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Salgania HK, Metz J, Jeske M. ReLo is a simple and rapid colocalization assay to identify and characterize direct protein-protein interactions. Nat Commun 2024; 15:2875. [PMID: 38570497 PMCID: PMC10991417 DOI: 10.1038/s41467-024-47233-4] [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: 03/12/2022] [Accepted: 03/22/2024] [Indexed: 04/05/2024] Open
Abstract
The characterization of protein-protein interactions (PPIs) is fundamental to the understanding of biochemical processes. Many methods have been established to identify and study direct PPIs; however, screening and investigating PPIs involving large or poorly soluble proteins remains challenging. Here, we introduce ReLo, a simple, rapid, and versatile cell culture-based method for detecting and investigating interactions in a cellular context. Our experiments demonstrate that ReLo specifically detects direct binary PPIs. Furthermore, we show that ReLo bridging experiments can also be used to determine the binding topology of subunits within multiprotein complexes. In addition, ReLo facilitates the identification of protein domains that mediate complex formation, allows screening for interfering point mutations, and it is sensitive to drugs that mediate or disrupt an interaction. In summary, ReLo is a simple and rapid alternative for the study of PPIs, especially when studying structurally complex proteins or when established methods fail.
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Affiliation(s)
- Harpreet Kaur Salgania
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Jutta Metz
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Mandy Jeske
- Heidelberg University Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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Begitt A, Krause S, Cavey JR, Vinkemeier DE, Vinkemeier U. A family-wide assessment of latent STAT transcription factor interactions reveals divergent dimer repertoires. J Biol Chem 2023; 299:104703. [PMID: 37059181 DOI: 10.1016/j.jbc.2023.104703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/16/2023] Open
Abstract
The conversion of STAT proteins from latent to active transcription factors is central to cytokine signalling. Triggered by their signal-induced tyrosine phosphorylation, it is the assembly of a range of cytokine-specific STAT homo- and heterodimers that marks a key step in the transition of hitherto latent proteins to transcription activators. In contrast, the constitutive self-assembly of latent STATs and how it relates to the functioning of activated STATs, is understood less well. To provide a more complete picture, we developed a co-localization-based assay and tested all 28 possible combinations of the seven unphosphorylated STAT (U-STAT) proteins in living cells. We identified five U-STAT homodimers -STAT1, STAT3, STAT4, STAT5A and STAT5B- and two heterodimers -STAT1:STAT2 and STAT5A:STAT5B- and performed semi-quantitative assessments of the forces and characterizations of binding interfaces that support them. One STAT protein -STAT6- was found to be monomeric. This comprehensive analysis of latent STAT self-assembly lays bare considerable structural and functional diversity in the ways that link STAT dimerization before and after activation.
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Affiliation(s)
- Andreas Begitt
- The University of Nottingham, School of Life Sciences, Nottingham, UK
| | - Sebastian Krause
- The University of Nottingham, School of Life Sciences, Nottingham, UK
| | - James R Cavey
- The University of Nottingham, School of Life Sciences, Nottingham, UK
| | | | - Uwe Vinkemeier
- The University of Nottingham, School of Life Sciences, Nottingham, UK
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Winkler J, Mylle E, De Meyer A, Pavie B, Merchie J, Grones P, Van Damme D. Visualizing protein-protein interactions in plants by rapamycin-dependent delocalization. THE PLANT CELL 2021; 33:1101-1117. [PMID: 33793859 PMCID: PMC7612334 DOI: 10.1093/plcell/koab004] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/15/2020] [Indexed: 05/19/2023]
Abstract
Identifying protein-protein interactions (PPIs) is crucial for understanding biological processes. Many PPI tools are available, yet only some function within the context of a plant cell. Narrowing down even further, only a few tools allow complex multi-protein interactions to be visualized. Here, we present a conditional in vivo PPI tool for plant research that meets these criteria. Knocksideways in plants (KSP) is based on the ability of rapamycin to alter the localization of a bait protein and its interactors via the heterodimerization of FKBP and FRB domains. KSP is inherently free from many limitations of other PPI systems. This in vivo tool does not require spatial proximity of the bait and prey fluorophores and it is compatible with a broad range of fluorophores. KSP is also a conditional tool and therefore the visualization of the proteins in the absence of rapamycin acts as an internal control. We used KSP to confirm previously identified interactions in Nicotiana benthamiana leaf epidermal cells. Furthermore, the scripts that we generated allow the interactions to be quantified at high throughput. Finally, we demonstrate that KSP can easily be used to visualize complex multi-protein interactions. KSP is therefore a versatile tool with unique characteristics and applications that complements other plant PPI methods.
