scholarly journals Selective protein O-GlcNAcylation in cells by a proximity-directed O-GlcNAc transferase

2019 ◽  
Author(s):  
Daniel H. Ramirez ◽  
Chanat Aonbangkhen ◽  
Hung-Yi Wu ◽  
Jeffrey A. Naftaly ◽  
Stephanie Tang ◽  
...  
Keyword(s):  
Target Protein ◽  
Protein Signaling ◽  
Substrate Selection ◽  
Loss Of Function ◽  
Chemical Proteomics ◽  
Post Translational Modifications ◽  
Target Proteins ◽  
Glcnac Transferase ◽  
Selective Increase ◽  
In Cells

AbstractO-Linked N-acetylglucosamine (O-GlcNAc) is a monosaccharide that plays an essential role in cellular signaling throughout the nucleocytoplasmic proteome of eukaryotic cells. Yet, the study of post-translational modifications like O-GlcNAc has been limited by the lack of strategies to induce O-GlcNAcylation on a target protein in cells. Here, we report a generalizable genetic strategy to induce O-GlcNAc to specific target proteins in cells using a nanobody as a proximity-directing agent fused to O-GlcNAc transferase (OGT). Fusion of a nanobody that recognizes GFP (nGFP) or a nanobody that recognizes the four-amino acid sequence EPEA (nEPEA) to OGT(4), a truncated form of OGT, yielded a nanobody-OGT(4) construct that selectively delivered O-GlcNAc to the target protein (e.g., JunB, cJun, Nup62) and reduced alteration of global O-GlcNAc levels in the cell. Quantitative chemical proteomics confirmed the selective increase in O-GlcNAc to the target protein by nanobody-OGT(4). Glycoproteomics revealed that nanobody-OGT(4) or full-length OGT produced a similar glycosite profile on the target protein. Finally, we demonstrate the ability to selectively target endogenous α-synuclein for glycosylation in HEK293T cells. Thus, the use of nanobodies to redirect OGT substrate selection is a versatile strategy to induce glycosylation of desired target proteins in cells that will facilitate discovery of O-GlcNAc functions and provide a mechanism to engineer O-GlcNAc signaling. The proximity-directed OGT approach for protein-selective O-GlcNAcylation is readily translated to additional protein targets and nanobodies that may constitute a generalizable strategy to control post-translational modifications in cells.Significance StatementNature uses post-translational modifications (PTMs) like glycosylation as a mechanism to alter protein signaling and function. However, the study of these modified proteins in cells is confined to loss-of-function strategies, such as mutagenic elimination of the modification site. Here, we report a generalizable strategy for induction of O-GlcNAc to a protein target in cells. The O-GlcNAc modification is installed by O-GlcNAc transferase (OGT) to thousands of nucleocytoplasmic proteins. Fusion of a nanobody to OGT enables the selective increase of O-GlcNAc levels on a series of target proteins. The described approach will facilitate direct studies of O-GlcNAc and its regulatory enzymes and drive new approaches to engineer protein signaling via a strategy that may be conceptually translatable to additional PTMs.

Drug repurposing using similarity-based target prediction, docking studies and scaffold hopping of lefamulin

2020 ◽  
Vol 17 ◽  
Author(s):  
Shikha Sharma ◽  
Shweta Sharma ◽  
Vaishali Pathak ◽  
Parwinder Kaur ◽  
Rajesh Kumar Singh
Keyword(s):  
In Silico ◽  
Target Prediction ◽  
Drug Repurposing ◽  
Docking Studies ◽  
Target Protein ◽  
Future Perspective ◽  
Antibacterial Drug ◽  
Scaffold Hopping ◽  
Target Proteins ◽  
Renin Inhibitors

