Multivalent Ligands with Tailor‐Made Anion Binding Motif as Stabilizers of Protein–Protein Interactions

ChemBioChem ◽  
2019 ◽  
Vol 20 (23) ◽  
pp. 2921-2926 ◽  
Author(s):  
Lina Bartsch ◽  
Maria Bartel ◽  
Alba Gigante ◽  
Javier Iglesias‐Fernández ◽  
Yasser B. Ruiz‐Blanco ◽  
...  
1994 ◽  
Vol 14 (9) ◽  
pp. 6021-6029
Author(s):  
R Metz ◽  
A J Bannister ◽  
J A Sutherland ◽  
C Hagemeier ◽  
E C O'Rourke ◽  
...  

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Su-Fang Wang ◽  
Sangho Oh ◽  
Yue-Xiu Si ◽  
Zhi-Jiang Wang ◽  
Hong-Yan Han ◽  
...  

The various studies on tyrosinase have recently gained the attention of researchers due to their potential application values and the biological functions. In this study, we predicted the 3D structure of human tyrosinase and simulated the protein-protein interactions between tyrosinase and three binding partners, four and half LIM domains 2 (FHL2), cytochrome b-245 alpha polypeptide (CYBA), and RNA-binding motif protein 9 (RBM9). Our interaction simulations showed significant binding energy scores of −595.3 kcal/mol for FHL2, −859.1 kcal/mol for CYBA, and −821.3 kcal/mol for RBM9. We also investigated the residues of each protein facing toward the predicted site of interaction with tyrosinase. Our computational predictions will be useful for elucidating the protein-protein interactions of tyrosinase and studying its binding mechanisms.


2020 ◽  
Vol 295 (14) ◽  
pp. 4464-4476
Author(s):  
Eleanor R. Martin ◽  
Alessandro Barbieri ◽  
Robert C. Ford ◽  
Robert C. Robinson

Crystallization of recombinant proteins has been fundamental to our understanding of protein function, dysfunction, and molecular recognition. However, this information has often been gleaned under extremely nonphysiological protein, salt, and H+ concentrations. Here, we describe the development of a robust Inka1-Box (iBox)–PAK4cat system that spontaneously crystallizes in several mammalian cell types. The semi-quantitative assay described here allows the measurement of in vivo protein-protein interactions using a novel GFP-linked reporter system that produces fluorescent readouts from protein crystals. We combined this assay with in vitro X-ray crystallography and molecular dynamics studies to characterize the molecular determinants of the interaction between the PDZ2 domain of Na+/H+ exchange regulatory cofactor NHE-RF1 (NHERF1) and cystic fibrosis transmembrane conductance regulator (CFTR), a protein complex pertinent to the genetic disease cystic fibrosis. These experiments revealed the crystal structure of the extended PDZ domain of NHERF1 and indicated, contrary to what has been previously reported, that residue selection at positions −1 and −3 of the PDZ-binding motif influences the affinity and specificity of the NHERF1 PDZ2-CFTR interaction. Our results suggest that this system could be utilized to screen additional protein-protein interactions, provided they can be accommodated within the spacious iBox-PAK4cat lattice.


2019 ◽  
Author(s):  
Eleanor R. Martin ◽  
Alessandro Barbieri ◽  
Robert C. Ford ◽  
Robert C. Robinson

AbstractCrystallisation of recombinant proteins has been fundamental to our understanding of protein function, dysfunction, and molecular recognition. However, this information has often been gleaned under non-physiological extremes of protein, salt, and H+ concentrations. Here, we describe the development of the robust iBox-PAK4cat system that spontaneously crystallises in several mammalian cell types. The developments described here allow the quantitation of in-vivo protein-protein interactions using a novel GFP-linked reporter system. Here, we have combined this assay with in-vitro X-ray crystallography and molecular dynamics studies characterise the molecular determinants of the interaction between NHERF1 PDZ2 and CFTR, a protein complex pertinent to the genetic disease cystic fibrosis. These studies have revealed the crystal structure of the extended PDZ domain of NHERF1, and indicated, contrary to previous reports, that residue selection at −1 and −3 PDZ-binding motif positions influence the affinity and specificity of the interaction. The results presented here demonstrate that the iBox-PAK4cat assay could easily be utilised to screen other protein-protein interactions.


2019 ◽  
Author(s):  
Erik Czipa ◽  
Mátyás Schiller ◽  
Tibor Nagy ◽  
Levente Kontra ◽  
László Steiner ◽  
...  

ABSTRACTChIP-Seq reveals genomic regions where proteins, e.g. transcription factors (TFs) interact with DNA. A substantial fraction of these regions, however, do not contain the cognate binding site for the TF of interest. This phenomenon might be explained by protein-protein interactions and co-precipitation of interacting gene regulatory elements. We uniformly processed 3,727 human ChIP-Seq data sets and determined the cistrome of 292 TFs, as well as the distances between the TF binding motif centers and the ChIP-Seq peak summits.ChIPSummitDB enables the analysis of ChIP-Seq data using multiple approaches. The 292 cistromes and corresponding ChIP-Seq peak sets can be browsed in GenomeView. Overlapping SNPs can be inspected in dbSNPView. Most importantly, the MotifView and PairShiftView pages show the average distance between motif centers and overlapping ChIP-Seq peak summits and distance distributions thereof, respectively.In addition to providing a comprehensive human TF binding site collection, the ChIPSummitDB database and web interface allows for the examination of the topological arrangement of TF complexes genome-wide. ChIPSummitDB is freely accessible at http://summit.med.unideb.hu/summitdb/. The database will be regularly updated and extended with the newly available human and mouse ChIP-Seq data sets.


