scholarly journals Computationally designed GPCR quaternary structures bias signaling pathway activation

2021 ◽  
Author(s):  
Justine S Paradis ◽  
Xiang Feng ◽  
Brigitte Murat ◽  
Robert E Jefferson ◽  
Martyna E Szpakowska ◽  
...  
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
Structural Changes ◽  
Tertiary Structures ◽  
Cellular Processes ◽  
Pathway Activation ◽  
Biased Signaling ◽  
Vasopressin Receptors ◽  
State Models ◽  
Quaternary Structures

Communication across membranes controls critical cellular processes and is achieved by receptors translating extracellular signals into selective cytoplasmic responses. While receptor tertiary structures can now be readily characterized, receptor associations into quaternary structures are very challenging to study and their implications in signal transduction remain poorly understood. Here, we report a computational approach for predicting membrane receptor self-associations, and designing receptor oligomers with various quaternary structures and signaling properties. Using this approach, we designed chemokine receptor CXCR4 dimers with reprogrammed stabilities, conformations, and abilities to activate distinct intracellular signaling proteins. In agreement with our predictions, the designed CXCR4s dimerized through distinct conformations and displayed different quaternary structural changes upon activation. Consistent with the active state models, all engineered CXCR4 oligomers activated the G protein Gi, but only a few specific dimer structures also recruited β-arrestins. Overall, we demonstrate that quaternary structures represent an important unforeseen mechanism of receptor biased signaling and reveal the existence of a conformational switch at the dimer interface of several G protein-coupled receptors including CXCR4, mu-Opioid and type-2 Vasopressin receptors that selectively control the activation of G proteins vs β-arrestin-mediated pathways. The approach should prove useful for predicting and designing receptor associations to uncover and reprogram selective cellular signaling functions.

Abstract 057: β-arrestin1-Biased β1-adrenergic Receptor Signaling Regulates MicroRNA Processing

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Il-man Kim ◽  
Yongchao Wang ◽  
Kyoung-mi Park ◽  
Christopher J Traynham ◽  
Lan Mao ◽  
...  
Keyword(s):  
G Protein ◽  
Dependent Manner ◽  
Regulate Gene Expression ◽  
Cellular Processes ◽  
Biased Signaling ◽  
Microrna Processing ◽  
Cellular Pathways ◽  
Effector Pathways ◽  
Β Adrenergic Receptors ◽  
G Protein Coupled

MicroRNAs (miRs) are small, non-coding RNAs that function to post-transcriptionally regulate gene expression. First transcribed as long primary transcripts (pri-miRs), they are processed in the nucleus by Drosha into hairpin intermediates (pre-miRs) and further processed in the cytoplasm by Dicer into mature miRs where they regulate cellular processes following activation by a variety of signals such as those stimulated by β-adrenergic receptors (βARs). Initially discovered to desensitize βAR signaling, β-arrestins are now appreciated to transduce multiple effector pathways independent of G protein-mediated second messenger accumulation, a concept known as biased signaling. We previously showed that the β-arrestin-biased βAR agonist carvedilol activates cellular pathways in the heart. Here, we tested the hypothesis that carvedilol could activate β-arrestin-mediated miR maturation, thereby providing a novel potential mechanism for its cardioprotective effects. In human cells and mouse hearts, carvedilol (Carv) upregulates a subset of mature and pre-miRs but not their pri-miRs in a β1AR-, G protein-coupled receptor kinase (GRK) 5/6- and β-arrestin1-dependent manner (see figure). Mechanistically, β-arrestin1 regulates miR processing by forming a nuclear complex with hnRNPA1, a component of the Drosha microprocessor complex (see figure). In conclusion, our findings indicate a novel function for β1AR-mediated β-arrestin1 signaling in miR biogenesis, which may be linked to its cell survival mechanism and beneficial adaptive remodeling in the failing heart.

scholarly journals Intense Pulsed Electric Fields Denature Urease Proteins

2019 ◽  
Author(s):  
Gen Urabe ◽  
Toshiaki Katagiri ◽  
Sunao Katsuki
Keyword(s):  
Enzyme Activity ◽  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Pulsed Electric Fields ◽  
Tertiary Structures ◽  
Electrical Pulses ◽  
Nanosecond Pulsed Electric Fields ◽  
Quaternary Structures ◽  
And Function