Aim: To investigate and validate the potential target proteins for drug repurposing of newly FDA approved antibacterial drug. Background: Drug repurposing is the process of assigning indications for drugs other than the one(s) that they were initially developed for. Discovery of entirely new indications from already approved drugs is highly lucrative as it minimizes the pipeline of the drug development process by reducing time and cost. In silico driven technologies made it possible to analyze molecules for different target proteins which are not yet explored. Objective: To analyze possible targets proteins for drug repurposing of lefamulin and their validation. Also, in silico prediction of novel scaffolds from lefamulin has been performed for assisting medicinal chemists in future drug design. Methods: A similarity-based prediction tool was employed for predicting target protein and further investigated using docking studies on PDB ID: 2V16. Besides, various in silico tools were employed for prediction of novel scaffolds from lefamulin using scaffold hopping technique followed by evaluation with various in silico parameters viz., ADME, synthetic accessibility and PAINS. Results: Based on the similarity and target prediction studies, renin is found as the most probable target protein for lefamulin. Further, validation studies using docking of lefamulin revealed the significant interactions of lefamulin with the binding pocket of the target protein. Also, three novel scaffolds were predicted using scaffold hopping technique and found to be in the limit to reduce the chances of drug failure in the physiological system during the last stage approval process. Conclusion: To encapsulate the future perspective, lefamulin may assist in the development of the renin inhibitors and, also three possible novel scaffolds with good pharmacokinetic profile can be developed into both as renin inhibitors and for bacterial infections.

scholarly journals Regulating the Regulators: Mechanisms of Substrate Selection of the O-GlcNAc Cycling Enzymes OGT and OGA

Glycobiology ◽  
2021 ◽  
Author(s):  
Hannah M Stephen ◽  
Trevor M Adams ◽  
Lance Wells
Keyword(s):  
Nutrient Sensing ◽  
Substrate Selection ◽  
Disease States ◽  
Dynamic Modification ◽  
Selection For ◽  
Outstanding Question ◽  
Glcnac Transferase ◽  
Future Work ◽  
Partner Proteins ◽  
Selection Of

Abstract Thousands of nuclear and cytosolic proteins are modified with a single β-N-acetylglucosamine on serine and threonine residues in mammals, a modification termed O-GlcNAc. This modification is essential for normal development and plays important roles in virtually all intracellular processes. Additionally, O-GlcNAc is involved in many disease states, including cancer, diabetes, and X-linked intellectual disability. Given the myriad of functions of the O-GlcNAc modification, it is therefore somewhat surprising that O-GlcNAc cycling is mediated by only two enzymes: the O-GlcNAc transferase (OGT), which adds O-GlcNAc, and the O-GlcNAcase (OGA), which removes it. A significant outstanding question in the O-GlcNAc field is how do only two enzymes mediate such an abundant and dynamic modification. In this review, we explore the current understanding of mechanisms for substrate selection for the O-GlcNAc cycling enzymes. These mechanisms include direct substrate interaction with specific domains of OGT or OGA, selection of interactors via partner proteins, posttranslational modification of OGT or OGA, nutrient sensing, and localization alteration. Altogether, current research paints a picture of an exquisitely regulated and complex system by which OGT and OGA select substrates. We also make recommendations for future work, toward the goal of identifying interaction mechanisms for specific substrates that may be able to be exploited for various research and medical treatment goals.

scholarly journals Protein Sensing Device with Multi-Recognition Ability Composed of Self-Organized Glycopeptide Bundle

2020 ◽  
Vol 22 (1) ◽  
pp. 366
Author(s):  
Mao Arai ◽  
Tomohiro Miura ◽  
Yuriko Ito ◽  
Takatoshi Kinoshita ◽  
Masahiro Higuchi
Keyword(s):  
Binding Site ◽  
Lipid Bilayer ◽  
Structural Changes ◽  
Bilayer Membrane ◽  
Lipid Bilayer Membrane ◽  
Target Protein ◽  
Self Organization ◽  
Specific Response ◽  
Target Proteins ◽  
Recognition Ability