2020 ◽  
Author(s):  
Melody Gao ◽  
Iain G. P. Mackley ◽  
Samaneh Mesbahi-Vasey ◽  
Haley A. Bamonte ◽  
Sarah A. Struyvenberg ◽  
...  

AbstractThe evolution of signaling pathways is complex and well-studied. In particular, the emergence of animal multicellularity had a major impact on protein-protein interactions and signaling systems in eukaryotic cells. However, choanoflagellates, our closest non-metazoan ancestor, contain a number of closely related signaling and trafficking proteins and domains. In addition, because choanoflagellates can adopt a rosette-/multicellular-like state, a lot can be gained by comparing proteins involved in choanoflagellate and human signaling pathways. Here, we look at how selectivity determinants evolved in the PDZ domain. There are over 250 PDZ domains in the human proteome, which are involved in critical protein-protein interactions that result in large multimolecular complexes, e.g., in the postsynaptic density of neuronal synapses. Binding of C-terminal sequences by PDZ domains is often transient and recognition typically involves 6 residues or less, with only 2 residues specifying the binding motif. We solved high resolution crystal structures of Monosiga brevicollis PDZ domains homologous to human Dlg1 PDZ2, Dlg1 PDZ3, GIPC, and SHANK1 PDZ domains to investigate if the non-motif preferences are conserved, despite hundreds of millions of years of evolution. We also calculated binding affinities for GIPC, SHANK1, and SNX27 PDZ domains from M. brevicollis. Overall, we found that peptide selectivity is conserved between these two disparate organisms, with one exception, mbDLG-3. In addition, we identify 178 PDZ domains in the M. brevicollis proteome, including 11 new sequences, which we verified using Rosetta and homology modeling. Overall, our results provide novel insight into signaling pathways in the choanoflagellate organism.


Database ◽  
2020 ◽  
Vol 2020 ◽  
Author(s):  
Erik Czipa ◽  
Mátyás Schiller ◽  
Tibor Nagy ◽  
Levente Kontra ◽  
László Steiner ◽  
...  

Abstract ChIP-seq reveals genomic regions where proteins, e.g. transcription factors (TFs) interact with DNA. A substantial fraction of these regions, however, do not contain the cognate binding site for the TF of interest. This phenomenon might be explained by protein–protein interactions and co-precipitation of interacting gene regulatory elements. We uniformly processed 3727 human ChIP-seq data sets and determined the cistrome of 292 TFs, as well as the distances between the TF binding motif centers and the ChIP-seq peak summits. ChIPSummitDB enables the analysis of ChIP-seq data using multiple approaches. The 292 cistromes and corresponding ChIP-seq peak sets can be browsed in GenomeView. Overlapping SNPs can be inspected in dbSNPView. Most importantly, the MotifView and PairShiftView pages show the average distance between motif centers and overlapping ChIP-seq peak summits and distance distributions thereof, respectively. In addition to providing a comprehensive human TF binding site collection, the ChIPSummitDB database and web interface allows for the examination of the topological arrangement of TF complexes genome-wide. ChIPSummitDB is freely accessible at http://summit.med.unideb.hu/summitdb/. The database will be regularly updated and extended with the newly available human and mouse ChIP-seq data sets.


1994 ◽  
Vol 14 (9) ◽  
pp. 6021-6029 ◽  
Author(s):  
R Metz ◽  
A J Bannister ◽  
J A Sutherland ◽  
C Hagemeier ◽  
E C O'Rourke ◽  
...  

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.


2014 ◽  
Vol 463 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Elsa Franco-Echevarría ◽  
Jose I. Baños-Sanz ◽  
Begoña Monterroso ◽  
Adam Round ◽  
Julia Sanz-Aparicio ◽  
...  

Inositol 1,4,5-trisphosphate 3-kinase regulation by Ca2+/calmodulin involves multiple protein–protein interactions, which form a highly hydrophobic interface and defines a new calmodulin-binding motif. The structural data support that calmodulin binds to an autoinhibitory segment facilitating the kinase activity.


2018 ◽  
Author(s):  
Fang Bai ◽  
Jacob Corll ◽  
Donya N. Shodja ◽  
Ruth Davenport ◽  
Guanqiao Feng ◽  
...  

AbstractThe last eukaryotic common ancestor had two classes of introns that are still found in most eukaryotic lineages. Common U2-type and rare U12-type introns are spliced by the major and minor spliceosomes, respectively. Relatively few splicing factors have been shown to be specific to the minor spliceosome. We found that the maize RNA Binding Motif Protein48 (RBM48) is a U12 splicing factor that functions to promote cell differentiation and repress cell proliferation. RBM48 is coselected with the U12 splicing factor, ZRSR2/RGH3. Protein-protein interactions between RBM48, RGH3, and U2 Auxiliary Factor (U2AF) subunits suggest major and minor spliceosome factors may form complexes during intron recognition. Human RBM48 interacts with ARMC7. Maize RBM48 and ARMC7 have a conserved protein-protein interaction. These data predict that RBM48 is likely to function in U12 splicing throughout eukaryotes and that U12 splicing promotes endosperm cell differentiation in maize.


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