal packing interaction that blocks crystallization of a site-specific DNA binding protein-DNA complex. Proteins 2001; 45:219-28. [PMID: 11599025 DOI: 10.1002/prot.1142] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present here three high-resolution crystal structures of complexes between the DNA-binding domain of the heat-shock transcription factor (HSF) and DNA oligomers. Although the DNA oligomers contain HSF's specific binding sequence, called a heat-shock element, the crystal structures do not contain the specific protein-DNA complex. In one crystal structure, the 10 base pair DNA oligomer is statically disordered. In the other two related structures, the 12 base pair DNA oligomers are in unique positions, but the protein-DNA contacts in these two crystals are not sequence specific. In all three structures, the DNA appears to act as a rigid, polyanion scaffold to support columns of proteins in a crystalline lattice. A robust crystal packing interface between protein monomers obscures the true DNA-binding surface, known from previous genetic and biochemical studies. By redesigning the protein to interfere with the crystal lattice contacts, we were able to obtain physiologically relevant crystals in a specific protein-DNA complex. Thus, a crystal-packing interface was able to prevent the weak, but physiological relevant interactions between a protein and DNA.
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Affiliation(s)
- O Littlefield
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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16
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Lardans V, Ram D, Lantner F, Ziv E, Schechter I. Differences in DNA-sequence recognition between the DNA-binding domain fragment and the full-length molecule of the heat-shock transcription factor of schistosome. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1519:230-4. [PMID: 11418190 DOI: 10.1016/s0167-4781(01)00220-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Binding and inhibition studies reveal that the DNA-binding domain (DBD) fragment and the full-length molecule of the heat-shock transcription factor of schistosome (SmHSF) differ in DNA sequence recognition. SmHSF does not recognize the ideal HSE consensus sequence (nGAAnnTTCnnGAAn) but recognizes a variant HSE that contains nGTAn instead of nGAAn in the third pentamer. The DBD reacts efficiently with the ideal HSE sequence and with lower affinity with the variant HSE sequence. These findings suggest that elements inside and outside the DBD contribute to the DNA-binding specificity of HSF.
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Affiliation(s)
- V Lardans
- Department of Immunology, The Weizmann Institute of Science, 76100, Rehovot, Israel
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Wills PR, Jacobsen MP, Winzor DJ. Analysis of sedimentation equilibrium distributions reflecting nonideal macromolecular associations. Biophys J 2000; 79:2178-87. [PMID: 11023922 PMCID: PMC1301108 DOI: 10.1016/s0006-3495(00)76466-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A rigorous statistical-mechanical approach is adopted to derive general quantitative expressions that allow for the effects of thermodynamic nonideality in equilibrium measurements reflecting interaction between dissimilar macromolecular reactants. An analytical procedure based on these expressions is then formulated for obtaining global estimates of equilibrium constants and the corresponding reference thermodynamic activities of the free reactants in each of several sedimentation equilibrium experiments. The method is demonstrated by application to results from an ultracentrifugal study of an electrostatic interaction between ovalbumin and cytochrome c (Winzor, D. J., M. P. Jacobsen, and P. R. Wills. 1998. Biochemistry. 37:2226-2233). It is demonstrated that reliable estimates of relevant thermodynamic parameters are extracted from the data through statistical analysis by means of a simple nonlinear fitting procedure.
