scholarly journals Affinity Purification of NF1 Protein–Protein Interactors Identifies Keratins and Neurofibromin Itself as Binding Partners

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 650 ◽  
Author(s):  
Rachel M. Carnes ◽  
Robert A. Kesterson ◽  
Bruce R. Korf ◽  
James A. Mobley ◽  
Deeann Wallis
Keyword(s):  
Protein Interactions ◽  
Drug Targets ◽  
Affinity Purification ◽  
Neurofibromatosis Type ◽  
Hek293 Cells ◽  
Ras Signaling ◽  
Affinity Tag ◽  
Pathogenic Variants ◽  
Binding Partners ◽  
Keratin Expression

Neurofibromatosis Type 1 (NF1) is caused by pathogenic variants in the NF1 gene encoding neurofibromin. Definition of NF1 protein–protein interactions (PPIs) has been difficult and lacks replication, making it challenging to define binding partners that modulate its function. We created a novel tandem affinity purification (TAP) tag cloned in frame to the 3’ end of the full-length murine Nf1 cDNA (mNf1). We show that this cDNA is functional and expresses neurofibromin, His-Tag, and can correct p-ERK/ERK ratios in NF1 null HEK293 cells. We used this affinity tag to purify binding partners with Strep-Tactin®XT beads and subsequently, identified them via mass spectrometry (MS). We found the tagged mNf1 can affinity purify human neurofibromin and vice versa, indicating that neurofibromin oligomerizes. We identify 21 additional proteins with high confidence of interaction with neurofibromin. After Metacore network analysis of these 21 proteins, eight appear within the same network, primarily keratins regulated by estrogen receptors. Previously, we have shown that neurofibromin levels negatively regulate keratin expression. Here, we show through pharmacological inhibition that this is independent of Ras signaling, as the inhibitors, selumetinib and rapamycin, do not alter keratin expression. Further characterization of neurofibromin oligomerization and binding partners could aid in discovering new neurofibromin functions outside of Ras regulation, leading to novel drug targets.

scholarly journals Purification of viral genome-linked protein VPg from potato virus A-infected plants reveals several post-translationally modified forms of the protein

2008 ◽  
Vol 89 (6) ◽  
pp. 1509-1518 ◽  
Author(s):  
Anders Hafrén ◽  
Kristiina Mäkinen
Keyword(s):  
Potato Virus ◽  
Protein Interactions ◽  
Viral Genome ◽  
Affinity Purification ◽  
Infection Process ◽  
Dependent Manner ◽  
Affinity Tag ◽  
Post Translational Modifications ◽  
Potato Virus A ◽  
Protein Sample

In order to be able to analyse post-translational modifications and protein interactions of viral genome-linked protein VPg taking place during potato virus A (PVA) infection, an affinity tag-based purification system was developed by inserting a sequence encoding a six-histidine and haemagglutinin (HisHA) tag to the 3′ end of the VPg coding sequence within the infectious cDNA clone of PVA. The engineered virus was fully functional and the HisHA tag-encoding sequence remained stable in the PVA genome throughout the infection process. Purification under denaturing conditions resulted in a protein sample that contained multiple VPg and NIa forms carrying post-translational modifications that altered their isoelectric points. Non-modified tagged VPg (pI 8) was a minor product in the protein sample derived from total leaf proteins, but when the replication-associated membranes were used as starting material, its relative amount increased. Further characterization demonstrated that some of the PVA VPg isoforms were modified by multiple phosphorylation events. Purity of the proteins derived from the native purifications with either of the tags was evaluated. A clearly purer VPg sample was obtained by performing tandem affinity purification utilizing both tags sequentially. NIb, CI and HC-Pro co-purified in an affinity-tagged VPg-dependent manner, indicating that the system was able to isolate protein complexes operating during PVA infection.

scholarly journals Enzymatic RNA Biotinylation for Affinity Purification and Identification of RNA-protein Interactions

2020 ◽  
Author(s):  
Kayla N. Busby ◽  
Amitkumar Fulzele ◽  
Dongyang Zhang ◽  
Eric J. Bennett ◽  
Neal K. Devaraj
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
Noncoding Rna ◽  
Affinity Purification ◽  
Functional Characterization ◽  
Selective Enrichment ◽  
Binding Partners ◽  
Nucleotide Mutation ◽  
Rna Biology ◽  
And Function