We designed and synthesized amphiphilic glycopeptides with glucose or galactose at the C-terminals. We observed the protein-induced structural changes of the amphiphilic glycopeptide assembly in the lipid bilayer membrane using transmission electron microscopy (TEM) and Fourier transform infrared reflection-absorption spectra (FTIR-RAS) measurements. The glycopeptides re-arranged to form a bundle that acted as an ion channel due to the interaction among the target protein and the terminal sugar groups of the glycopeptides. The bundle in the lipid bilayer membrane was fixed on a gold-deposited quartz crystal microbalance (QCM) electrode by the membrane fusion method. The protein-induced re-arrangement of the terminal sugar groups formed a binding site that acted as a receptor, and the re-binding of the target protein to the binding site induced the closing of the channel. We monitored the detection of target proteins by the changes of the electrochemical properties of the membrane. The response current of the membrane induced by the target protein recognition was expressed by an equivalent circuit consisting of resistors and capacitors when a triangular voltage was applied. We used peanut lectin (PNA) and concanavalin A (ConA) as target proteins. The sensing membrane induced by PNA shows the specific response to PNA, and the ConA-induced membrane responded selectively to ConA. Furthermore, PNA-induced sensing membranes showed relatively low recognition ability for lectin from Ricinus Agglutinin (RCA120) and mushroom lectin (ABA), which have galactose binding sites. The protein-induced self-organization formed the spatial arrangement of the sugar chains specific to the binding site of the target protein. These findings demonstrate the possibility of fabricating a sensing device with multi-recognition ability that can recognize proteins even if the structure is unknown, by the protein-induced self-organization process.

O‐GlcNAc Engineering on a Target Protein in Cells with Nanobody‐OGT and Nanobody‐splitOGA

2021 ◽  
Vol 1 (5) ◽  
Author(s):  
Daniel H. Ramirez ◽  
Yun Ge ◽  
Christina M. Woo
Keyword(s):  
Target Protein ◽  
In Cells

scholarly journals Rgs4 is a regulator of mTOR activity required for motoneuron axon outgrowth and neuronal development in zebrafish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aya Mikdache ◽  
Marie-José Boueid ◽  
Lorijn van der Spek ◽  
Emilie Lesport ◽  
Brigitte Delespierre ◽  
...  
Keyword(s):  
Nervous System ◽  
G Protein ◽  
Neural Development ◽  
Neuronal Development ◽  
Axon Outgrowth ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Loss Of Function ◽  
G Protein Coupled

AbstractThe Regulator of G protein signaling 4 (Rgs4) is a member of the RGS proteins superfamily that modulates the activity of G-protein coupled receptors. It is mainly expressed in the nervous system and is linked to several neuronal signaling pathways; however, its role in neural development in vivo remains inconclusive. Here, we generated and characterized a rgs4 loss of function model (MZrgs4) in zebrafish. MZrgs4 embryos showed motility defects and presented reduced head and eye sizes, reflecting defective motoneurons axon outgrowth and a significant decrease in the number of neurons in the central and peripheral nervous system. Forcing the expression of Rgs4 specifically within motoneurons rescued their early defective outgrowth in MZrgs4 embryos, indicating an autonomous role for Rgs4 in motoneurons. We also analyzed the role of Akt, Erk and mechanistic target of rapamycin (mTOR) signaling cascades and showed a requirement for these pathways in motoneurons axon outgrowth and neuronal development. Drawing on pharmacological and rescue experiments in MZrgs4, we provide evidence that Rgs4 facilitates signaling mediated by Akt, Erk and mTOR in order to drive axon outgrowth in motoneurons and regulate neuronal numbers.

scholarly journals Villin Severing Activity Enhances Actin-based Motility In Vivo

2007 ◽  
Vol 18 (3) ◽  
pp. 827-838 ◽  
Author(s):  
Céline Revenu ◽  
Matthieu Courtois ◽  
Alphée Michelot ◽  
Cécile Sykes ◽  
Daniel Louvard ◽  
...  
Keyword(s):  
Shigella Flexneri ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Loss Of Function ◽  
Mesenchymal Transition ◽  
Capping Protein ◽  
Function Strategy ◽  
In Cells

Villin, an actin-binding protein associated with the actin bundles that support microvilli, bundles, caps, nucleates, and severs actin in a calcium-dependant manner in vitro. We hypothesized that the severing activity of villin is responsible for its reported role in enhancing cell plasticity and motility. To test this hypothesis, we chose a loss of function strategy and introduced mutations in villin based on sequence comparison with CapG. By pyrene-actin assays, we demonstrate that this mutant has a strongly reduced severing activity, whereas nucleation and capping remain unaffected. The bundling activity and the morphogenic effects of villin in cells are also preserved in this mutant. We thus succeeded in dissociating the severing from the three other activities of villin. The contribution of villin severing to actin dynamics is analyzed in vivo through the actin-based movement of the intracellular bacteria Shigella flexneri in cells expressing villin and its severing variant. The severing mutations abolish the gain of velocity induced by villin. To further analyze this effect, we reconstituted an in vitro actin-based bead movement in which the usual capping protein is replaced by either the wild type or the severing mutant of villin. Confirming the in vivo results, villin-severing activity enhances the velocity of beads by more than two-fold and reduces the density of actin in the comets. We propose a model in which, by severing actin filaments and capping their barbed ends, villin increases the concentration of actin monomers available for polymerization, a mechanism that might be paralleled in vivo when an enterocyte undergoes an epithelio-mesenchymal transition.