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Affiliation(s)
- P R Wills
- Department of Physics, University of Auckland, Auckland, New Zealand
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18
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Affiliation(s)
- J Liu
- Department of Pharmaceutical Research and Development, Genentech, Inc., South San Francisco, California 94080, USA
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19
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Farkas T, Kutskova YA, Zimarino V. Intramolecular repression of mouse heat shock factor 1. Mol Cell Biol 1998; 18:906-18. [PMID: 9447987 PMCID: PMC108802 DOI: 10.1128/mcb.18.2.906] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The pathway leading to transcriptional activation of heat shock genes involves a step of heat shock factor 1 (HSF1) trimerization required for high-affinity binding of this activator protein to heat shock elements (HSEs) in the promoters. Previous studies have shown that in vivo the trimerization is negatively regulated at physiological temperatures by a mechanism that requires multiple hydrophobic heptad repeats (HRs) which may form a coiled coil in the monomer. To investigate the minimal requirements for negative regulation, in this work we have examined mouse HSF1 translated in rabbit reticulocyte lysate or extracted from Escherichia coli after limited expression. We show that under these conditions HSF1 behaves as a monomer which can be induced by increases in temperature to form active HSE-binding trimers and that mutations of either HR region cause activation in both systems. Furthermore, temperature elevations and acidic buffers activate purified HSF1, and mild proteolysis excises fragments which form HSE-binding oligomers. These results suggest that oligomerization can be repressed in the monomer, as previously proposed, and that repression can be relieved in the apparent absence of regulatory proteins. An intramolecular mechanism may be central for the regulation of this transcription factor in mammalian cells, although not necessarily sufficient.
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Affiliation(s)
- T Farkas
- Biological and Technological Research Department (DIBIT), San Raffaele Scientific Institute, Milan, Italy
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20
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Drees BL, Grotkopp EK, Nelson HC. The GCN4 leucine zipper can functionally substitute for the heat shock transcription factor's trimerization domain. J Mol Biol 1997; 273:61-74. [PMID: 9367746 DOI: 10.1006/jmbi.1997.1283] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The heat shock transcription factor (HSF) is the only known sequence-specific, homotrimeric DNA-binding protein. HSF binds to a DNA recognition site called a heat shock element (HSE), which contains varying numbers of nGAAn units ("GAA boxes") arranged in inverted repeats. To investigate the role of trimerization on HSF's DNA-binding properties, we replaced the trimerization domain, which self-assembles to form a three-stranded alpha-helical coiled coil, with the GCN4 leucine zipper, which forms a two-stranded alpha-helical coiled coil. Surprisingly, this substitution did not effect the ability of HSF to function in vivo. Biochemical studies of an HSF-leucine zipper chimera in comparison to an HSF truncation show that the HSF-leucine zipper chimera, though dimeric in solution and dimeric when bound to a two-box HSE, forms a trimeric complex when bound to a three-box HSE. The ability to form trimers depends on the presence of three contiguous GAA boxes present in inverted repeats. The proximity of the leucine zippers due to the orientation of the binding sites suggests that the leucine zippers might be forming a three-stranded coiled coil and several experiments lend support to this model. The ability of the leucine zipper to change oligomeric states in context might explain why the leucine zipper can replace the trimerization domain of HSF in vivo.
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Affiliation(s)
- B L Drees
- University of California, Department of Molecular and Cell Biology, Berkeley 94720-3206, USA
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21
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Jedlicka P, Mortin MA, Wu C. Multiple functions of Drosophila heat shock transcription factor in vivo. EMBO J 1997; 16:2452-62. [PMID: 9171358 PMCID: PMC1169845 DOI: 10.1093/emboj/16.9.2452] [Citation(s) in RCA: 223] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Heat shock transcription factor (HSF) is a transcriptional activator of heat shock protein (hsp) genes in eukaryotes. In order to elucidate the physiological functions of HSF in Drosophila, we have isolated lethal mutations in the hsf gene. Using a conditional allele, we show that HSF has an essential role in the ability of the organism to survive extreme heat stress. In contrast to previous results obtained with yeast HSF, the Drosophila protein is dispensable for general cell growth or viability. However, it is required under normal growth conditions for oogenesis and early larval development. These two developmental functions of Drosophila HSF are genetically separable and appear not to be mediated through the induction of HSPs, implicating a novel action of HSF that may be unrelated to its characteristic function as a stress-responsive transcriptional activator.
