1
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Pattelli ON, Valdivia EM, Beyersdorf MS, Regan CS, Rivas M, Hebert KA, Merajver SD, Cierpicki T, Mapp AK. A Lipopeptidomimetic of Transcriptional Activation Domains Selectively Disrupts the Coactivator Med25 Protein-Protein Interactions. Angew Chem Int Ed Engl 2024; 63:e202400781. [PMID: 38527936 PMCID: PMC11134611 DOI: 10.1002/anie.202400781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
Short amphipathic peptides are capable of binding to transcriptional coactivators, often targeting the same binding surfaces as native transcriptional activation domains. However, they do so with modest affinity and generally poor selectivity, limiting their utility as synthetic modulators. Here we show that incorporation of a medium-chain, branched fatty acid to the N-terminus of one such heptameric lipopeptidomimetic (LPPM-8) increases the affinity for the coactivator Med25 >20-fold (Ki >100 μM to 4 μM), rendering it an effective inhibitor of Med25 protein-protein interactions (PPIs). The lipid structure, the peptide sequence, and the C-terminal functionalization of the lipopeptidomimetic each influence the structural propensity of LPPM-8 and its effectiveness as an inhibitor. LPPM-8 engages Med25 through interaction with the H2 face of its activator interaction domain and in doing so stabilizes full-length protein in the cellular proteome. Further, genes regulated by Med25-activator PPIs are inhibited in a cell model of triple-negative breast cancer. Thus, LPPM-8 is a useful tool for studying Med25 and mediator complex biology and the results indicate that lipopeptidomimetics may be a robust source of inhibitors for activator-coactivator complexes.
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Affiliation(s)
- Olivia N. Pattelli
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Estefanía Martínez Valdivia
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Matthew S. Beyersdorf
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Clint S. Regan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
| | - Mónica Rivas
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
| | | | - Sofia D. Merajver
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Tomasz Cierpicki
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109 USA
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Anna K. Mapp
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109 USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 USA
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2
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Monté D, Lens Z, Dewitte F, Villeret V, Verger A. Assessment of machine-learning predictions for the Mediator complex subunit MED25 ACID domain interactions with transactivation domains. FEBS Lett 2024; 598:758-773. [PMID: 38436147 DOI: 10.1002/1873-3468.14837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/01/2024] [Accepted: 02/10/2024] [Indexed: 03/05/2024]
Abstract
The human Mediator complex subunit MED25 binds transactivation domains (TADs) present in various cellular and viral proteins using two binding interfaces, named H1 and H2, which are found on opposite sides of its ACID domain. Here, we use and compare deep learning methods to characterize human MED25-TAD interfaces and assess the predicted models to published experimental data. For the H1 interface, AlphaFold produces predictions with high-reliability scores that agree well with experimental data, while the H2 interface predictions appear inconsistent, preventing reliable binding modes. Despite these limitations, we experimentally assess the validity of MED25 interface predictions with the viral transcriptional activators Lana-1 and IE62. AlphaFold predictions also suggest the existence of a unique hydrophobic pocket for the Arabidopsis MED25 ACID domain.
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Affiliation(s)
- Didier Monté
- CNRS EMR 9002 Integrative Structural Biology, Inserm U 1167 - RID-AGE, Univ. Lille, CHU Lille, Institut Pasteur de Lille, France
| | - Zoé Lens
- CNRS EMR 9002 Integrative Structural Biology, Inserm U 1167 - RID-AGE, Univ. Lille, CHU Lille, Institut Pasteur de Lille, France
| | - Frédérique Dewitte
- CNRS EMR 9002 Integrative Structural Biology, Inserm U 1167 - RID-AGE, Univ. Lille, CHU Lille, Institut Pasteur de Lille, France
| | - Vincent Villeret
- CNRS EMR 9002 Integrative Structural Biology, Inserm U 1167 - RID-AGE, Univ. Lille, CHU Lille, Institut Pasteur de Lille, France
| | - Alexis Verger
- CNRS EMR 9002 Integrative Structural Biology, Inserm U 1167 - RID-AGE, Univ. Lille, CHU Lille, Institut Pasteur de Lille, France
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3
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Udupa A, Kotha SR, Staller MV. Commonly asked questions about transcriptional activation domains. Curr Opin Struct Biol 2024; 84:102732. [PMID: 38056064 PMCID: PMC11193542 DOI: 10.1016/j.sbi.2023.102732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 12/08/2023]
Abstract
Eukaryotic transcription factors activate gene expression with their DNA-binding domains and activation domains. DNA-binding domains bind the genome by recognizing structurally related DNA sequences; they are structured, conserved, and predictable from protein sequences. Activation domains recruit chromatin modifiers, coactivator complexes, or basal transcriptional machinery via structurally diverse protein-protein interactions. Activation domains and DNA-binding domains have been called independent, modular units, but there are many departures from modularity, including interactions between these regions and overlap in function. Compared to DNA-binding domains, activation domains are poorly understood because they are poorly conserved, intrinsically disordered, and difficult to predict from protein sequences. This review, organized around commonly asked questions, describes recent progress that the field has made in understanding the sequence features that control activation domains and predicting them from sequence.