AbstractThis paper describes the effects of nanosecond pulsed electric fields (nsPEFs) on the structure and enzyme activity of three kinds of proteins. Intense (up to 300 kV/cm), 5-ns-long electrical pulses were applied to solutions of lysozyme (14 kDa, monomer), albumin (67 kDa, monomer), and urease (480 kDa, hexamer). We analyzed the tertiary and quaternary structures of these proteins as well as their enzyme activity. The results indicated the deformation of both the quaternary and tertiary structures of urease upon exposure to an electric field of 250 kV/cm or more, whereas no structural changes were observed in lysozyme or albumin, even at 300 kV/cm. The enzyme activity of urease also decreased at field strengths of 250 kV/cm or more. Our experiments demonstrated that intense nsPEFs physically affect the conformation and function of some kinds of proteins. Such intense electric fields often occur on cell membranes when these are exposed to a moderate pulsed electric field.

scholarly journals Screening β-Arrestin Recruitment for the Identification of Natural Ligands for Orphan G-Protein–Coupled Receptors

2013 ◽  
Vol 18 (5) ◽  
pp. 599-609 ◽  
Author(s):  
Craig Southern ◽  
Jennifer M. Cook ◽  
Zaynab Neetoo-Isseljee ◽  
Debra L. Taylor ◽  
Catherine A. Kettleborough ◽  
...  
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
Orphan Receptors ◽  
Intracellular Signaling Pathway ◽  
Biased Signaling ◽  
Screening Assays ◽  
Orphan Gpcrs ◽  
G Protein Coupled ◽  
Orphan Gpcr ◽  
Native Ligand

A variety of G-protein–coupled receptor (GPCR) screening technologies have successfully partnered a number of GPCRs with their cognate ligands. GPCR-mediated β-arrestin recruitment is now recognized as a distinct intracellular signaling pathway, and ligand-receptor interactions may show a bias toward β-arrestin over classical GPCR signaling pathways. We hypothesized that the failure to identify native ligands for the remaining orphan GPCRs may be a consequence of biased β-arrestin signaling. To investigate this, we assembled 10 500 candidate ligands and screened 82 GPCRs using PathHunter β-arrestin recruitment technology. High-quality screening assays were validated by the inclusion of liganded receptors and the detection and confirmation of these established ligand-receptor pairings. We describe a candidate endogenous orphan GPCR ligand and a number of novel surrogate ligands. However, for the majority of orphan receptors studied, measurement of β-arrestin recruitment did not lead to the identification of cognate ligands from our screening sets. β-Arrestin recruitment represents a robust GPCR screening technology, and ligand-biased signaling is emerging as a therapeutically exploitable feature of GPCR biology. The identification of cognate ligands for the orphan GPCRs and the extent to which receptors may exist to preferentially signal through β-arrestin in response to their native ligand remain to be determined.

scholarly journals Influence of G protein-biased agonists of μ-opioid receptor on addiction-related behaviors

2021 ◽  
Author(s):  
Lucja Kudla ◽  
Ryszard Przewlocki
Keyword(s):  
G Protein ◽  
Opioid Receptor ◽  
Intracellular Signaling ◽  
Opioid Analgesics ◽  
Opioid Addiction ◽  
Receptor Agonists ◽  
Biased Signaling ◽  
Μ Opioid Receptor ◽  
Opioid Receptor Agonists

AbstractOpioid analgesics remain a gold standard for the treatment of moderate to severe pain. However, their clinical utility is seriously limited by a range of adverse effects. Among them, their high-addictive potential appears as very important, especially in the context of the opioid epidemic. Therefore, the development of safer opioid analgesics with low abuse potential appears as a challenging problem for opioid research. Among the last few decades, different approaches to the discovery of novel opioid drugs have been assessed. One of the most promising is the development of G protein-biased opioid agonists, which can activate only selected intracellular signaling pathways. To date, discoveries of several biased agonists acting via μ-opioid receptor were reported. According to the experimental data, such ligands may be devoid of at least some of the opioid side effects, such as respiratory depression or constipation. Nevertheless, most data regarding the addictive properties of biased μ-opioid receptor agonists are inconsistent. A global problem connected with opioid abuse also requires the search for effective pharmacotherapy for opioid addiction, which is another potential application of biased compounds. This review discusses the state-of-the-art on addictive properties of G protein-biased μ-opioid receptor agonists as well as we analyze whether these compounds can diminish any symptoms of opioid addiction. Finally, we provide a critical view on recent data connected with biased signaling and its implications to in vivo manifestations of addiction. Graphic abstract