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Affiliation(s)
- P Jedlicka
- Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
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22
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Falke JJ, Bass RB, Butler SL, Chervitz SA, Danielson MA. The two-component signaling pathway of bacterial chemotaxis: a molecular view of signal transduction by receptors, kinases, and adaptation enzymes. Annu Rev Cell Dev Biol 1997; 13:457-512. [PMID: 9442881 PMCID: PMC2899694 DOI: 10.1146/annurev.cellbio.13.1.457] [Citation(s) in RCA: 437] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The chemosensory pathway of bacterial chemotaxis has become a paradigm for the two-component superfamily of receptor-regulated phosphorylation pathways. This simple pathway illustrates many of the fundamental principles and unanswered questions in the field of signaling biology. A molecular description of pathway function has progressed rapidly because it is accessible to diverse structural, biochemical, and genetic approaches. As a result, structures are emerging for most of the pathway elements, biochemical studies are elucidating the mechanisms of key signaling events, and genetic methods are revealing the intermolecular interactions that transmit information between components. Recent advances include (a) the first molecular picture of a conformational transmembrane signal in a cell surface receptor, (b) four new structures of kinase domains and adaptation enzymes, and (c) significant new insights into the mechanisms of receptor-mediated kinase regulation, receptor adaptation, and the phospho-activation of signaling proteins. Overall, the chemosensory pathway and the propulsion system it regulates provide an ideal system in which to probe molecular principles underlying complex cellular signaling and behavior.
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Affiliation(s)
- J J Falke
- Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215, USA.
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23
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Abstract
Heat shock transcription factors (HSFs) of higher eukaryotes respond to physical and cellular stress signals by trimerizing, binding to a specific site on DNA, and transactivating genes encoding the heat shock proteins. In this work, limited proteolysis was used as a biochemical probe of the domain organization of Drosophila HSF. Both unshocked monomeric and heat-shocked trimeric HSF possess an internal protease-sensitive region located between the amino-terminal and carboxyl-terminal hydrophobic heatad repeats, suggesting that this is a less structured region compared to those defined for DNA-binding, trimerization, and transactivation. For a few cleavage sites, the heat-shocked form of HSF is more accessible to proteases than the unshocked form, providing an additional diagnostic marker for inducible changes in conformation or modification between the latent and activated forms of HSF.
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Affiliation(s)
- M Zhong
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892-4255, USA
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24
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Orosz A, Wisniewski J, Wu C. Regulation of Drosophila heat shock factor trimerization: global sequence requirements and independence of nuclear localization. Mol Cell Biol 1996; 16:7018-30. [PMID: 8943357 PMCID: PMC231705 DOI: 10.1128/mcb.16.12.7018] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Heat shock transcription factor (HSF) is a multidomain protein that exists as a monomer under normal conditions and is reversibly induced upon heat shock to a trimeric state that binds to DNA with high affinity. The maintenance of the monomeric state is dependent on hydrophobic heptad repeats located at the amino- and carboxy-terminal regions which have been proposed to form an intramolecular coiled-coil structure. In a systematic deletion analysis to identify other regions of HSF that may be required to regulate its oligomeric state, we have found that local sequences encompassing the carboxy-terminal end of the DNA binding domain and a broad region of HSF between the heptad repeats also contribute to this regulation. Immunocytochemical analysis of mutant HSF proteins revealed a canonical motif required for nuclear localization. HSF proteins lacking the nuclear localization signal remain in the cytoplasm, but these HSFs nonetheless exhibit reversible heat stress-inducible trimerization. The results indicate that the signals that regulate HSF trimerization operate in both the nuclear and cytoplasmic compartments of the cell.
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Affiliation(s)
- A Orosz
- Laboratory of Molecular Cell Biology, National Cancer Institute, Bethesda, Maryland 20892-4255, USA
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25
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Abstract
The use of the biophysical technique of analytical ultracentrifugation has recently undergone a resurgence. The commercial availability of the Beckman optima XL-A and XL-I analytical ultracentrifuges along with the continued growth in computing ability and analysis software has led to the expanded use of analytical ultracentrifugation and its capabilities. The genetic revolution and the search for further understanding of macromolecular interactions have again brought analytical ultracentrifugation to the forefront of macromolecular characterization.
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Affiliation(s)
- T M Schuster
- Department of Molecular & Cell Biology, University of Connecticut, Storrs 06269-3125, USA.