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Affiliation(s)
- Aditya Udupa
- Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA
| | - Sanjana R Kotha
- Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA; Center for Computational Biology, University of California, Berkeley, 94720, USA
| | - Max V Staller
- Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA; Center for Computational Biology, University of California, Berkeley, 94720, USA; Chan Zuckerberg Biohub-San Francisco, San Francisco, CA 94158, USA.
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4
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Martinez TC, McNerney ME. Haploinsufficient Transcription Factors in Myeloid Neoplasms. ANNUAL REVIEW OF PATHOLOGY 2024; 19:571-598. [PMID: 37906947 DOI: 10.1146/annurev-pathmechdis-051222-013421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Many transcription factors (TFs) function as tumor suppressor genes with heterozygous phenotypes, yet haploinsufficiency generally has an underappreciated role in neoplasia. This is no less true in myeloid cells, which are normally regulated by a delicately balanced and interconnected transcriptional network. Detailed understanding of TF dose in this circuitry sheds light on the leukemic transcriptome. In this review, we discuss the emerging features of haploinsufficient transcription factors (HITFs). We posit that: (a) monoallelic and biallelic losses can have distinct cellular outcomes; (b) the activity of a TF exists in a greater range than the traditional Mendelian genetic doses; and (c) how a TF is deleted or mutated impacts the cellular phenotype. The net effect of a HITF is a myeloid differentiation block and increased intercellular heterogeneity in the course of myeloid neoplasia.
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Affiliation(s)
- Tanner C Martinez
- Department of Pathology, Department of Pediatrics, Section of Hematology/Oncology, The University of Chicago Medicine Comprehensive Cancer Center, The University of Chicago, Chicago, Illinois, USA;
- Medical Scientist Training Program, The University of Chicago, Chicago, Illinois, USA
| | - Megan E McNerney
- Department of Pathology, Department of Pediatrics, Section of Hematology/Oncology, The University of Chicago Medicine Comprehensive Cancer Center, The University of Chicago, Chicago, Illinois, USA;
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5
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Theisen FF, Prestel A, Elkjær S, Leurs YHA, Morffy N, Strader LC, O'Shea C, Teilum K, Kragelund BB, Skriver K. Molecular switching in transcription through splicing and proline-isomerization regulates stress responses in plants. Nat Commun 2024; 15:592. [PMID: 38238333 PMCID: PMC10796322 DOI: 10.1038/s41467-024-44859-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
The Arabidopsis thaliana DREB2A transcription factor interacts with the negative regulator RCD1 and the ACID domain of subunit 25 of the transcriptional co-regulator mediator (Med25) to integrate stress signals for gene expression, with elusive molecular interplay. Using biophysical and structural analyses together with high-throughput screening, we reveal a bivalent binding switch in DREB2A containing an ACID-binding motif (ABS) and the known RCD1-binding motif (RIM). The RIM is lacking in a stress-induced DREB2A splice variant with retained transcriptional activity. ABS and RIM bind to separate sites on Med25-ACID, and NMR analyses show a structurally heterogeneous complex deriving from a DREB2A-ABS proline residue populating cis- and trans-isomers with remote impact on the RIM. The cis-isomer stabilizes an α-helix, while the trans-isomer may introduce energetic frustration facilitating rapid exchange between activators and repressors. Thus, DREB2A uses a post-transcriptionally and post-translationally modulated switch for transcriptional regulation.
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Affiliation(s)
- Frederik Friis Theisen
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Prestel
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Steffie Elkjær
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Yannick H A Leurs
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Charlotte O'Shea
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kaare Teilum
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Karen Skriver
- The REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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6
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Liu Y, Joy ST, Henley MJ, Croskey A, Yates JA, Merajver SD, Mapp AK. Inhibition of CREB Binding and Function with a Dual-Targeting Ligand. Biochemistry 2024; 63:1-8. [PMID: 38086054 PMCID: PMC10836052 DOI: 10.1021/acs.biochem.3c00469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
CBP/p300 is a master transcriptional coactivator that regulates gene activation by interacting with multiple transcriptional activators. Dysregulation of protein-protein interactions (PPIs) between the CBP/p300 KIX domain and its activators is implicated in a number of cancers, including breast, leukemia, and colorectal cancer. However, KIX is typically considered "undruggable" because of its shallow binding surfaces lacking both significant topology and promiscuous binding profiles. We previously reported a dual-targeting peptide (MybLL-tide) that inhibits the KIX-Myb interaction with excellent specificity and potency. Here, we demonstrate a branched, second-generation analogue, CREBLL-tide, that inhibits the KIX-CREB PPI with higher potency and selectivity. Additionally, the best of these CREBLL-tide analogues shows excellent and selective antiproliferation activity in breast cancer cells. These results indicate that CREBLL-tide is an effective tool for assessing the role of KIX-activator interactions in breast cancer and expanding the dual-targeting strategy for inhibiting KIX and other coactivators that contain multiple binding surfaces.