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Affiliation(s)
- Joanna Winkler
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Evelien Mylle
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Andreas De Meyer
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | | | - Julie Merchie
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Peter Grones
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Daniёl Van Damme
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
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Yurlova L, Derks M, Buchfellner A, Hickson I, Janssen M, Morrison D, Stansfield I, Brown CJ, Ghadessy FJ, Lane DP, Rothbauer U, Zolghadr K, Krausz E. The fluorescent two-hybrid assay to screen for protein-protein interaction inhibitors in live cells: targeting the interaction of p53 with Mdm2 and Mdm4. ACTA ACUST UNITED AC 2014; 19:516-25. [PMID: 24476585 DOI: 10.1177/1087057113518067] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Protein-protein interactions (PPIs) are attractive but challenging targets for drug discovery. To overcome numerous limitations of the currently available cell-based PPI assays, we have recently established a fully reversible microscopy-assisted fluorescent two-hybrid (F2H) assay. The F2H assay offers a fast and straightforward readout: an interaction-dependent co-localization of two distinguishable fluorescent signals at a defined spot in the nucleus of mammalian cells. We developed two reversible F2H assays for the interactions between the tumor suppressor p53 and its negative regulators, Mdm2 and Mdm4. We then performed a pilot F2H screen with a subset of compounds, including small molecules (such as Nutlin-3) and stapled peptides. We identified five cell-penetrating compounds as potent p53-Mdm2 inhibitors. However, none exhibited intracellular activity on p53-Mdm4. Live cell data generated by the F2H assays enable the characterization of stapled peptides based on their ability to penetrate cells and disrupt p53-Mdm2 interaction as well as p53-Mdm4 interaction. Here, we show that the F2H assays enable side-by-side analysis of substances' dual Mdm2-Mdm4 activity. In addition, they are suitable for testing various types of compounds (e.g., small molecules and peptidic inhibitors) and concurrently provide initial data on cellular toxicity. Furthermore, F2H assays readily allow real-time visualization of PPI dynamics in living cells.
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Davis JR, Mossalam M, Lim CS. Controlled access of p53 to the nucleus regulates its proteasomal degradation by MDM2. Mol Pharm 2013; 10:1340-9. [PMID: 23398638 DOI: 10.1021/mp300543t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The tumor suppressor p53 can be sent to the proteasome for degradation by placing its nucleo-cytoplasmic shuttling under ligand control. Endogenous p53 is ubiquitinated by MDM2 in the nucleus, and controlling the access of p53 to the nuclear compartment regulates its ubiquitination and proteasomal degradation. This was accomplished by the use of a protein switch that places nuclear translocation under the control of externally applied dexamethasone. Fluorescence microscopy revealed that sending protein switch p53 (PS-p53) to the nucleus produces a distinct punctate distribution in both the cytoplasm and nucleus. The nuclear role in accessing the proteasome was investigated by inhibiting classical nuclear export with leptomycin B. Trapping PS-p53 in the nucleus only allows this punctate staining in that compartment, suggesting that PS-p53 must translocate first to the nuclear compartment for cytoplasmic punctate staining to occur. The role of MDM2 binding was explored by inhibiting MDM2/p53 binding with nutlin-3. Inhibition of this interaction blocked both nuclear export and cytoplasmic and nuclear punctate staining, providing evidence that any change in localization after nuclear translocation is due to MDM2 binding. Further, blocking the proteolytic activity of the proteasome maintained the nuclear localization of the construct. Truncations of p53 were made to determine smaller constructs still capable of interacting with MDM2, and their subcellular localization and degradation potential was observed. PS-p53 and a smaller construct containing the two MDM2 binding regions of p53 (Box I + V) were indeed degraded by the proteasome as measured by loss of enhanced green fluorescent protein that was also fused to the construct. The influence of these constructs on p53 gene transactivation function was assessed and revealed that PS-p53 decreased gene transactivation, while PS-p53(Box I + V) did not significantly change baseline gene transactivation.
