scholarly journals Development of an Antigen-Antibody Co-Display System for Detecting Interaction of G-Protein-Coupled Receptors and Single-Chain Variable Fragments

2021 ◽  
Vol 22 (9) ◽  
pp. 4711
Author(s):  
Yinjie Zhang ◽  
Boyang Jason Wu ◽  
Xiaolan Yu ◽  
Ping Luo ◽  
Hao Ye ◽  
...  

G-protein-coupled receptors (GPCRs), especially chemokine receptors, are ideal targets for monoclonal antibody drugs. Considering the special multi-pass transmembrane structure of GPCR, it is often a laborious job to obtain antibody information about off-targets and epitopes on antigens. To accelerate the process, a rapid and simple method needs to be developed. The split-ubiquitin-based yeast two hybrid system (YTH) was used as a blue script for a new method. By fusing with transmembrane peptides, scFv antibodies were designed to be anchored on the cytomembrane, where the GPCR was co-displayed as well. The coupled split-ubiquitin system transformed the scFv-GPCR interaction signal into the expression of reporter genes. By optimizing the topological structure of scFv fusion protein and key elements, including signal peptides, transmembrane peptides, and flexible linkers, a system named Antigen-Antibody Co-Display (AACD) was established, which rapidly detected the interactions between antibodies and their target GPCRs, CXCR4 and CXCR5, while also determining the off-target antibodies and antibody-associated epitopes. The AACD system can rapidly determine the association between GPCRs and their candidate antibodies and shorten the research period for off-target detection and epitope identification. This system should improve the process of GPCR antibody development and provide a new strategy for GPCRs antibody screening.

2019 ◽  
Vol 119 (04) ◽  
pp. 534-541 ◽  
Author(s):  
Selin Gencer ◽  
Emiel van der Vorst ◽  
Maria Aslani ◽  
Christian Weber ◽  
Yvonne Döring ◽  
...  

AbstractInflammation has been well recognized as one of the main drivers of atherosclerosis development and therefore cardiovascular diseases (CVDs). It has been shown that several chemokines, small 8 to 12 kDa cytokines with chemotactic properties, play a crucial role in the pathophysiology of atherosclerosis. Chemokines classically mediate their effects by binding to G-protein-coupled receptors called chemokine receptors. In addition, chemokines can also bind to atypical chemokine receptors (ACKRs). ACKRs fail to induce G-protein-dependent signalling pathways and thus subsequent cellular response, but instead are able to internalize, scavenge or transport chemokines. In this review, we will give an overview of the current knowledge about the involvement of ACKR1–4 in CVDs and especially in atherosclerosis development. In the recent years, several studies have highlighted the importance of ACKRs in CVDs, although there are still several controversies and unexplored aspects that have to be further elucidated. A better understanding of the precise role of these atypical receptors may pave the way towards novel and improved therapeutic strategies.


2019 ◽  
Vol 5 (9) ◽  
pp. eaaw2778 ◽  
Author(s):  
Emily Lorenzen ◽  
Tea Dodig-Crnković ◽  
Ilana B. Kotliar ◽  
Elisa Pin ◽  
Emilie Ceraudo ◽  
...  

Receptor activity–modifying proteins (RAMPs) have been shown to modulate the functions of several G protein–coupled receptors (GPCRs), but potential direct interactions among the three known RAMPs and hundreds of GPCRs have never been investigated. Focusing mainly on the secretin-like family of GPCRs, we engineered epitope-tagged GPCRs and RAMPs, and developed a multiplexed suspension bead array (SBA) immunoassay to detect GPCR-RAMP complexes from detergent-solubilized lysates. Using 64 antibodies raised against the native proteins and 4 antibodies targeting the epitope tags, we mapped the interactions among 23 GPCRs and 3 RAMPs. We validated nearly all previously reported secretin-like GPCR-RAMP interactions, and also found previously unidentified RAMP interactions with additional secretin-like GPCRs, chemokine receptors, and orphan receptors. The results provide a complete interactome of secretin-like GPCRs with RAMPs. The SBA strategy will be useful to search for additional GPCR-RAMP complexes and other interacting membrane protein pairs in cell lines and tissues.


2019 ◽  
Author(s):  
Emily Lorenzen ◽  
Tea Dodig-Crnković ◽  
Ilana B. Kotliar ◽  
Elisa Pin ◽  
Emilie Ceraudo ◽  
...  