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Affiliation(s)
- Yejun Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Stephen T Joy
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Madeleine J Henley
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Ayza Croskey
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joel A Yates
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Sofia D Merajver
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Anna K Mapp
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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7
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Pattelli ON, Valdivia EM, Beyersdorf MS, Regan CS, Rivas M, Merajver SD, Cierpicki T, Mapp AK. A lipopeptidomimetic of transcriptional activation domains selectively disrupts Med25 PPIs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.534168. [PMID: 36993479 PMCID: PMC10055422 DOI: 10.1101/2023.03.24.534168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Short amphipathic peptides are capable of binding to transcriptional coactivators, often targeting the same binding surfaces as native transcriptional activation domains. However, they do so with modest affinity and generally poor selectivity, limiting their utility as synthetic modulators. Here we show that incorporation of a medium-chain, branched fatty acid to the N-terminus of one such heptameric lipopeptidomimetic (34913-8) increases the affinity for the coactivator Med25 >10-fold ( Ki >>100 μM to 10 μM). Importantly, the selectivity of 34913-8 for Med25 compared to other coactivators is excellent. 34913-8 engages Med25 through interaction with the H2 face of its Ac tivator I nteraction D omain and in doing so stabilizes full-length protein in the cellular proteome. Further, genes regulated by Med25-activator PPIs are inhibited in a cell model of triple-negative breast cancer. Thus, 34913-8 is a useful tool for studying Med25 and the Mediator complex biology and the results indicate that lipopeptidomimetics may be a robust source of inhibitors for activator-coactivator complexes.
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8
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Richter WF, Nayak S, Iwasa J, Taatjes DJ. The Mediator complex as a master regulator of transcription by RNA polymerase II. Nat Rev Mol Cell Biol 2022; 23:732-749. [PMID: 35725906 PMCID: PMC9207880 DOI: 10.1038/s41580-022-00498-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2022] [Indexed: 02/08/2023]
Abstract
The Mediator complex, which in humans is 1.4 MDa in size and includes 26 subunits, controls many aspects of RNA polymerase II (Pol II) function. Apart from its size, a defining feature of Mediator is its intrinsic disorder and conformational flexibility, which contributes to its ability to undergo phase separation and to interact with a myriad of regulatory factors. In this Review, we discuss Mediator structure and function, with emphasis on recent cryogenic electron microscopy data of the 4.0-MDa transcription preinitiation complex. We further discuss how Mediator and sequence-specific DNA-binding transcription factors enable enhancer-dependent regulation of Pol II function at distal gene promoters, through the formation of molecular condensates (or transcription hubs) and chromatin loops. Mediator regulation of Pol II reinitiation is also discussed, in the context of transcription bursting. We propose a working model for Mediator function that combines experimental results and theoretical considerations related to enhancer-promoter interactions, which reconciles contradictory data regarding whether enhancer-promoter communication is direct or indirect. We conclude with a discussion of Mediator's potential as a therapeutic target and of future research directions.
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Affiliation(s)
- William F Richter
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Shraddha Nayak
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
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9
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Liu R, Niimi H, Ueda M, Takaoka Y. Coordinately regulated transcription factors EIN3/EIL1 and MYCs in ethylene and jasmonate signaling interact with the same domain of MED25. Biosci Biotechnol Biochem 2022; 86:1405-1412. [PMID: 35876657 DOI: 10.1093/bbb/zbac119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 07/05/2022] [Indexed: 11/15/2022]
Abstract
Ethylene (ET) and jasmonate (JA) are plant hormones that act synergistically to regulate plant development and defense against necrotrophic fungi infections, and antagonistically in response to wounds and apical hook formation. Previous studies revealed that the coordination of these responses is due to dynamic protein-protein interactions (PPI) between their master transcription factors (TFs) EIN3/EIL1 and MYC in ET and JA signaling, respectively. In addition, both TFs are activated via interactions with the same transcriptional mediator MED25, which upregulates downstream gene expression. Herein, we analyzed the PPI between EIN3/EIL1 and MED25, and as with the PPI between MYC3 and MED25, found that the short binding domain of MED25 (CMIDM) is also responsible for the interaction with EIN3/EIL1 - a finding which suggests that both TFs compete for binding with MED25. These results further inform our understanding of the coordination between the ET and JA regulatory systems.