Ion channels and G protein-coupled receptors as targets for invertebrate pest control: from past challenges to practical insecticides

2021 ◽  
Author(s):  
Yoshihisa Ozoe
Keyword(s):  
Ion Channels ◽  
G Protein ◽  
Pest Control ◽  
Gaba Receptors ◽  
Chloride Channels ◽  
Structural Changes ◽  
G Protein Coupled Receptors ◽  
Octopamine Receptors ◽  
Sites Of Action ◽  
G Protein Coupled

Abstract In the late 1970s, we discovered that toxic bicyclic phosphates inhibit the generation of miniature inhibitory junction potentials, implying their antagonism of γ-aminobutyric acid (GABA) receptors (GABARs; GABA-gated chloride channels). This unique mode of action provided a strong incentive for our research on GABARs in later years. Furthermore, minor structural changes conferred insect GABAR selectivity to this class of compounds, convincing us of the possibility of GABARs as targets for insecticides. Forty years later, third-generation insecticides acting as allosteric modulator antagonists at a distinctive site of action in insect GABARs were developed. G protein-coupled receptors (GPCRs) are also promising targets for pest control. We characterized phenolamine receptors functionally and pharmacologically. Of the tested receptors, β-adrenergic-like octopamine receptors were revealed to be the most sensitive to the acaricide/insecticide amitraz. Given the presence of multiple sites of action, ion channels and GPCRs remain potential targets for invertebrate pest control.

G-protein-coupled receptors signalling at the cell nucleus: an emerging paradigmThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 287-297 ◽  
Author(s):  
Fernand Gobeil ◽  
Audrey Fortier ◽  
Tang Zhu ◽  
Michela Bossolasco ◽  
Martin Leduc ◽  
...  
Keyword(s):  
G Protein ◽  
Cell Nucleus ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Cell Metabolism ◽  
Hormone Secretion ◽  
G Protein Coupled Receptors ◽  
A Cell ◽  
G Protein Coupled

G-protein-coupled receptors (GPCRs) comprise a wide family of monomeric heptahelical glycoproteins that recognize a broad array of extracellular mediators including cationic amines, lipids, peptides, proteins, and sensory agents. Thus far, much attention has been given towards the comprehension of intracellular signaling mechanisms activated by cell membrane GPCRs, which convert extracellular hormonal stimuli into acute, non-genomic (e.g., hormone secretion, muscle contraction, and cell metabolism) and delayed, genomic biological responses (e.g., cell division, proliferation, and apoptosis). However, with respect to the latter response, there is compelling evidence for a novel intracrine mode of genomic regulation by GPCRs that implies either the endocytosis and nuclear translocation of peripheral-liganded GPCR and (or) the activation of nuclearly located GPCR by endogenously produced, nonsecreted ligands. A noteworthy example of the last scenario is given by heptahelical receptors that are activated by bioactive lipoids (e.g., PGE2 and PAF), many of which may be formed from bilayer membranes including those of the nucleus. The experimental evidence for the nuclear localization and signalling of GPCRs will be reviewed. We will also discuss possible molecular mechanisms responsible for the atypical compartmentalization of GPCRs at the cell nucleus, along with their role in gene expression.

scholarly journals Imaging of persistent cAMP signaling by internalized G protein-coupled receptors

2010 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Davide Calebiro ◽  
Viacheslav O Nikolaev ◽  
Martin J Lohse
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
Current Model ◽  
Living Cells ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Optical Methods ◽  
Camp Signaling ◽  
Gpcr Signaling ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are the largest family of plasma membrane receptors. They mediate the effects of several endogenous cues and serve as important pharmacological targets. Although many biochemical events involved in GPCR signaling have been characterized in great detail, little is known about their spatiotemporal dynamics in living cells. The recent advent of optical methods based on fluorescent resonance energy transfer allows, for the first time, to directly monitor GPCR signaling in living cells. Utilizing these methods, it has been recently possible to show that the receptors for two protein/peptide hormones, the TSH and the parathyroid hormone, continue signaling to cAMP after their internalization into endosomes. This type of intracellular signaling is persistent and apparently triggers specific cellular outcomes. Here, we review these recent data and explain the optical methods used for such studies. Based on these findings, we propose a revision of the current model of the GPCR–cAMP signaling pathway to accommodate receptor signaling at endosomes.