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26
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Shopland LS, Lis JT. HSF recruitment and loss at most Drosophila heat shock loci is coordinated and depends on proximal promoter sequences. Chromosoma 1996; 105:158-71. [PMID: 8781184 DOI: 10.1007/bf02509497] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The heat shock response in Drosophila is primarily dependent on the binding of the heat shock transcription factor, HSF, to conserved sequences in heat shock gene promoters, the heat shock elements (HSEs). Here we examine the kinetic relationship of HSF binding to chromosomal loci and heat shock gene transcription in vivo. The features of heat shock promoters that determine the kinetics of HSF binding are also examined. Analyses of HSF association by indirect immunofluorescence with an anti-HSF antibody reveal that fluorescent signals at many loci on polytene chromosomes rapidly increase and then gradually decrease as heat shock time progresses. While overall amounts of fluorescent signal vary from locus to locus, the patterns of acquisition and loss of HSF at most loci are coordinated with only one identified exception. Immunostaining with an anti-RNA polymerase II antibody indicates that the kinetics of RNA polymerase II accumulation on the heat shock loci are similar to those of HSF. Furthermore, nuclear run-on assays confirm that the major heat shock genes are coordinately transcribed during the attenuation period. In contrast, the kinetics of HSF association with HSE "polymers" in a transgenic fly strain are not coordinated with those of endogenous loci. The addition of core promoter sequences to one of the HSEs found in the polymer restores coordinate HSF binding, suggesting that the kinetic patterns of HSF binding depend on a core promoter located near the HSEs. Finally, the distribution of the heat shock protein HSP70 is examined for its role in regulating the attenuated response of HSF to heat shock.
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Affiliation(s)
- L S Shopland
- Section of Biochemistry, Molecular and Cell Biology, 417 Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
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27
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Abstract
The science of chemistry has made considerable advances over the last few hundred years in the characterization of "small" molecules which can be purified and studied by melting, distillation, crystallization and solubility in various liquids. When the study of "large" natural and biological molecules, limited in these properties, rose in significance at the turn of the century, it was first attempted to explain their properties by the concepts of colloid chemistry of aggregation and complex formation. The struggle for the acceptance of the concept of the natural or biological covalently bonded macromolecule, as recalled by Herman Mark, is one of the interesting chapters in recent science history. A specific phase in the establishment of the macromolecular concept centered around the development by The Svedberg of the analytical ultracentrifuge, a versatile tool of highly practical and profound thermodynamic significance.
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Affiliation(s)
- H Eisenberg
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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28
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Schultheiss J, Kunert O, Gase U, Scharf KD, Nover L, Rüterjans H. Solution structure of the DNA-binding domain of the tomato heat-stress transcription factor HSF24. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 236:911-21. [PMID: 8665913 DOI: 10.1111/j.1432-1033.1996.00911.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Two-dimensional-NMR and three-dimensional-NMR experiments were performed to determine the solution structure of the DNA-binding domain of the tomato heat-stress transcription factor HSF24. Samples of uniformly 15N-labeled and 15N, 13C-labeled recombinant proteins were used in the investigation. A near-complete assignment of the backbone 1H, 15N, and 13C resonances was obtained by three-dimensional triple-resonance experiments, whereas three-dimensional 15N-TOCSY-heteronuclear-single-quantum-correlation-spectroscopy, HCCH-COSY and HCCH-TOCSY spectra were recorded for side-chain assignments, 885 non-redundant distance constraints from two-dimensional-homonuclear and three-dimensional-15N-edited and 13C-edited NOESY spectra and 40 hydrogen-bond constraints from exchange experiments were used for structure calculations. The resulting three-dimensional structure contains a three-helix bundle and a small four-stranded antiparallel beta-sheet that forms a hydrophobic core. The two C-terminal helices are parts of a highly conserved helix-turn-helix motif that is probably involved in DNA recognition and binding. In contrast to heat-stress factors from yeast and animals, the plant heat-stress factors lack a loop of 11 amino acid residues inserted between beta3 and beta4. This leads to a tight turn between these beta-strands.