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Affiliation(s)
- Ruiqi Liu
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Hikaru Niimi
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Minoru Ueda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
- Department of Molecular and Chemical Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Yousuke Takaoka
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan
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10
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Friis Theisen F, Salladini E, Davidsen R, Jo Rasmussen C, Staby L, Kragelund BB, Skriver K. αα-hub coregulator structure and flexibility determine transcription factor binding and selection in regulatory interactomes. J Biol Chem 2022; 298:101963. [PMID: 35452682 PMCID: PMC9127584 DOI: 10.1016/j.jbc.2022.101963] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 11/23/2022] Open
Abstract
Formation of transcription factor (TF)-coregulator complexes is a key step in transcriptional regulation, with coregulators having essential functions as hub nodes in molecular networks. How specificity and selectivity are maintained in these nodes remain open questions. In this work, we addressed specificity in transcriptional networks using complexes formed between TFs and αα-hubs, which are defined by a common αα-hairpin secondary structure motif, as a model. Using NMR spectroscopy and binding thermodynamics, we analyzed the structure, dynamics, stability, and ligand-binding properties of the Arabidopsis thaliana RST domains from TAF4 and known binding partner RCD1, and the TAFH domain from human TAF4, allowing comparison across species, functions, and architectural contexts. While these αα-hubs shared the αα-hairpin motif, they differed in length and orientation of accessory helices as well as in their thermodynamic profiles of ligand binding. Whereas biologically relevant RCD1-ligand pairs displayed high affinity driven by enthalpy, TAF4-ligand interactions were entropy driven and exhibited less binding-induced structuring. We in addition identified a thermal unfolding state with a structured core for all three domains, although the temperature sensitivity differed. Thermal stability studies suggested that initial unfolding of the RCD1-RST domain localized around helix 1, lending this region structural malleability, while effects in TAF4-RST were more stochastic, suggesting variability in structural adaptability upon binding. Collectively, our results support a model in which hub structure, flexibility, and binding thermodynamics contribute to αα-hub-TF binding specificity, a finding of general relevance to the understanding of coregulator-ligand interactions and interactome sizes.
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Affiliation(s)
- Frederik Friis Theisen
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Edoardo Salladini
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Rikke Davidsen
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Christina Jo Rasmussen
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Staby
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Karen Skriver
- REPIN and the Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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11
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Su BG, Henley MJ. Drugging Fuzzy Complexes in Transcription. Front Mol Biosci 2022; 8:795743. [PMID: 34993233 PMCID: PMC8724552 DOI: 10.3389/fmolb.2021.795743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/03/2021] [Indexed: 11/13/2022] Open
Abstract
Transcription factors (TFs) are one of the most promising but underutilized classes of drug targets. The high degree of intrinsic disorder in both the structure and the interactions (i.e., “fuzziness”) of TFs is one of the most important challenges to be addressed in this context. Here, we discuss the impacts of fuzziness on transcription factor drug discovery, describing how disorder poses fundamental problems to the typical drug design, and screening approaches used for other classes of proteins such as receptors or enzymes. We then speculate on ways modern biophysical and chemical biology approaches could synergize to overcome many of these challenges by directly addressing the challenges imposed by TF disorder and fuzziness.
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Affiliation(s)
- Bonnie G Su
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.,The Broad Institute of MIT and Harvard, Cambridge, MA, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Matthew J Henley
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.,The Broad Institute of MIT and Harvard, Cambridge, MA, United States
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12
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Hóbor F, Hegedüs Z, Ibarra AA, Petrovicz VL, Bartlett GJ, Sessions RB, Wilson AJ, Edwards TA. Understanding p300-transcription factor interactions using sequence variation and hybridization. RSC Chem Biol 2022; 3:592-603. [PMID: 35656479 PMCID: PMC9092470 DOI: 10.1039/d2cb00026a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/10/2022] [Indexed: 11/21/2022] Open
Abstract
The hypoxic response is central to cell function and plays a significant role in the growth and survival of solid tumours. HIF-1 regulates the hypoxic response by activating over 100...