AbstractAlthough receptor activity-modifying proteins (RAMPs) have been shown to modulate the functions of several different G protein-coupled receptors (GPCRs), potential direct interactions among the three known RAMPs and hundreds of GPCRs has never been investigated. We engineered three epitope-tagged RAMPs and 23 epitope-tagged GPCRs, focusing on the secretin-like family of GPCRs, and developed a suspension bead array (SBA) immunoassay designed to detect RAMP-GPCR complexes. We then used 64 antibodies raised against native RAMPs and GPCRs, along with four antibodies targeting the epitope tags, to multiplex the SBA assay to detect and measure all possible combinations of interaction among the 23 GPCRs and three RAMPs. The results of the SBA assay provide a complete interactome of secretin-like GPCRs with RAMPs. We demonstrate direct interaction of previously reported secretin-like GPCRs whose functions are modulated by RAMPs. We also discovered novel sets of GPCR-RAMP interacting pairs, and found additional secretin-like GPCRs, chemokine receptors and orphan receptors that interact with RAMPs. Using in situ roximity ligation assay, we verified a subset of these novel GPCR-RAMP interactions in cell membranes. In total, we found GPCR-RAMP interactions for the majority of the 23 GPCRs tested. Each GPCR interacted with either all three RAMPs or with RAMP2 and RAMP3, with the exception of one GPCR that interacted with just RAMP3. In summary, we describe an SBA strategy that will be useful to search for GPCR-RAMP interactions in cell lines and tissues, and conclude that GPCR-RAMP interactions are more common than previously appreciated.


2020 ◽  
Vol 295 (30) ◽  
pp. 10153-10167 ◽  
Author(s):  
Mithu Baidya ◽  
Punita Kumari ◽  
Hemlata Dwivedi-Agnihotri ◽  
Shubhi Pandey ◽  
Badr Sokrat ◽  
...  

Agonist stimulation of G-protein–coupled receptors (GPCRs) typically leads to phosphorylation of GPCRs and binding to multifunctional proteins called β-arrestins (βarrs). The GPCR–βarr interaction critically contributes to GPCR desensitization, endocytosis, and downstream signaling, and GPCR–βarr complex formation can be used as a generic readout of GPCR and βarr activation. Although several methods are currently available to monitor GPCR–βarr interactions, additional sensors to visualize them may expand the toolbox and complement existing methods. We have previously described antibody fragments (FABs) that recognize activated βarr1 upon its interaction with the vasopressin V2 receptor C-terminal phosphopeptide (V2Rpp). Here, we demonstrate that these FABs efficiently report the formation of a GPCR–βarr1 complex for a broad set of chimeric GPCRs harboring the V2R C terminus. We adapted these FABs to an intrabody format by converting them to single-chain variable fragments and used them to monitor the localization and trafficking of βarr1 in live cells. We observed that upon agonist simulation of cells expressing chimeric GPCRs, these intrabodies first translocate to the cell surface, followed by trafficking into intracellular vesicles. The translocation pattern of intrabodies mirrored that of βarr1, and the intrabodies co-localized with βarr1 at the cell surface and in intracellular vesicles. Interestingly, we discovered that intrabody sensors can also report βarr1 recruitment and trafficking for several unmodified GPCRs. Our characterization of intrabody sensors for βarr1 recruitment and trafficking expands currently available approaches to visualize GPCR–βarr1 binding, which may help decipher additional aspects of GPCR signaling and regulation.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Yuan Liu ◽  
Guixiu Shi

Dendritic cells (DCs) are highly efficient antigen-presenting cells. The migratory properties of DCs give them the capacity to be a sentinel of the body and the vital role in the induction and regulation of adaptive immune responses. Therefore, it is important to understand the mechanisms in control of migration of DCs to lymphoid and nonlymphoid tissues. This may provide us novel insight into the clinical treatment of diseases such as autoimmune disease, infectious disease, and tumor. The chemotactic G protein-coupled receptors (GPCR) play a vital role in control of DCs migration. Here, we reviewed the recent advances regarding the role of GPCR in control of migration of subsets of DCs, with a focus on the chemokine receptors. Understanding subsets of DCs migration could provide a rational basis for the design of novel therapies in various clinical conditions.


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