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Affiliation(s)
- J Schultheiss
- Department of Biophysical Chemistry, Biocenter of the Goethe-Universität, Frankfurt, Germany
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29
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Balagurumoorthy P, Sakamoto H, Lewis MS, Zambrano N, Clore GM, Gronenborn AM, Appella E, Harrington RE. Four p53 DNA-binding domain peptides bind natural p53-response elements and bend the DNA. Proc Natl Acad Sci U S A 1995; 92:8591-5. [PMID: 7567980 PMCID: PMC41012 DOI: 10.1073/pnas.92.19.8591] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Recent structural studies of the minimal core DNA-binding domain of p53 (p53DBD) complexed to a single consensus pentamer sequence and of the isolated p53 tetramerization domain have provided valuable insights into their functions, but many questions about their interacting roles and synergism remain unanswered. To better understand these relationships, we have examined the binding of the p53DBD to two biologically important full-response elements (the WAF1 and ribosomal gene cluster sites) by using DNA circularization and analytical ultracentrifugation. We show that the p53DBD binds DNA strongly and cooperatively with p53DBD to DNA binding stoichiometries of 4:1. For the WAF1 element, the mean apparent Kd is (8.3 +/- 1.4) x 10(-8) M, and no intermediate species of lower stoichiometries can be detected. We show further that complex formation induces an axial bend of at least 60 degrees in both response elements. These results, taken collectively, demonstrate that p53DBD possesses the ability to direct the formation of a tight nucleoprotein complex having the same 4:1 DNA-binding stoichiometry as wild-type p53 which is accompanied by a substantial conformational change in the response-element DNA. This suggests that the p53DBD may play a role in the tetramerization function of p53. A possible role in this regard is proposed.
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Affiliation(s)
- P Balagurumoorthy
- Department of Biochemistry, University of Nevada Reno 89557-0014, USA
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30
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Torres FA, Bonner JJ. Genetic identification of the site of DNA contact in the yeast heat shock transcription factor. Mol Cell Biol 1995; 15:5063-70. [PMID: 7651423 PMCID: PMC230753 DOI: 10.1128/mcb.15.9.5063] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The heat shock transcription factor (HSF), a trimeric transcription factor, activates the expression of heat shock genes in eukaryotes. We have isolated mutations in the HSF1 gene from Saccharomyces cerevisiae that severely compromise the ability of HSF to bind to its normal binding site, repeats of the module nGAAn. One of these mutations, Q229R, shows a "new specificity" phenotype, in which the protein prefers the mutant sequence nGACn. These results identify the region of HSF that contacts DNA, in complete agreement with the crystal structure of HSF of Kluyveromyces lactis and the nuclear magnetic resonance data from HSF of Drosophila melanogaster. To determine the orientation of the DNA-binding domain on the nGAAn motif, we performed site-specific cross-linking between cysteine residues of single-cysteine substitutions. Cysteines placed at the N terminus of the DNA contact helix formed cross-links readily, while cysteines placed at the C terminus of the helix did not.
