scholarly journals Small molecule probes that perturb a protein–protein interface in antithrombin

2014 ◽  
Vol 5 (12) ◽  
pp. 4914-4921 ◽  
Author(s):  
Dongyue Xin ◽  
Andreas Holzenburg ◽  
Kevin Burgess
Keyword(s):  
Small Molecule ◽  
Protein Interactions ◽  
Protein Interface ◽  
Protein Protein Interactions ◽  
Target Proteins ◽  
Small Molecule Probes ◽  
Quaternary Structures

Small molecule probes for perturbing protein–protein interactions (PPIs) in vitro can be useful if they cause the target proteins to undergo biomedically relevant changes to their tertiary and quaternary structures.

scholarly journals Small molecules that inhibit TNF signalling by stabilising an asymmetric form of the trimer

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
James O’Connell ◽  
John Porter ◽  
Boris Kroeplien ◽  
Tim Norman ◽  
Stephen Rapecki ◽  
...  
Keyword(s):  
Small Molecules ◽  
Small Molecule ◽  
Protein Interactions ◽  
General Mechanism ◽  
Protein Protein Interactions ◽  
Biologic Drugs ◽  
Small Molecule Drugs ◽  
Necrosis Factor

AbstractTumour necrosis factor (TNF) is a cytokine belonging to a family of trimeric proteins; it has been shown to be a key mediator in autoimmune diseases such as rheumatoid arthritis and Crohn’s disease. While TNF is the target of several successful biologic drugs, attempts to design small molecule therapies directed to this cytokine have not led to approved products. Here we report the discovery of potent small molecule inhibitors of TNF that stabilise an asymmetrical form of the soluble TNF trimer, compromising signalling and inhibiting the functions of TNF in vitro and in vivo. This discovery paves the way for a class of small molecule drugs capable of modulating TNF function by stabilising a naturally sampled, receptor-incompetent conformation of TNF. Furthermore, this approach may prove to be a more general mechanism for inhibiting protein–protein interactions.

scholarly journals SET7/9-dependent methylation of ARTD1 at K508 stimulates poly-ADP-ribose formation after oxidative stress

Open Biology ◽  
2013 ◽  
Vol 3 (10) ◽  
pp. 120173 ◽  
Author(s):  
Ingrid Kassner ◽  
Anneli Andersson ◽  
Monika Fey ◽  
Martin Tomas ◽  
Elisa Ferrando-May ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protein Interactions ◽  
Protein Function ◽  
Dependent Manner ◽  
Protein Protein Interactions ◽  
Post Translational Modification ◽  
Target Proteins ◽  
Protein Methyltransferase

ADP-ribosyltransferase diphtheria toxin-like 1 (ARTD1, formerly PARP1) is localized in the nucleus, where it ADP-ribosylates specific target proteins. The post-translational modification (PTM) with a single ADP-ribose unit or with polymeric ADP-ribose (PAR) chains regulates protein function as well as protein–protein interactions and is implicated in many biological processes and diseases. SET7/9 (Setd7, KMT7) is a protein methyltransferase that catalyses lysine monomethylation of histones, but also methylates many non-histone target proteins such as p53 or DNMT1. Here, we identify ARTD1 as a new SET7/9 target protein that is methylated at K508 in vitro and in vivo . ARTD1 auto-modification inhibits its methylation by SET7/9, while auto-poly-ADP-ribosylation is not impaired by prior methylation of ARTD1. Moreover, ARTD1 methylation by SET7/9 enhances the synthesis of PAR upon oxidative stress in vivo . Furthermore, laser irradiation-induced PAR formation and ARTD1 recruitment to sites of DNA damage in a SET7/9-dependent manner. Together, these results reveal a novel mechanism for the regulation of cellular ARTD1 activity by SET7/9 to assure efficient PAR formation upon cellular stress.

scholarly journals Progress in the Discovery of Small-Molecule Inhibitors of Bromodomain–Histone Interactions

2011 ◽  
Vol 16 (10) ◽  
pp. 1170-1185 ◽  
Author(s):  
Chun-wa Chung ◽  
Jason Witherington
Keyword(s):  
Small Molecule ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Label Free ◽  
Protein Protein Interactions ◽  
Ligand Selectivity ◽  
Small Molecule Ligands ◽  
Associated Proteins ◽  
In Vitro Systems

Bromodomains are structurally conserved protein modules present in a large number of chromatin-associated proteins and in many nuclear histone acetyltransferases. The bromodomain functions as an acetyl-lysine binding domain and has been shown to be pivotal in regulating protein–protein interactions in chromatin-mediated cellular gene transcription, cell proliferation, and viral transcriptional activation. Structural analyses of these modules in complex with acetyl-lysine peptide ligands provide insights into the molecular basis for recognition and ligand selectivity within this epigenetic reader family. However, there are significant challenges in configuring assays to identify inhibitors of these proteins. This review focuses on the progress made in developing methods to identify peptidic and small-molecule ligands using biophysical label-free and biochemical approaches. The advantage of each technique and the results reported are summarized, highlighting the potential applicably to other reader domains and the caveats in translation from simple in vitro systems to a biological context.

Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

scholarly journals Identification and Biochemical Characterization of High Mobility Group Protein 20A as a Novel Ca2+/S100A6 Target

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 510
Author(s):  
Maho Yamamoto ◽  
Rina Kondo ◽  
Haruka Hozumi ◽  
Seita Doi ◽  
Miwako Denda ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Biochemical Characterization ◽  
S100 Protein ◽  
High Mobility ◽  
Dependent Manner ◽  
Protein Signaling ◽  
Protein Protein Interactions ◽  
High Mobility Group Protein ◽  
Pulldown Assay

During screening of protein-protein interactions, using human protein arrays carrying 19,676 recombinant glutathione s-transferase (GST)-fused human proteins, we identified the high-mobility protein group 20A (HMG20A) as a novel S100A6 binding partner. We confirmed the Ca2+-dependent interaction of HMG20A with S100A6 by the protein array method, biotinylated S100A6 overlay, and GST-pulldown assay in vitro and in transfected COS-7 cells. Co-immunoprecipitation of S100A6 with HMG20A from HeLa cells in a Ca2+-dependent manner revealed the physiological relevance of the S100A6/HMG20A interaction. In addition, HMG20A has the ability to interact with S100A1, S100A2, and S100B in a Ca2+-dependent manner, but not with S100A4, A11, A12, and calmodulin. S100A6 binding experiments using various HMG20A mutants revealed that Ca2+/S100A6 interacts with the C-terminal region (residues 311–342) of HMG20A with stoichiometric binding (HMG20A:S100A6 dimer = 1:1). This was confirmed by the fact that a GST-HMG20A mutant lacking the S100A6 binding region (residues 311–347, HMG20A-ΔC) failed to interact with endogenous S100A6 in transfected COS-7 cells, unlike wild-type HMG20A. Taken together, these results identify, for the first time, HMG20A as a target of Ca2+/S100 proteins, and may suggest a novel linkage between Ca2+/S100 protein signaling and HMG20A function, including in the regulation of neural differentiation.

scholarly journals Ways into Understanding HIF Inhibition

Cancers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 159
Author(s):  
Tina Schönberger ◽  
Joachim Fandrey ◽  
Katrin Prost-Fingerle
Keyword(s):  
Protein Interactions ◽  
Target Genes ◽  
Protein Protein Interactions ◽  
Low Oxygen ◽  
Drug Candidates ◽  
Open Questions ◽  
Wide Range ◽  
Hif Pathway

Hypoxia is a key characteristic of tumor tissue. Cancer cells adapt to low oxygen by activating hypoxia-inducible factors (HIFs), ensuring their survival and continued growth despite this hostile environment. Therefore, the inhibition of HIFs and their target genes is a promising and emerging field of cancer research. Several drug candidates target protein–protein interactions or transcription mechanisms of the HIF pathway in order to interfere with activation of this pathway, which is deregulated in a wide range of solid and liquid cancers. Although some inhibitors are already in clinical trials, open questions remain with respect to their modes of action. New imaging technologies using luminescent and fluorescent methods or nanobodies to complement widely used approaches such as chromatin immunoprecipitation may help to answer some of these questions. In this review, we aim to summarize current inhibitor classes targeting the HIF pathway and to provide an overview of in vitro and in vivo techniques that could improve the understanding of inhibitor mechanisms. Unravelling the distinct principles regarding how inhibitors work is an indispensable step for efficient clinical applications and safety of anticancer compounds.

scholarly journals EEF1A2 interacts with HSP90AB1 to promote lung adenocarcinoma metastasis via enhancing TGF-β/SMAD signalling

2021 ◽  
Author(s):  
Liqing Jia ◽  
Xiaolu Ge ◽  
Chao Du ◽  
Linna Chen ◽  
Yanhong Zhou ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Protein Interactions ◽  
Elongation Factor ◽  
Protein Translation ◽  
Protein Protein Interactions ◽  
Promising Target ◽  
Tgfβ Receptor ◽  
Mesenchymal Transformation