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Affiliation(s)
- Fruzsina Hóbor
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane Leeds LS2 9JT UK
- School of Molecular and Cellular Biology, University of Leeds Woodhouse Lane Leeds LS2 9JT UK
| | - Zsófia Hegedüs
- Department of Medical Chemistry, University of Szeged Dóm tér 8 H-6720 Szeged Hungary
| | - Amaurys Avila Ibarra
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk Bristol BS8 1TD UK
- BrisSynBio, University of Bristol, Life Sciences Building Tyndall Avenue Bristol BS8 1TQ UK
| | - Vencel L Petrovicz
- Department of Medical Chemistry, University of Szeged Dóm tér 8 H-6720 Szeged Hungary
| | - Gail J Bartlett
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk Bristol BS8 1TD UK
- BrisSynBio, University of Bristol, Life Sciences Building Tyndall Avenue Bristol BS8 1TQ UK
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Richard B Sessions
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk Bristol BS8 1TD UK
- BrisSynBio, University of Bristol, Life Sciences Building Tyndall Avenue Bristol BS8 1TQ UK
| | - Andrew J Wilson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane Leeds LS2 9JT UK
- School of Chemistry, University of Leeds Woodhouse Lane Leeds LS2 9JT UK
| | - Thomas A Edwards
- Astbury Centre for Structural Molecular Biology, University of Leeds, Woodhouse Lane Leeds LS2 9JT UK
- School of Molecular and Cellular Biology, University of Leeds Woodhouse Lane Leeds LS2 9JT UK
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13
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Malagrinò F, Diop A, Pagano L, Nardella C, Toto A, Gianni S. Unveiling induced folding of intrinsically disordered proteins - Protein engineering, frustration and emerging themes. Curr Opin Struct Biol 2021; 72:153-160. [PMID: 34902817 DOI: 10.1016/j.sbi.2021.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/26/2021] [Accepted: 11/01/2021] [Indexed: 01/01/2023]
Abstract
Intrinsically disordered proteins (IDPs) can be generally described as a class of proteins that lack a well-defined ordered structure in isolation at physiological conditions. Upon binding to their physiological ligands, IDPs typically undergo a disorder-to-order transition, which may or may not lead to the complete folding of the IDP. In this short review, we focus on some of the key findings pertaining to the mechanisms of such induced folding. In particular, first we describe the general features of the reaction; then, we discuss some of the most remarkable findings obtained from applying protein engineering in synergy with kinetic studies to induced folding; and finally, we offer a critical view on some of the emerging themes when considering the structural heterogeneity of IDPs vis-à-vis to their inherent frustration.
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Affiliation(s)
- Francesca Malagrinò
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy
| | - Awa Diop
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy
| | - Livia Pagano
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy
| | - Caterina Nardella
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy
| | - Angelo Toto
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy.
| | - Stefano Gianni
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari Del CNR, Sapienza Università, di Roma, 00185, Rome, Italy.
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14
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Abstract
To predict transcription, one needs a mechanistic understanding of how the numerous required transcription factors (TFs) explore the nuclear space to find their target genes, assemble, cooperate, and compete with one another. Advances in fluorescence microscopy have made it possible to visualize real-time TF dynamics in living cells, leading to two intriguing observations: first, most TFs contact chromatin only transiently; and second, TFs can assemble into clusters through their intrinsically disordered regions. These findings suggest that highly dynamic events and spatially structured nuclear microenvironments might play key roles in transcription regulation that are not yet fully understood. The emerging model is that while some promoters directly convert TF-binding events into on/off cycles of transcription, many others apply complex regulatory layers that ultimately lead to diverse phenotypic outputs. Cracking this kinetic code is an ongoing and challenging task that is made possible by combining innovative imaging approaches with biophysical models.
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Affiliation(s)
- Feiyue Lu
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
| | - Timothée Lionnet
- Institute for Systems Genetics and Cell Biology Department, NYU School of Medicine, New York, New York 10016, USA
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15
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Theisen FF, Staby L, Tidemand FG, O'Shea C, Prestel A, Willemoës M, Kragelund BB, Skriver K. Quantification of Conformational Entropy Unravels Effect of Disordered Flanking Region in Coupled Folding and Binding. J Am Chem Soc 2021; 143:14540-14550. [PMID: 34473923 DOI: 10.1021/jacs.1c04214] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Intrinsic disorder (ID) constitutes a new dimension to the protein structure-function relationship. The ability to undergo conformational changes upon binding is a key property of intrinsically disordered proteins and remains challenging to study using conventional methods. A 1994 paper by R. S. Spolar and M. T. Record presented a thermodynamic approach for estimating changes in conformational entropy based on heat capacity changes, allowing quantification of residues folding upon binding. Here, we adapt the method for studies of intrinsically disordered proteins. We integrate additional data to provide a broader experimental foundation for the underlying relations and, based on >500 protein-protein complexes involving disordered proteins, reassess a key relation between polar and nonpolar surface area changes, previously determined using globular protein folding. We demonstrate the improved suitability of the adapted method to studies of the folded αα-hub domain RST from radical-induced cell death 1, whose interactome is characterized by ID. From extensive thermodynamic data, quantifying the conformational entropy changes upon binding, and comparison to the NMR structure, the adapted method improves accuracy for ID-based studies. Furthermore, we apply the method, in conjunction with NMR, to reveal hitherto undetected effects of interaction-motif context. Thus, inclusion of the disordered context of the DREB2A RST-binding motif induces structuring of the binding motif, resulting in major enthalpy-entropy compensation in the interaction interface. This study, also evaluating additional interactions, demonstrates the strength of the ID-adapted Spolar-Record thermodynamic approach for dissection of structural features of ID-based interactions, easily overlooked in traditional studies, and for translation of these into mechanistic knowledge.