ABSTRACTThroughout their cellular lifetime, RNA transcripts are bound to proteins, playing crucial roles in RNA metabolism, trafficking, and function. Despite the importance of these interactions, identifying the proteins that interact with an RNA of interest in mammalian cells represents a major challenge in RNA biology. Leveraging the ability to site-specifically and covalently label an RNA of interest using E. Coli tRNA guanine transglycosylase and an unnatural nucleobase substrate, we establish the identification of RNA-protein interactions and the selective enrichment of cellular RNA in mammalian systems. We demonstrate the utility of this approach through the identification of known binding partners of 7SK snRNA via mass spectrometry. Through a minimal 4-nucleotide mutation of the long noncoding RNA HOTAIR, enzymatic biotinylation enables identification putative HOTAIR binding partners in MCF7 breast cancer cells that suggest new potential pathways for oncogenic function. Furthermore, using RNA sequencing and qPCR, we establish that an engineered enzyme variant achieves high levels of labeling selectivity against the human transcriptome allowing for 145-fold enrichment of cellular RNA directly from mammalian cell lysates. The flexibility and breadth of this approach suggests that this system could be routinely applied to the functional characterization of RNA, greatly expanding the toolbox available for studying mammalian RNA biology.

scholarly journals A Leucine Rich Repeat Protein Provides a SHOC2 the RAS Circuit: A Structure-Function Perspective

2021 ◽  
Author(s):  
Jason J. Kwon ◽  
William C. Hahn
Keyword(s):  
Protein Interactions ◽  
Structural Features ◽  
Mitogen Activated Protein Kinase ◽  
Ras Signaling ◽  
Leucine Rich Repeat ◽  
Repeat Protein ◽  
Adaptive Resistance ◽  
Binding Partners ◽  
Mapk Inhibitors ◽  
Leucine Rich Repeat Protein

SHOC2 is a prototypical leucine-rich repeat protein that promotes downstream receptor tyrosine kinase (RTK)/RAS signaling and plays important roles in several cellular and developmental processes. Gain-of-function germline mutations of SHOC2 drive the RASopathy, Noonan-like syndrome, and SHOC2 mediates adaptive resistance to mitogen-activated protein kinase (MAPK) inhibitors. Similar to many scaffolding proteins, SHOC2 facilitates signal transduction by enabling proximal protein interactions and regulating the subcellular localization of its binding partners. Here we review the structural features of SHOC2 that mediate its known functions, discuss these elements in the context of various binding partners and signaling pathways, and highlight areas of SHOC2 biology where a consensus view has not yet emerged.

scholarly journals Comprehensive analysis of the host-virus interactome of SARS-CoV-2

2021 ◽  
Author(s):  
Zhen Chen ◽  
Chao Wang ◽  
Xu Feng ◽  
Litong Nie ◽  
Mengfan Tang ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Drug Targets ◽  
Affinity Purification ◽  
Functional Characterization ◽  
Viral Proteins ◽  
Host Cells ◽  
Virus Protein ◽  
N Protein ◽  
Protein Protein Interaction ◽  
Human Coronaviruses

Host-virus protein-protein interaction is the key component of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lifecycle. We conducted a comprehensive interactome study between the virus and host cells using tandem affinity purification and proximity labeling strategies and identified 437 human proteins as the high-confidence interacting proteins. Functional characterization and further validation of these interactions elucidated how distinct SARS-CoV-2 viral proteins participate in its lifecycle, and discovered potential drug targets to the treatment of COVID-19. The interactomes of two key SARS-CoV-2 encoded viral proteins, NSP1 and N protein, were compared with the interactomes of their counterparts in other human coronaviruses. These comparisons not only revealed common host pathways these viruses manipulate for their survival, but also showed divergent protein-protein interactions that may explain differences in disease pathology. This comprehensive interactome of coronavirus disease-2019 provides valuable resources for understanding and treating this disease.

scholarly journals Mapping the SARS-CoV-2–Host Protein–Protein Interactome by Affinity Purification Mass Spectrometry and Proximity-Dependent Biotin Labeling: A Rational and Straightforward Route to Discover Host-Directed Anti-SARS-CoV-2 Therapeutics

