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Leydon AR, Downing B, Sanchez JS, Loll-Krippleber R, Belliveau NM, Rodriguez-Mias RA, Bauer A, Watson IJ, Bae L, Villén J, Brown GW, Nemhauser JL. A conserved function of corepressors is to nucleate assembly of the transcriptional preinitiation complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.587599. [PMID: 38617365 PMCID: PMC11014602 DOI: 10.1101/2024.04.01.587599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The plant corepressor TPL is recruited to diverse chromatin contexts, yet its mechanism of repression remains unclear. Previously, we have leveraged the fact that TPL retains its function in a synthetic transcriptional circuit in the yeast model Saccharomyces cerevisiae to localize repressive function to two distinct domains. Here, we employed two unbiased whole genome approaches to map the physical and genetic interactions of TPL at a repressed locus. We identified SPT4, SPT5 and SPT6 as necessary for repression with the SPT4 subunit acting as a bridge connecting TPL to SPT5 and SPT6. We also discovered the association of multiple additional constituents of the transcriptional preinitiation complex at TPL-repressed promoters, specifically those involved in early transcription initiation events. These findings were validated in yeast and plants through multiple assays, including a novel method to analyze conditional loss of function of essential genes in plants. Our findings support a model where TPL nucleates preassembly of the transcription activation machinery to facilitate rapid onset of transcription once repression is relieved.
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Affiliation(s)
| | - Benjamin Downing
- Department of Biology, University of Washington, Seattle, 98195, USA
| | | | | | | | | | - Andrew Bauer
- Department of Biology, University of Washington, Seattle, 98195, USA
| | | | - Lena Bae
- Department of Biology, University of Washington, Seattle, 98195, USA
| | - Judit Villén
- Department of Genome Sciences, University of Washington, Seattle, 98195, USA
| | - Grant W. Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto, Toronto, Ontario, CA
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Leydon AR, Wang W, Gala HP, Gilmour S, Juarez-Solis S, Zahler ML, Zemke JE, Zheng N, Nemhauser JL. Repression by the Arabidopsis TOPLESS corepressor requires association with the core mediator complex. eLife 2021; 10:66739. [PMID: 34075876 PMCID: PMC8203292 DOI: 10.7554/elife.66739] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/31/2021] [Indexed: 02/06/2023] Open
Abstract
The plant corepressor TOPLESS (TPL) is recruited to a large number of loci that are selectively induced in response to developmental or environmental cues, yet the mechanisms by which it inhibits expression in the absence of these stimuli are poorly understood. Previously, we had used the N-terminus of Arabidopsis thaliana TPL to enable repression of a synthetic auxin response circuit in Saccharomyces cerevisiae (yeast). Here, we leveraged the yeast system to interrogate the relationship between TPL structure and function, specifically scanning for repression domains. We identified a potent repression domain in Helix 8 located within the CRA domain, which directly interacted with the Mediator middle module subunits Med21 and Med10. Interactions between TPL and Mediator were required to fully repress transcription in both yeast and plants. In contrast, we found that multimer formation, a conserved feature of many corepressors, had minimal influence on the repression strength of TPL.
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Affiliation(s)
| | - Wei Wang
- Department of Pharmacology, Seattle, United States
| | - Hardik P Gala
- Department of Biology, University of Washington, Seattle, United States
| | - Sabrina Gilmour
- Department of Biology, University of Washington, Seattle, United States
| | | | - Mollye L Zahler
- Department of Biology, University of Washington, Seattle, United States
| | - Joseph E Zemke
- Department of Biology, University of Washington, Seattle, United States
| | - Ning Zheng
- Department of Pharmacology, Seattle, United States.,Howard Hughes Medical Institute, University of Washington, Seattle, United States
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Fonin AV, Darling AL, Kuznetsova IM, Turoverov KK, Uversky VN. Multi-functionality of proteins involved in GPCR and G protein signaling: making sense of structure-function continuum with intrinsic disorder-based proteoforms. Cell Mol Life Sci 2019; 76:4461-4492. [PMID: 31428838 PMCID: PMC11105632 DOI: 10.1007/s00018-019-03276-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 12/21/2022]
Abstract
GPCR-G protein signaling system recognizes a multitude of extracellular ligands and triggers a variety of intracellular signaling cascades in response. In humans, this system includes more than 800 various GPCRs and a large set of heterotrimeric G proteins. Complexity of this system goes far beyond a multitude of pair-wise ligand-GPCR and GPCR-G protein interactions. In fact, one GPCR can recognize more than one extracellular signal and interact with more than one G protein. Furthermore, one ligand can activate more than one GPCR, and multiple GPCRs can couple to the same G protein. This defines an intricate multifunctionality of this important signaling system. Here, we show that the multifunctionality of GPCR-G protein system represents an illustrative example of the protein structure-function continuum, where structures of the involved proteins represent a complex mosaic of differently folded regions (foldons, non-foldons, unfoldons, semi-foldons, and inducible foldons). The functionality of resulting highly dynamic conformational ensembles is fine-tuned by various post-translational modifications and alternative splicing, and such ensembles can undergo dramatic changes at interaction with their specific partners. In other words, GPCRs and G proteins exist as sets of conformational/basic, inducible/modified, and functioning proteoforms characterized by a broad spectrum of structural features and possessing various functional potentials.
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Affiliation(s)
- Alexander V Fonin
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - April L Darling
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Irina M Kuznetsova
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - Konstantin K Turoverov
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
- Department of Biophysics, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya av. 29, St. Petersburg, 195251, Russian Federation
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow, Russian Federation.
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