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Affiliation(s)
| | | | - Frederik Grønbæk Tidemand
- Structural Biophysics, X-ray and Neutron Science, The Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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16
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Rodriguez-Rivera FP, Levi SM. Unifying Catalysis Framework to Dissect Proteasomal Degradation Paradigms. ACS CENTRAL SCIENCE 2021; 7:1117-1125. [PMID: 34345664 PMCID: PMC8323112 DOI: 10.1021/acscentsci.1c00389] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Indexed: 06/13/2023]
Abstract
Diverging from traditional target inhibition, proteasomal protein degradation approaches have emerged as novel therapeutic modalities that embody distinct pharmacological profiles and can access previously undrugged targets. Small molecule degraders have the potential to catalytically destroy target proteins at substoichiometric concentrations, thus lowering administered doses and extending pharmacological effects. With this mechanistic premise, research efforts have advanced the development of small molecule degraders that benefit from stable and increased affinity ternary complexes. However, a holistic framework that evaluates different degradation modes from a catalytic perspective, including focusing on kinetically favored degradation mechanisms, is lacking. In this Outlook, we introduce the concept of an induced cooperativity spectrum as a unifying framework to mechanistically understand catalytic degradation profiles. This framework is bolstered by key examples of published molecular degraders extending from molecular glues to bivalent degraders. Critically, we discuss remaining challenges and future opportunities in drug discovery to rationally design and phenotypically screen for efficient degraders.
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Affiliation(s)
- Frances P. Rodriguez-Rivera
- Discovery
Chemistry, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, New Jersey 07033, United States
| | - Samuel M. Levi
- Pfizer
Worldwide Research and Development, Pfizer,
Inc., 1 Portland Street, Cambridge, Massachusetts 02139, United States
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17
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Hofrova A, Lousa P, Kubickova M, Hritz J, Otasevic T, Repko M, Knight A, Piskacek M. Universal two-point interaction of mediator KIX with 9aaTAD activation domains. J Cell Biochem 2021; 122:1544-1555. [PMID: 34224597 DOI: 10.1002/jcb.30075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 01/05/2023]
Abstract
The nine-amino-acid activation domain (9aaTAD) is defined by a short amino acid pattern including two hydrophobic regions (positions p3-4 and p6-7). The KIX domain of mediator transcription CBP interacts with the 9aaTAD domains of transcription factors MLL, E2A, NF-kB, and p53. In this study, we analyzed the 9aaTADs-KIX interactions by nuclear magnetic resonance. The positions of three KIX helixes α1-α2-α3 are influenced by sterically-associated hydrophobic I611, L628, and I660 residues that are exposed to solvent. The positions of two rigid KIX helixes α1 and α2 generate conditions for structural folding in the flexible KIX-L12-G2 regions localized between them. The three KIX I611, L628, and I660 residues interact with two 9aaTAD hydrophobic residues in positions p3 and p4 and together build a hydrophobic core of five residues (5R). Numerous residues in 9aaTAD position p3 and p4 could provide this interaction. Following binding of the 9aaTAD to KIX, the hydrophobic I611, L628, and I660 residues are no longer exposed to solvent and their position changes inside the hydrophobic core together with position of KIX α1-α2-α3 helixes. The new positions of the KIX helixes α1 and α2 allow the KIX-L12-G2 enhanced formation. The second hydrophobic region of the 9aaTAD (positions p6 and p7) provides strong binding with the KIX-L12-G2 region. Similarly, multiple residues in 9aaTAD position p6 and p7 could provide this interaction. In conclusion, both 9aaTAD regions p3, p4 and p6, p7 provide co-operative and highly universal binding to mediator KIX. The hydrophobic core 5R formation allows new positions of the rigid KIX α-helixes and enables the enhanced formation of the KIX-L12-G2 region. This contributes to free energy and is the key for the KIX-9aaTAD binding. Therefore, the 9aaTAD-KIX interactions do not operate under the rigid key-and-lock mechanism what explains the 9aaTAD natural variability.