2021 ◽  
Vol 22 (2) ◽  
pp. 532
Author(s):  
Rosa Terracciano ◽  
Mariaimmacolata Preianò ◽  
Annalisa Fregola ◽  
Corrado Pelaia ◽  
Tiziana Montalcini ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drug Discovery ◽  
Protein Interactions ◽  
Drug Targets ◽  
Affinity Purification ◽  
Drug Repurposing ◽  
Host Protein ◽  
Host Cells ◽  
Traditional Drug ◽  
Approved Drugs

Protein–protein interactions (PPIs) are the vital engine of cellular machinery. After virus entry in host cells the global organization of the viral life cycle is strongly regulated by the formation of virus-host protein interactions. With the advent of high-throughput -omics platforms, the mirage to obtain a “high resolution” view of virus–host interactions has come true. In fact, the rapidly expanding approaches of mass spectrometry (MS)-based proteomics in the study of PPIs provide efficient tools to identify a significant number of potential drug targets. Generation of PPIs maps by affinity purification-MS and by the more recent proximity labeling-MS may help to uncover cellular processes hijacked and/or altered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), providing promising therapeutic targets. The possibility to further validate putative key targets from high-confidence interactions between viral bait and host protein through follow-up MS-based multi-omics experiments offers an unprecedented opportunity in the drug discovery pipeline. In particular, drug repurposing, making use of already existing approved drugs directly targeting these identified and validated host interactors, might shorten the time and reduce the costs in comparison to the traditional drug discovery process. This route might be promising for finding effective antiviral therapeutic options providing a turning point in the fight against the coronavirus disease-2019 (COVID-19) outbreak.

scholarly journals Computational identification of human biological processes and protein sequence motifs putatively targeted by SARS-CoV-2 proteins using protein-protein interaction networks

2020 ◽  
Author(s):  
Rachel Nadeau ◽  
Soroush Shahryari Fard ◽  
Amit Scheer ◽  
Emily Roth ◽  
Dallas Nygard ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Sequence ◽  
Drug Targets ◽  
Motif Discovery ◽  
Hek293 Cells ◽  
Sequence Motif ◽  
Sequence Motifs ◽  
Protein Protein Interaction ◽  
Human Proteins ◽  
Protein Sequence Motifs

AbstractWhile the COVID-19 pandemic is causing important loss of life, knowledge of the effects of the causative SARS-CoV-2 virus on human cells is currently limited. Investigating protein-protein interactions (PPIs) between viral and host proteins can provide a better understanding of the mechanisms exploited by the virus and enable the identification of potential drug targets. We therefore performed an in-depth computational analysis of the interactome of SARS-CoV-2 and human proteins in infected HEK293 cells published by Gordon et al. to reveal processes that are potentially affected by the virus and putative protein binding sites. Specifically, we performed a set of network-based functional and sequence motif enrichment analyses on SARS-CoV-2-interacting human proteins and on a PPI network generated by supplementing viral-host PPIs with known interactions. Using a novel implementation of our GoNet algorithm, we identified 329 Gene Ontology terms for which the SARS-CoV-2-interacting human proteins are significantly clustered in the network. Furthermore, we present a novel protein sequence motif discovery approach, LESMoN-Pro, that identified 9 amino acid motifs for which the associated proteins are clustered in the network. Together, these results provide insights into the processes and sequence motifs that are putatively implicated in SARS-CoV-2 infection and could lead to potential therapeutic targets.

scholarly journals A SARS-CoV-2-Human Protein-Protein Interaction Map Reveals Drug Targets and Potential Drug-Repurposing

2020 ◽  
Author(s):  
David E. Gordon ◽  
Gwendolyn M. Jang ◽  
Mehdi Bouhaddou ◽  
Jiewei Xu ◽  
Kirsten Obernier ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Drug Targets ◽  
Affinity Purification ◽  
Drug Repurposing ◽  
Human Protein ◽  
Protein Protein Interaction ◽  
Human Proteins ◽  
Interaction Map ◽  
Novel Coronavirus ◽  
Approved Drugs