Abstract Background Eukaryotic protein translation elongation factor 1α2 (EEF1A2) is an oncogene that promotes the progression of breast and pancreatic cancer. In this study, we aimed to elucidate the oncogenic function of EEF1A2 in the metastasis of lung adenocarcinoma (LUAD). Methods Immunohistochemistry and western blot were used to study EEF1A2 expression levels in LUAD tissues and cells, respectively. The role of EEF1A2 in LUAD progression were investigated in vitro and in vivo. We identified potential EEF1A2-binding proteins by liquid chromatography-electrospray mass spectrometry (LC-MS)/MS. Protein–protein interactions were determined by immunofluorescence and co-immunoprecipitation (Co-IP). Results In this study, we report that EEF1A2 mediates the epithelial–mesenchymal transformation (EMT), to promote the metastasis of LUAD cells in vitro and in vivo. Moreover, EEF1A2 interacts with HSP90AB1 to increase TGFβ Receptor (TβR)-I, and TβRII expression, followed by enhanced SMAD3 and pSMAD3 expression and nuclear localisation, which promotes the EMT of LUAD cells. Overexpression of EEF1A2 in cancer tissues is associated with poor prognosis and short survival of patients with LUAD. Conclusions These findings underscore the molecular functions of EEF1A2 in LUAD metastasis and indicate that EEF1A2 represents a promising target in the treatment of aggressive LUAD.

c-Fos-induced activation of a TATA-box-containing promoter involves direct contact with TATA-box-binding protein

1994 ◽  
Vol 14 (9) ◽  
pp. 6021-6029
Author(s):  
R Metz ◽  
A J Bannister ◽  
J A Sutherland ◽  
C Hagemeier ◽  
E C O'Rourke ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Tata Box ◽  
Binding Motif ◽  
Protein Protein Interactions ◽  
High Concentrations ◽  
Tata Box Binding Protein

Transcriptional activation in eukaryotes involves protein-protein interactions between regulatory transcription factors and components of the basal transcription machinery. Here we show that c-Fos, but not a related protein, Fra-1, can bind the TATA-box-binding protein (TBP) both in vitro and in vivo and that c-Fos can also interact with the transcription factor IID complex. High-affinity binding to TBP requires c-Fos activation modules which cooperate to activate transcription. One of these activation modules contains a TBP-binding motif (TBM) which was identified through its homology to TBP-binding viral activators. This motif is required for transcriptional activation, as well as TBP binding. Domain swap experiments indicate that a domain containing the TBM can confer TBP binding on Fra-1 both in vitro and in vivo. In vivo activation experiments indicate that a GAL4-Fos fusion can activate a promoter bearing a GAL4 site linked to a TATA box but that this activity does not occur at high concentrations of GAL4-Fos. This inhibition (squelching) of c-Fos activity is relieved by the presence of excess TBP, indicating that TBP is a direct functional target of c-Fos. Removing the TBM from c-Fos severely abrogates activation of a promoter containing a TATA box but does not affect activation of a promoter driven only by an initiator element. Collectively, these results suggest that c-Fos is able to activate via two distinct mechanisms, only one of which requires contact with TBP. Since TBP binding is not exhibited by Fra-1, TBP-mediated activation may be one characteristic that discriminates the function of Fos-related proteins.

Elucidating Protein-protein Interactions Through Computational Approaches and Designing Small Molecule Inhibitors Against them for Various Diseases

2018 ◽  
Vol 18 (20) ◽  
pp. 1719-1736 ◽  
Author(s):  
Sharanya Sarkar ◽  
Khushboo Gulati ◽  
Manikyaprabhu Kairamkonda ◽  
Amit Mishra ◽  
Krishna Mohan Poluri
Keyword(s):  
Small Molecule ◽  
Protein Interactions ◽  
Small Molecule Inhibitors ◽  
Computational Techniques ◽  
Protein Protein Interactions ◽  
Computational Tools ◽  
Computational Approaches ◽  
Protein Protein Interaction ◽  
Wide Range ◽  
Therapeutic Measures

Background: To carry out wide range of cellular functionalities, proteins often associate with one or more proteins in a phenomenon known as Protein-Protein Interaction (PPI). Experimental and computational approaches were applied on PPIs in order to determine the interacting partners, and also to understand how an abnormality in such interactions can become the principle cause of a disease. Objective: This review aims to elucidate the case studies where PPIs involved in various human diseases have been proven or validated with computational techniques, and also to elucidate how small molecule inhibitors of PPIs have been designed computationally to act as effective therapeutic measures against certain diseases. Results: Computational techniques to predict PPIs are emerging rapidly in the modern day. They not only help in predicting new PPIs, but also generate outputs that substantiate the experimentally determined results. Moreover, computation has aided in the designing of novel inhibitor molecules disrupting the PPIs. Some of them are already being tested in the clinical trials. Conclusion: This review delineated the classification of computational tools that are essential to investigate PPIs. Furthermore, the review shed light on how indispensable computational tools have become in the field of medicine to analyze the interaction networks and to design novel inhibitors efficiently against dreadful diseases in a shorter time span.

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