Monitoring Drug Target Engagement in Cells and Tissues Using the Cellular Thermal Shift Assay

Science ◽  
2013 ◽  
Vol 341 (6141) ◽  
pp. 84-87 ◽  
Author(s):  
Daniel Martinez Molina ◽  
Rozbeh Jafari ◽  
Marina Ignatushchenko ◽  
Takahiro Seki ◽  
E. Andreas Larsson ◽  
...  
Keyword(s):  
Drug Target ◽  
Drug Transport ◽  
Drug Binding ◽  
Target Engagement ◽  
Tissue Samples ◽  
Target Proteins ◽  
Thermal Shift Assay ◽  
Cellular Thermal Shift Assay ◽  
Thermal Shift ◽  
In Cells

The efficacy of therapeutics is dependent on a drug binding to its cognate target. Optimization of target engagement by drugs in cells is often challenging, because drug binding cannot be monitored inside cells. We have developed a method for evaluating drug binding to target proteins in cells and tissue samples. This cellular thermal shift assay (CETSA) is based on the biophysical principle of ligand-induced thermal stabilization of target proteins. Using this assay, we validated drug binding for a set of important clinical targets and monitored processes of drug transport and activation, off-target effects and drug resistance in cancer cell lines, as well as drug distribution in tissues. CETSA is likely to become a valuable tool for the validation and optimization of drug target engagement.

scholarly journals Emerging mass spectrometry-based proteomics methodologies for novel biomedical applications

2020 ◽  
Vol 48 (5) ◽  
pp. 1953-1966
Author(s):  
Lindsay K. Pino ◽  
Jacob Rose ◽  
Amy O'Broin ◽  
Samah Shah ◽  
Birgit Schilling
Keyword(s):  
Mass Spectrometry ◽  
Human Health ◽  
Protein Complexes ◽  
Protein Quantification ◽  
Intact Protein ◽  
Protein Signaling ◽  
Post Translational Modifications ◽  
Protein Protein Interaction ◽  
Health And Disease ◽  
Proteomics Research

Research into the basic biology of human health and disease, as well as translational human research and clinical applications, all benefit from the growing accessibility and versatility of mass spectrometry (MS)-based proteomics. Although once limited in throughput and sensitivity, proteomic studies have quickly grown in scope and scale over the last decade due to significant advances in instrumentation, computational approaches, and bio-sample preparation. Here, we review these latest developments in MS and highlight how these techniques are used to study the mechanisms, diagnosis, and treatment of human diseases. We first describe recent groundbreaking technological advancements for MS-based proteomics, including novel data acquisition techniques and protein quantification approaches. Next, we describe innovations that enable the unprecedented depth of coverage in protein signaling and spatiotemporal protein distributions, including studies of post-translational modifications, protein turnover, and single-cell proteomics. Finally, we explore new workflows to investigate protein complexes and structures, and we present new approaches for protein–protein interaction studies and intact protein or top-down MS. While these approaches are only recently incipient, we anticipate that their use in biomedical MS proteomics research will offer actionable discoveries for the improvement of human health.

A cascading reaction sequence involving ligand-directed azaelectrocyclization and autooxidation-induced fluorescence recovery enables visualization of target proteins on the surfaces of live cells

2014 ◽  
Vol 12 (9) ◽  
pp. 1412-1418 ◽  
Author(s):  
Katsunori Tanaka ◽  
Masataka Kitadani ◽  
Ayumi Tsutsui ◽  
Ambara R. Pradipta ◽  
Rie Imamaki ◽  
...  
Keyword(s):  
Target Protein ◽  
Fluorescence Recovery ◽  
Live Cells ◽  
Reaction Sequence ◽  
Target Proteins

A general probe designed to induce a cascading sequence of reactions on a target protein was efficiently synthesized.

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