Affinity capture of polyribosomes followed by RNAseq (ACAPseq), a discovery platform for protein-protein interactions
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PROVIDER: PRJNA497571 | ENA |
REPOSITORIES: ENA
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Project description:Defining protein-protein interactions (PPIs) is central to the biological sciences. Here, we present a novel platform - Affinity Capture of Polyribosomes followed by RNA sequencing (ACAPseq) - for identifying PPIs. ACAPseq harnesses the power of massively parallel RNA sequencing (RNAseq) to quantify the enrichment of polyribosomes based on the affinity of their associated nascent polypeptides for an immobilized protein “bait”. This method was developed and tested using neonatal mouse brain polyribosomes and a variety of extracellular domains as baits. Of 92 baits tested, 25 identified one or more binding partners that appear to be biologically relevant; additional candidate partners remain to be validated. ACAPseq can detect binding to targets that are present at less than 1 part in 100,000 in the starting polyribosome preparation. One of the observed PPIs wes analyzed in detail, revealing the mode of homophilic binding for Protocadherin-9 (PCDH9), a non-clustered Protocadherin family member.
2018-10-20 | GSE121524 | GEO
Project description: Not available
| S-EPMC6197854 | biostudies-literature
Project description:During microRNA (miRNA)-guided gene silencing, Argonaute (Ago) proteins interact with a member of the TNRC6/GW protein family. Here we used a short GW protein-derived peptide fused to GST and demonstrate that it binds to Ago proteins with high affinity. This allows for the simultaneous isolation of all Ago protein complexes expressed in diverse species to identify associated proteins, small RNAs or target mRNAs. We refer to our method as Ago protein Affinity Purification by Peptides (Ago-APP). Comparison of small RNA lengths in total RNA and APP-enriched RNA samples
2015-09-08 | E-GEOD-70553 | biostudies-arrayexpress
Project description:During microRNA (miRNA)-guided gene silencing, Argonaute (Ago) proteins interact with a member of the TNRC6/GW protein family. Here we used a short GW protein-derived peptide fused to GST and demonstrate that it binds to Ago proteins with high affinity. This allows for the simultaneous isolation of all Ago protein complexes expressed in diverse species to identify associated proteins, small RNAs or target mRNAs. We refer to our method as Ago protein Affinity Purification by Peptides (Ago-APP).
2015-09-08 | GSE70553 | GEO
Project description:Proteins function in crowded cellular environments in which they must bind to specific target proteins but also avoid binding to many other off-target proteins. In large protein families this task is particularly challenging because many off-target proteins have very similar structures. How this specificity of physical protein-protein interactions in cellular networks is encoded and evolves is not very well understood. Here we address the question of specificity-encoding by comprehensively quantifying the effects of all mutations in one protein, JUN, on its binding to all other members of a protein family, the 54 human basic leucine zipper transcription factors. Fitting a global thermodynamic model to the data reveals that most affinity changing mutations equally affect JUN’s propensity to bind to all its interaction partners. Mutations that alter the specificity of binding are much rarer. These specificity-altering mutations are, however, distributed throughout the JUN interaction interface. JUN’s interaction specificity is encoded by both positive determinants that promote on-target interactions and negative determinants that prevent off-target interactions. Indeed, about half of the specificity-defining residues in JUN have dual functions and both promote on-target binding and prevent off-target binding. Whereas nearly all mutations that alter specificity are pleiotropic and also alter the affinity of binding to all interaction partners, the converse is not true with mutations outside of the interface able to tune affinity without affecting specificity. Our results provide the first global view of how mutations in a protein affect binding to all its potential interaction partners and reveal the distributed encoding of specificity and affinity in an interaction interface. They also show how the modular architecture of coiled-coils provides an elegant solution to the challenge of optimising specificity and affinity in a large protein family.
2024-05-02 | GSE245326 | GEO
Project description:It remains extraordinarily challenging to elucidate endogenous protein-protein interactions and proximities within the cellular milieu. The dynamic nature and the large range of affinities of these interactions augment the difficulty of this undertaking. Among the most useful tools for extracting such information are those based on affinity capture of target bait proteins in combination with mass spectrometric readout of the co-isolated species. Although highly enabling, the utility of affinity-based methods is generally limited by difficulties in distinguishing specific from non-specific interactors, preserving and isolating all unique interactions including those that are weak, transient or rapidly exchanging, and differentiating proximal interactions from those that are more distal. Here, we have devised and optimized a set of methods to address these challenges. The resulting pipeline involves flash-freezing cells in liquid nitrogen to preserve the cellular environment at the moment of freezing; cryomilling to fracture the frozen cells into intact sub-micron chunks to allow for rapid access of a chemical reagent and to stabilize the intact endogenous subcellular assemblies and interactors upon thawing; and utilizing the high reactivity of glutaraldehyde to achieve sufficiently rapid stabilization at low temperatures to preserve native cellular interactions. In the course of this work, we determined that relatively low molar ratios of glutaraldehyde to reactive amines within the cellular milieu were sufficient to preserve even labile and transient interactions. This mild treatment enables efficient and rapid affinity capture of the protein assemblies of interest under non-denaturing conditions, followed by bottom-up MS to identify and quantify the protein constituents. For convenience, we have termed this approach Stabilized Affinity Capture Mass Spectrometry (SAC-MS). Here, we demonstrate that SAC-MS allows us to stabilize and elucidate local, distant and transient protein interactions within complex cellular milieux, many of which are not observed in the absence of chemical stabilization.
2018-10-19 | PXD001262 | Pride
Project description:Thousands of protein domains encoded in the human genome function by binding up to a million short linear motifs embedded in intrinsically disordered regions of other proteins. How affinity and specificity are encoded in these binding domains and the motifs themselves is not well understood. The evolvability of binding specificity - how rapidly and extensively it can change upon mutation - is also largely unexplored, as is the contribution of ‘fuzzy’ dynamic residues to affinity and specificity in protein-protein interactions. Here we produce the first global map of affinity and specificity encoding in a globular protein domain. Quantifying >200,000 energetic interactions between the domain and ligand allows us to identify 20 major energetically coupled pairs of sites. These are organised into six modules, with the vast majority of mutations in each module only reprogramming specificity for a single position in the ligand. Nine of the major energetic couplings encoding specificity are direct structural contacts and 11 have an allosteric mechanism of action. The dynamic tail of the ligand is more robust to mutation than the structured portion but contributes additively to binding affinity and communicates with structured residues to enable changes in specificity. Our results present how affinity and specificity are encoded in a globular protein domain interacting with a disordered peptide and a direct comparison of the encoding of affinity and specificity in structured and dynamic molecular recognition.
2024-04-25 | GSE265816 | GEO
Project description:Identification of ECM3 interactors by affinity purification followed by mass spectrometry analysis.
2022-11-03 | PXD017773 | Pride
Project description:Myocyte Enhancer Factor 2 (MEF2) proteins are involved in multiple developmental, physiological, and pathological processes in vertebrates. Protein:protein interactions underlie the plethora of biological processes impacted by MEF2A, necessitating a detailed characterization of the MEF2A interactome. A nanobody based affinity-purification/mass spectrometry strategy was employed to achieve this goal. Specifically, the MEF2A protein complexes were captured from myogenic lysates using a GFP-tagged MEF2A protein immobilized with a GBP-nanobody followed by LC-MS/MS proteomic analysis to identify MEF2A interactors.
2024-02-27 | PXD050042 | Pride
Project description: Not available
| S-EPMC5071697 | biostudies-other