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Affiliation(s)
- Alena Hofrova
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.,National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Petr Lousa
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Monika Kubickova
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.,Core Facility Biomolecular Interactions and Crystallization (CF BIC), Masaryk University, Brno, Czech Republic
| | - Jozef Hritz
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.,Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tomas Otasevic
- Orthopaedic Clinic, University Hospital Brno and Faculty of Medicine Masaryk University Brno
| | - Martin Repko
- Orthopaedic Clinic, University Hospital Brno and Faculty of Medicine Masaryk University Brno
| | - Andrea Knight
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Martin Piskacek
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
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18
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Schier AC, Taatjes DJ. Everything at once: cryo-EM yields remarkable insights into human RNA polymerase II transcription. Nat Struct Mol Biol 2021; 28:540-543. [PMID: 34131334 PMCID: PMC10676001 DOI: 10.1038/s41594-021-00613-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
After years of only low-resolution and partial assemblies, the entire human pre-initiation complex (PIC), including the large and flexible Mediator and TFIID complexes, has come into focus. Five recent papers from three different research groups have transformed our understanding of transcription initiation by RNA polymerase II.
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Affiliation(s)
| | - Dylan J Taatjes
- Dept. of Biochemistry, University of Colorado, Boulder, CO, USA.
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19
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Garlick JM, Sturlis SM, Bruno PA, Yates JA, Peiffer AL, Liu Y, Goo L, Bao L, De Salle SN, Tamayo-Castillo G, Brooks CL, Merajver SD, Mapp AK. Norstictic Acid Is a Selective Allosteric Transcriptional Regulator. J Am Chem Soc 2021; 143:9297-9302. [PMID: 34137598 PMCID: PMC8717358 DOI: 10.1021/jacs.1c03258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Inhibitors of transcriptional protein-protein interactions (PPIs) have high value both as tools and for therapeutic applications. The PPI network mediated by the transcriptional coactivator Med25, for example, regulates stress-response and motility pathways, and dysregulation of the PPI networks contributes to oncogenesis and metastasis. The canonical transcription factor binding sites within Med25 are large (∼900 Å2) and have little topology, and thus, they do not present an array of attractive small-molecule binding sites for inhibitor discovery. Here we demonstrate that the depsidone natural product norstictic acid functions through an alternative binding site to block Med25-transcriptional activator PPIs in vitro and in cell culture. Norstictic acid targets a binding site comprising a highly dynamic loop flanking one canonical binding surface, and in doing so, it both orthosterically and allosterically alters Med25-driven transcription in a patient-derived model of triple-negative breast cancer. These results highlight the potential of Med25 as a therapeutic target as well as the inhibitor discovery opportunities presented by structurally dynamic loops within otherwise challenging proteins.
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Affiliation(s)
- Julie M Garlick
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Steven M Sturlis
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Paul A Bruno
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joel A Yates
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Amanda L Peiffer
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yejun Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Laura Goo
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - LiWei Bao
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Samantha N De Salle
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Charles L Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sofia D Merajver
- Department of Internal Medicine, Hematology/Oncology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Anna K Mapp
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
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20
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Henley MJ, Koehler AN. Advances in targeting 'undruggable' transcription factors with small molecules. Nat Rev Drug Discov 2021; 20:669-688. [PMID: 34006959 DOI: 10.1038/s41573-021-00199-0] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2021] [Indexed: 02/07/2023]
Abstract
Transcription factors (TFs) represent key biological players in diseases including cancer, autoimmunity, diabetes and cardiovascular disease. However, outside nuclear receptors, TFs have traditionally been considered 'undruggable' by small-molecule ligands due to significant structural disorder and lack of defined small-molecule binding pockets. Renewed interest in the field has been ignited by significant progress in chemical biology approaches to ligand discovery and optimization, especially the advent of targeted protein degradation approaches, along with increasing appreciation of the critical role a limited number of collaborators play in the regulation of key TF effector genes. Here, we review current understanding of TF-mediated gene regulation, discuss successful targeting strategies and highlight ongoing challenges and emerging approaches to address them.