ABSTRACTAn outbreak of the novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 290,000 people since the end of 2019, killed over 12,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven efficacy nor are there vaccines for its prevention. Unfortunately, the scientific community has little knowledge of the molecular details of SARS-CoV-2 infection. To illuminate this, we cloned, tagged and expressed 26 of the 29 viral proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), which identified 332 high confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 existing FDA-approved drugs, drugs in clinical trials and/or preclinical compounds, that we are currently evaluating for efficacy in live SARS-CoV-2 infection assays. The identification of host dependency factors mediating virus infection may provide key insights into effective molecular targets for developing broadly acting antiviral therapeutics against SARS-CoV-2 and other deadly coronavirus strains.

Identification of binding partners of CsaA - an archaeal chaperonic pro-tein of Picrophilus torridus

2020 ◽  
Vol 27 ◽  
Author(s):  
Neelja Singhal ◽  
Archana Sharma ◽  
Manisha Aswal ◽  
Nirpendra Singh ◽  
Manish Kumar ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Citrate Synthase ◽  
Elongation Factor ◽  
Trna Synthetase ◽  
Strong Interactions ◽  
Beta Chain ◽  
Protein Protein Interactions ◽  
Uncharacterized Protein ◽  
Binding Partners ◽  
Picrophilus Torridus

Background:: CsaA is among the few chaperones which are present in both bacteria and archaea, but absent in eukaryotes. There are no reports on interactome analysis of CsaA from archaea, till date. Identification of binding partners of CsaA might be helpful in understanding CsaA-associated processes in Picrophilus torridus– an extreme thermoaci-dophilic euryarchaeon. Objectives:: The present study was conducted to identify the binding partners of CsaA of P. torridus (PtCsaA). Methods:: The binding partners of PtCsaA were isolated and identified using a pull down assay and liquid chromatography-mass spectrometry (LC-MS). Results:: The results revealed twelve potential binding partners of CsaA. These were thermosome subunits (Q6KZS2 and Q6L132), nascent polypeptide-associated complex protein (Q6L1N3), elongation factor 1-alpha (Q6L202), uncharacterized protein (Q6L0Y6), citrate synthase (Q6L0M8), asparaginyl-tRNA synthetase (Q6L0M5), succinyl-CoA synthetase beta chain (Q6L0B4), pyruvate ferredoxin oxidoreductase alpha and beta chain proteins (Q6KZA7 and Q6KZA6, respectively), malate dehydrogenase (Q6L0C3) and reversed fumarylacetoacetase (Q6KZ97). Functional categorization revealed that of these, six proteins were involved in energy metabolic pathways, three were archaeal chaperones, two were involved in trans-lation and one might be a transcription regulator. STRING-based analysis of the protein-protein interactions of the experi-mental interactome revealed strong interactions among them. Conclusion:: PtCsaA might be a multifaceted protein which besides translation might also play important role in metabolic processes of P. torridus. However, further experiments investigating the binding partners of CsaA in other archaea are re-quired for a better understanding of CsaA-associated processes in archaea.

Affinity Tags for Protein Purification

2020 ◽  
Vol 21 (8) ◽  
pp. 821-830
Author(s):  
Vibhor Mishra
Keyword(s):  
Protein Purification ◽  
Protein Complexes ◽  
Affinity Purification ◽  
Protein Domain ◽  
Affinity Tag ◽  
Small Peptides ◽  
Affinity Tags ◽  
C Terminus ◽  
Solubility Enhancers ◽  
As Solubility

The affinity tags are unique proteins/peptides that are attached at the N- or C-terminus of the recombinant proteins. These tags help in protein purification. Additionally, some affinity tags also serve a dual purpose as solubility enhancers for challenging protein targets. By applying a combinatorial approach, carefully chosen affinity tags designed in tandem have proven to be very successful in the purification of single proteins or multi-protein complexes. In this mini-review, the key features of the most commonly used affinity tags are discussed. The affinity tags have been classified into two significant categories, epitope tags, and protein/domain tags. The epitope tags are generally small peptides with high affinity towards a chromatography resin. The protein/domain tags often perform double duty as solubility enhancers as well as aid in affinity purification. Finally, protease-based affinity tag removal strategies after purification are discussed.

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