scholarly journals Intracellular Signaling Pathway Activation via TGF-β Differs in the Anterior and Posterior Axis During Palatal Development

2016 ◽  
Vol 25 (2) ◽  
pp. 195-204
Author(s):  
Arisa Higa ◽  
Kyoko Oka ◽  
Michiko Kira-Tatsuoka ◽  
Shougo Tamura ◽  
Satoshi Itaya ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Intracellular Signaling ◽  
Intracellular Signaling Pathway ◽  
Pathway Activation ◽  
Palatal Development

scholarly journals Interplay between ADP-ribosyltransferases and essential cell signaling pathways controls cellular responses

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Flurina Boehi ◽  
Patrick Manetsch ◽  
Michael O. Hottiger
Keyword(s):  
Cell Signaling ◽  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Cellular Responses ◽  
Dynamic Regulation ◽  
Post Translational Modifications ◽  
Adp Ribosylation ◽  
Cellular Processes ◽  
Adp Ribosyltransferase ◽  
Cell Signaling Pathways

AbstractSignaling cascades provide integrative and interactive frameworks that allow the cell to respond to signals from its environment and/or from within the cell itself. The dynamic regulation of mammalian cell signaling pathways is often modulated by cascades of protein post-translational modifications (PTMs). ADP-ribosylation is a PTM that is catalyzed by ADP-ribosyltransferases and manifests as mono- (MARylation) or poly- (PARylation) ADP-ribosylation depending on the addition of one or multiple ADP-ribose units to protein substrates. ADP-ribosylation has recently emerged as an important cell regulator that impacts a plethora of cellular processes, including many intracellular signaling events. Here, we provide an overview of the interplay between the intracellular diphtheria toxin-like ADP-ribosyltransferase (ARTD) family members and five selected signaling pathways (including NF-κB, JAK/STAT, Wnt-β-catenin, MAPK, PI3K/AKT), which are frequently described to control or to be controlled by ADP-ribosyltransferases and how these interactions impact the cellular responses.

scholarly journals OR1D2 receptor mediates bourgeonal-induced human CatSper activation in a G-protein dependent manner

2019 ◽  
Author(s):  
Yi-min Cheng ◽  
Tao Luo ◽  
Zhen Peng ◽  
Hou-yang Chen ◽  
Jin Zhang ◽  
...  
Keyword(s):  
G Protein ◽  
Olfactory Receptor ◽  
Intracellular Signaling ◽  
Calcium Influx ◽  
Human Sperm ◽  
Camp Level ◽  
Dependent Manner ◽  
Intracellular Signaling Pathway ◽  
Camp Pathway ◽  
Sperm Chemotaxis

AbstractDuring fertilization, sperm are guided towards eggs by physiological chemokines, a process named sperm chemotaxis. Human sperm chemotaxis is speculated to be mediated by olfactory receptor OR1D2 in a pathway requiring calcium influx. Bourgeonal, an artificial ligand of OR1D2, can activate CatSper, the primary calcium channel in human sperm. However, whether bourgeonal-induced CatSper activation requires OR1D2 and how CatSper is activated remain unclear. Herein, we show that OR1D2 antibody can inhibit bourgeonal-induced CatSper activation and sperm chemotaxis, proving that OR1D2 mediates bourgeonal-induced CatSper activation. Furthermore, bourgeonal-evoked CatSper currents can be greatly suppressed by either GDP-β-S or antibody of Gαs. Interestingly, bourgeonal can transiently increase sperm cAMP level, and this effect can be abolished by OR1D2 antibody. Consistently, bourgeonal-induced CatSper activation can be inhibited by membrane adenylate cyclases inhibitor. Overall, our results indicate that bourgeonal activates CatSper via OR1D2-G protein-cAMP pathway. Although CatSper can be activated by various physiological and environmental factors, this study represents the most recent progress proving that CatSper can be indirectly activated by extracellular regulators through a G-protein-dependent intracellular signaling pathway.

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