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Affiliation(s)
- Matthew J Henley
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. .,The Broad Institute of MIT and Harvard, Cambridge, MA, USA. .,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Angela N Koehler
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. .,The Broad Institute of MIT and Harvard, Cambridge, MA, USA. .,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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21
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Mediator subunit Med15 dictates the conserved "fuzzy" binding mechanism of yeast transcription activators Gal4 and Gcn4. Nat Commun 2021; 12:2220. [PMID: 33850123 PMCID: PMC8044209 DOI: 10.1038/s41467-021-22441-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/11/2021] [Indexed: 02/05/2023] Open
Abstract
The acidic activation domain (AD) of yeast transcription factor Gal4 plays a dual role in transcription repression and activation through binding to Gal80 repressor and Mediator subunit Med15. The activation function of Gal4 arises from two hydrophobic regions within the 40-residue AD. We show by NMR that each AD region binds the Mediator subunit Med15 using a “fuzzy” protein interface. Remarkably, comparison of chemical shift perturbations shows that Gal4 and Gcn4, two intrinsically disordered ADs of different sequence, interact nearly identically with Med15. The finding that two ADs of different sequence use an identical fuzzy binding mechanism shows a common sequence-independent mechanism for AD-Mediator binding, similar to interactions within a hydrophobic cloud. In contrast, the same region of Gal4 AD interacts strongly with Gal80 via a distinct structured complex, implying that the structured binding partner of an intrinsically disordered protein dictates the type of protein–protein interaction. The intrinsically disordered acidic activation domain (AD) of the yeast transcription factor Gal4 acts through binding to the Med15 subunit of the Mediator complex. Here, the authors show that Gal4 interacts with Med15 through an identical fuzzy binding mechanism as Gcn4 AD, which has a different sequence, revealing a common sequence-independent mechanism for AD-Mediator binding. In contrast, Gal4 AD binds to the Gal80 repressor as a structured polypeptide, which strongly suggests that the structured binding partner dictates the type of protein–protein interaction for an intrinsically disordered protein.
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22
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Nussinov R, Jang H, Gursoy A, Keskin O, Gaponenko V. Inhibition of Nonfunctional Ras. Cell Chem Biol 2021; 28:121-133. [PMID: 33440168 PMCID: PMC7897307 DOI: 10.1016/j.chembiol.2020.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Intuitively, functional states should be targeted; not nonfunctional ones. So why could drugging the inactive K-Ras4BG12Cwork-but drugging the inactive kinase will likely not? The reason is the distinct oncogenic mechanisms. Kinase driver mutations work by stabilizing the active state and/or destabilizing the inactive state. Either way, oncogenic kinases are mostly in the active state. Ras driver mutations work by quelling its deactivation mechanisms, GTP hydrolysis, and nucleotide exchange. Covalent inhibitors that bind to the inactive GDP-bound K-Ras4BG12C conformation can thus work. By contrast, in kinases, allosteric inhibitors work by altering the active-site conformation to favor orthosteric drugs. From the translational standpoint this distinction is vital: it expedites effective pharmaceutical development and extends the drug classification based on the mechanism of action. Collectively, here we postulate that drug action relates to blocking the mechanism of activation, not to whether the protein is in the active or inactive state.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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23
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Bugge K, Staby L, Salladini E, Falbe-Hansen RG, Kragelund BB, Skriver K. αα-Hub domains and intrinsically disordered proteins: A decisive combo. J Biol Chem 2021; 296:100226. [PMID: 33361159 PMCID: PMC7948954 DOI: 10.1074/jbc.rev120.012928] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 01/02/2023] Open
Abstract
Hub proteins are central nodes in protein-protein interaction networks with critical importance to all living organisms. Recently, a new group of folded hub domains, the αα-hubs, was defined based on a shared αα-hairpin supersecondary structural foundation. The members PAH, RST, TAFH, NCBD, and HHD are found in large proteins such as Sin3, RCD1, TAF4, CBP, and harmonin, which organize disordered transcriptional regulators and membrane scaffolds in interactomes of importance to human diseases and plant quality. In this review, studies of structures, functions, and complexes across the αα-hubs are described and compared to provide a unified description of the group. This analysis expands the associated molecular concepts of "one domain-one binding site", motif-based ligand binding, and coupled folding and binding of intrinsically disordered ligands to additional concepts of importance to signal fidelity. These include context, motif reversibility, multivalency, complex heterogeneity, synergistic αα-hub:ligand folding, accessory binding sites, and supramodules. We propose that these multifaceted protein-protein interaction properties are made possible by the characteristics of the αα-hub fold, including supersite properties, dynamics, variable topologies, accessory helices, and malleability and abetted by adaptability of the disordered ligands. Critically, these features provide additional filters for specificity. With the presentations of new concepts, this review opens for new research questions addressing properties across the group, which are driven from concepts discovered in studies of the individual members. Combined, the members of the αα-hubs are ideal models for deconvoluting signal fidelity maintained by folded hubs and their interactions with intrinsically disordered ligands.
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Affiliation(s)
- Katrine Bugge
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Staby
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Edoardo Salladini
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus G Falbe-Hansen
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Karen Skriver
- REPIN and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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