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Affiliation(s)
- F A Torres
- Department of Biology, Indiana University, Bloomington 47405, USA
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31
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Hansen JC, Lebowitz J, Demeler B. Analytical ultracentrifugation of complex macromolecular systems. Biochemistry 1994; 33:13155-63. [PMID: 7947722 DOI: 10.1021/bi00249a001] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J C Hansen
- Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284-7760
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32
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Interaction between heat shock factor and hsp70 is insufficient to suppress induction of DNA-binding activity in vivo. Mol Cell Biol 1994. [PMID: 7935376 DOI: 10.1128/mcb.14.10.6552] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular level of free heat shock proteins, in particular the 70-kDa stress protein family, has been suggested to be the basis of an autoregulatory mechanism by which the cell measures the level of thermal stress and regulates the synthesis of heat shock proteins. It has been proposed that the DNA-binding and oligomeric state of the heat shock transcription factor (HSF) is a principal step in the induction pathway that is responsive to the level of 70-kDa stress protein. To test this hypothesis, we investigated the association between HSF and 70-kDa stress protein by means of a coimmunoprecipitation assay. We found that 70-kDa stress proteins associate to similar extents with both latent and active forms of HSF, although unlike other 70-kDa stress protein substrates, the association with HSF was not significantly disrupted in the presence of ATP. Gel mobility shift assays indicated that active HSF trimers purified from a bacterial expression system could not be substantially deactivated in vitro with purified 70-kDa stress protein and ATP. In addition, elevated concentrations of hsp70 alone could not significantly inhibit induction of the DNA-binding activity of endogenous HSF in cultured rat cells, and the induction was also not inhibited in cultured rat cells or Drosophila cells containing elevated levels of all members of the heat shock protein family. However, the deactivation of HSF to the non-DNA-binding state after prolonged heat stress or during recovery could be accelerated by increased levels of heat shock proteins. Hence, the level of heat shock proteins may affect the rate of disassembly of HSF trimers, but another mechanism, as yet undefined, appears to control the onset of the oligomeric transitions.
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33
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Rabindran SK, Wisniewski J, Li L, Li GC, Wu C. Interaction between heat shock factor and hsp70 is insufficient to suppress induction of DNA-binding activity in vivo. Mol Cell Biol 1994; 14:6552-60. [PMID: 7935376 PMCID: PMC359185 DOI: 10.1128/mcb.14.10.6552-6560.1994] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The intracellular level of free heat shock proteins, in particular the 70-kDa stress protein family, has been suggested to be the basis of an autoregulatory mechanism by which the cell measures the level of thermal stress and regulates the synthesis of heat shock proteins. It has been proposed that the DNA-binding and oligomeric state of the heat shock transcription factor (HSF) is a principal step in the induction pathway that is responsive to the level of 70-kDa stress protein. To test this hypothesis, we investigated the association between HSF and 70-kDa stress protein by means of a coimmunoprecipitation assay. We found that 70-kDa stress proteins associate to similar extents with both latent and active forms of HSF, although unlike other 70-kDa stress protein substrates, the association with HSF was not significantly disrupted in the presence of ATP. Gel mobility shift assays indicated that active HSF trimers purified from a bacterial expression system could not be substantially deactivated in vitro with purified 70-kDa stress protein and ATP. In addition, elevated concentrations of hsp70 alone could not significantly inhibit induction of the DNA-binding activity of endogenous HSF in cultured rat cells, and the induction was also not inhibited in cultured rat cells or Drosophila cells containing elevated levels of all members of the heat shock protein family. However, the deactivation of HSF to the non-DNA-binding state after prolonged heat stress or during recovery could be accelerated by increased levels of heat shock proteins. Hence, the level of heat shock proteins may affect the rate of disassembly of HSF trimers, but another mechanism, as yet undefined, appears to control the onset of the oligomeric transitions.
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Affiliation(s)
- S K Rabindran
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892
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34
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Solution structure of the DNA-binding domain of Drosophila heat shock transcription factor. Nat Struct Mol Biol 1994. [DOI: 10.1038/nsb0994-605] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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Hubl ST, Owens JC, Nelson HC. Mutational analysis of the DNA-binding domain of yeast heat shock transcription factor. NATURE STRUCTURAL BIOLOGY 1994; 1:615-20. [PMID: 7634101 DOI: 10.1038/nsb0994-615] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Both randomized oligonucleotide cassette mutagenesis and site-directed mutagenesis have been used in combination with a yeast genetic screen to identify critical residues in the DNA-binding domain of heat shock transcription factor from Saccharomyces cerevisiae. Most of the surface residues in this highly conserved domain can be changed to alanine with no observable effect on function. Of nine critical residues identified in this screen, five are within helix alpha 3, previously designated as the probable DNA recognition helix in the crystal structure of the Kluyveromyces lactis protein. The other four residues may be involved in DNA-binding or protein-protein interactions.
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Affiliation(s)
- S T Hubl
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3206, USA
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