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Affiliation(s)
- James R Davis
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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Diversity in genetic in vivo methods for protein-protein interaction studies: from the yeast two-hybrid system to the mammalian split-luciferase system. Microbiol Mol Biol Rev 2012; 76:331-82. [PMID: 22688816 DOI: 10.1128/mmbr.05021-11] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The yeast two-hybrid system pioneered the field of in vivo protein-protein interaction methods and undisputedly gave rise to a palette of ingenious techniques that are constantly pushing further the limits of the original method. Sensitivity and selectivity have improved because of various technical tricks and experimental designs. Here we present an exhaustive overview of the genetic approaches available to study in vivo binary protein interactions, based on two-hybrid and protein fragment complementation assays. These methods have been engineered and employed successfully in microorganisms such as Saccharomyces cerevisiae and Escherichia coli, but also in higher eukaryotes. From single binary pairwise interactions to whole-genome interactome mapping, the self-reassembly concept has been employed widely. Innovative studies report the use of proteins such as ubiquitin, dihydrofolate reductase, and adenylate cyclase as reconstituted reporters. Protein fragment complementation assays have extended the possibilities in protein-protein interaction studies, with technologies that enable spatial and temporal analyses of protein complexes. In addition, one-hybrid and three-hybrid systems have broadened the types of interactions that can be studied and the findings that can be obtained. Applications of these technologies are discussed, together with the advantages and limitations of the available assays.
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Davis JR, Mossalam M, Lim CS. Utilizing the estrogen receptor ligand-binding domain for controlled protein translocation to the insoluble fraction. Pharm Res 2012; 29:3455-63. [PMID: 22869106 DOI: 10.1007/s11095-012-0840-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 07/16/2012] [Indexed: 01/23/2023]
Abstract
PURPOSE The estrogen receptor forms insoluble aggregates in the insoluble cytoskeletal subcellular fraction when bound to the antagonist fulvestrant. The ligand-binding domain was isolated and fused to signal sequences to target subcellular compartments. Sequestering a pro-apoptotic peptide tested the utility of a protein targeted to the insoluble fraction. METHODS The ligand-binding domain of the estrogen receptor was isolated and fused with signal sequences, either a nuclear localization signal or nuclear export signal. The subcellular localization when bound to drug fulvestrant was examined, specifically its interaction with cytokeratins 8 and 18. The ability to target a therapeutic peptide to the insoluble fraction was tested by fusing a therapeutic coiled-coil from Bcr-Abl in K562 cells. RESULTS The estrogen receptor ligand-binding domain responds to fulvestrant by translocating to the insoluble fraction. Adding a signal sequence significantly limited the translocation to either the nucleus or cytoplasm. The cytokeratin 8/18 status of the cell did not alter this response. The therapeutic coiled-coil fused to ERLBD was inactivated upon ligand induction. CONCLUSIONS Isolating the ligand-binding domain of the estrogen receptor creates a ligand-controllable protein capable of translocation to the insoluble fraction. This can be used to sequester an active peptide to alter its function.
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Affiliation(s)
- James R Davis
- Department of Pharmaceutics and Pharmaceutical Chemistry College of Pharmacy, University of Utah, Salt Lake City, Utah, USA.
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Cubeddu L, Joseph S, Richard DJ, Matthews JM. Contribution of DEAF1 structural domains to the interaction with the breast cancer oncogene LMO4. PLoS One 2012; 7:e39218. [PMID: 22723967 PMCID: PMC3378519 DOI: 10.1371/journal.pone.0039218] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 05/17/2012] [Indexed: 12/22/2022] Open
Abstract
The proteins LMO4 and DEAF1 contribute to the proliferation of mammary epithelial cells. During breast cancer LMO4 is upregulated, affecting its interaction with other protein partners. This may set cells on a path to tumour formation. LMO4 and DEAF1 interact, but it is unknown how they cooperate to regulate cell proliferation. In this study, we identify a specific LMO4-binding domain in DEAF1. This domain contains an unstructured region that directly contacts LMO4, and a coiled coil that contains the DEAF1 nuclear export signal (NES). The coiled coil region can form tetramers and has the typical properties of a coiled coil domain. Using a simple cell-based assay, we show that LMO4 modulates the activity of the DEAF NES, causing nuclear accumulation of a construct containing the LMO4-interaction region of DEAF1.
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Affiliation(s)
- Liza Cubeddu
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (LC); (JM)
| | - Soumya Joseph
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, Australia
| | - Derek J. Richard
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Jacqueline M. Matthews
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (LC); (JM)
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Dixon AS, Constance JE, Tanaka T, Rabbitts TH, Lim CS. Changing the subcellular location of the oncoprotein Bcr-Abl using rationally designed capture motifs. Pharm Res 2011; 29:1098-109. [PMID: 22183511 DOI: 10.1007/s11095-011-0654-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/06/2011] [Indexed: 11/30/2022]
Abstract
PURPOSE Bcr-Abl, the causative agent of chronic myelogenous leukemia (CML), localizes in the cytoplasm where its oncogenic signaling leads to proliferation of cells. If forced into the nucleus Bcr-Abl causes apoptosis. To achieve nuclear translocation, binding domains for capture of Bcr-Abl were generated and attached to proteins with signals destined for the nucleus. These resulting proteins would be capable of binding and translocating endogenous Bcr-Abl to the nucleus. METHODS Bcr-Abl was targeted at 3 distinct domains for capture: by construction of high affinity intracellular antibody domains (iDabs) to regions of Bcr-Abl known to promote cytoplasmic retention, via its coiled coil domain (CC), and through a naturally occurring protein-protein interaction domain (RIN1). These binding domains were then tested for their ability to escort Bcr-Abl into the nucleus using a "protein switch" or attachment of 4 nuclear localization signals (NLSs). RESULTS Although RIN1, ABI7-iDab, and CCmut3 constructs all produced similar colocalization with Bcr-Abl, only 4NLS-CCmut3 produced efficient nuclear translocation of Bcr-Abl. CONCLUSIONS We demonstrate that a small binding domain can be used to control the subcellular localization of Bcr-Abl, which may have implications for CML therapy. Our ultimate future goal is to change the location of critical proteins to alter their function.
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Affiliation(s)
- Andrew S Dixon
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, 421 Wakara Way, Rm. 318, Salt Lake City, Utah 84108, USA
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Dixon AS, Pendley SS, Bruno BJ, Woessner DW, Shimpi AA, Cheatham TE, Lim CS. Disruption of Bcr-Abl coiled coil oligomerization by design. J Biol Chem 2011; 286:27751-60. [PMID: 21659527 DOI: 10.1074/jbc.m111.264903] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Oligomerization is an important regulatory mechanism for many proteins, including oncoproteins and other pathogenic proteins. The oncoprotein Bcr-Abl relies on oligomerization via its coiled coil domain for its kinase activity, suggesting that a designed coiled coil domain with enhanced binding to Bcr-Abl and reduced self-oligomerization would be therapeutically useful. Key mutations in the coiled coil domain of Bcr-Abl were identified that reduce homo-oligomerization through intermolecular charge-charge repulsion yet increase interaction with the Bcr-Abl coiled coil through additional salt bridges, resulting in an enhanced ability to disrupt the oligomeric state of Bcr-Abl. The mutations were modeled computationally to optimize the design. Assays performed in vitro confirmed the validity and functionality of the optimal mutations, which were found to exhibit reduced homo-oligomerization and increased binding to the Bcr-Abl coiled coil domain. Introduction of the mutant coiled coil into K562 cells resulted in decreased phosphorylation of Bcr-Abl, reduced cell proliferation, and increased caspase-3/7 activity and DNA segmentation. Importantly, the mutant coiled coil domain was more efficacious than the wild type in all experiments performed. The improved inhibition of Bcr-Abl through oligomeric disruption resulting from this modified coiled coil domain represents a viable alternative to small molecule inhibitors for therapeutic intervention.
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Affiliation(s)
- Andrew S Dixon
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA
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