scholarly journals Structural insights into distinct signaling profiles of the μOR activated by diverse agonists

2021 ◽  
Author(s):  
Qianhui Qu ◽  
Weijiao Huang ◽  
Deniz Aydin ◽  
Joseph M. Paggi ◽  
Alpay B. Seven ◽  
...  
Keyword(s):  
G Protein ◽  
Respiratory Depression ◽  
Animal Studies ◽  
Md Simulations ◽  
Active State ◽  
Μ Opioid Receptor ◽  
Mechanistic Basis ◽  
G Protein Coupled ◽  
Structural Insights ◽  
Different Parts

AbstractDrugs targeting the G protein-coupled μ-opioid receptor (μOR) are the most effective analgesics available but are also associated with fatal respiratory depression. While some partial opioid agonists appear to be safer than full agonists, the signaling pathways responsible for respiratory depression have yet to be elucidated. Here we investigated the structural and mechanistic basis of action of lofentanil (LFT) and mitragynine pseudoindoxyl (MP), two μOR agonists with different safety profiles. LFT, one of the most potent and lethal opioids, and MP, a derivative from the kratom plant with reduced respiratory depression in animal studies at equianalgesic doses, exhibited markedly different signaling efficacy profiles for G protein subtype activation and recruitment of β-arrestins. Cryo-EM structures of the μOR-Gi1 complex with MP (2.5Å) and LFT (3.2Å) revealed that the two ligands engage distinct sub-pockets, and molecular dynamics (MD) simulations showed additional differences in the binding site that propagate to the intracellular side of the receptor where G proteins and β-arrestins bind. While MP favors the precise G protein-bound active state observed in the cryo-EM structures, LFT favors a distinct active state. These results highlight how drugs engaging different parts of the μOR orthosteric pocket can lead to distinct signaling outcomes.

Structural insights into RAMP modification of secretin family G protein-coupled receptors: implications for drug development

2011 ◽  
Vol 32 (10) ◽  
pp. 591-600 ◽  
Author(s):  
Julia K. Archbold ◽  
Jack U. Flanagan ◽  
Harriet A. Watkins ◽  
Joseph J. Gingell ◽  
Debbie L. Hay
Keyword(s):  
Drug Development ◽  
G Protein ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled ◽  
Structural Insights

scholarly journals Mechanism of the G-protein mimetic nanobody binding to a muscarinic G-protein-coupled receptor

2018 ◽  
Vol 115 (12) ◽  
pp. 3036-3041 ◽  
Author(s):  
Yinglong Miao ◽  
J. Andrew McCammon
Keyword(s):  
Protein Binding ◽  
G Protein ◽  
Protein Interactions ◽  
Intracellular Signaling ◽  
Md Simulations ◽  
Binding Pocket ◽  
Signaling Proteins ◽  
Protein Protein Interactions ◽  
Intracellular Loops ◽  
G Protein Coupled

Protein–protein binding is key in cellular signaling processes. Molecular dynamics (MD) simulations of protein–protein binding, however, are challenging due to limited timescales. In particular, binding of the medically important G-protein-coupled receptors (GPCRs) with intracellular signaling proteins has not been simulated with MD to date. Here, we report a successful simulation of the binding of a G-protein mimetic nanobody to the M2 muscarinic GPCR using the robust Gaussian accelerated MD (GaMD) method. Through long-timescale GaMD simulations over 4,500 ns, the nanobody was observed to bind the receptor intracellular G-protein-coupling site, with a minimum rmsd of 2.48 Å in the nanobody core domain compared with the X-ray structure. Binding of the nanobody allosterically closed the orthosteric ligand-binding pocket, being consistent with the recent experimental finding. In the absence of nanobody binding, the receptor orthosteric pocket sampled open and fully open conformations. The GaMD simulations revealed two low-energy intermediate states during nanobody binding to the M2 receptor. The flexible receptor intracellular loops contribute remarkable electrostatic, polar, and hydrophobic residue interactions in recognition and binding of the nanobody. These simulations provided important insights into the mechanism of GPCR–nanobody binding and demonstrated the applicability of GaMD in modeling dynamic protein–protein interactions.

Structure network analysis to gain insights into GPCR function

2016 ◽  
Vol 44 (2) ◽  
pp. 613-618 ◽  
Author(s):  
Francesca Fanelli ◽  
Angelo Felline ◽  
Francesco Raimondi ◽  
Michele Seeber
Keyword(s):  
G Protein ◽  
Normal Mode Analysis ◽  
Network Models ◽  
Md Simulations ◽  
G Protein Coupled Receptors ◽  
Coarse Grained ◽  
Mode Analysis ◽  
Biomolecular Systems ◽  
Retinal Chromophore ◽  
G Protein Coupled

G protein coupled receptors (GPCRs) are allosteric proteins whose functioning fundamentals are the communication between the two poles of the helix bundle. Protein structure network (PSN) analysis is one of the graph theory-based approaches currently used to investigate the structural communication in biomolecular systems. Information on system's dynamics can be provided by atomistic molecular dynamics (MD) simulations or coarse grained elastic network models paired with normal mode analysis (ENM–NMA). The present review article describes the application of PSN analysis to uncover the structural communication in G protein coupled receptors (GPCRs). Strategies to highlight changes in structural communication upon misfolding, dimerization and activation are described. Focus is put on the ENM–NMA-based strategy applied to the crystallographic structures of rhodopsin in its inactive (dark) and signalling active (meta II (MII)) states, highlighting changes in structure network and centrality of the retinal chromophore in differentiating the inactive and active states of the receptor.

scholarly journals Novel Insights into the Crosstalk between Mineralocorticoid Receptor and G Protein-Coupled Receptors in Heart Adverse Remodeling and Disease

2018 ◽  
Author(s):  
Barbara M. Parker ◽  
Shelby L. Wertz ◽  
Celina M. Pollard ◽  
Victoria L. Desimine ◽  
Jennifer Maning ◽  
...  
Keyword(s):  
Heart Disease ◽  
G Protein ◽  
Mineralocorticoid Receptor ◽  
Animal Studies ◽  
Human Heart Failure ◽  
Gpcr Signaling ◽  
Cardiac Mr ◽  
Disease Therapy ◽  
Adverse Remodeling ◽  
G Protein Coupled

The mineralocorticoid hormone aldosterone regulates sodium and potassium homeostasis but also adversely modulates the maladaptive process of cardiac adverse remodeling post-myocardial infarction. Through activation of its mineralocorticoid receptor (MR), a classic steroid hormone receptor/transcription factor, aldosterone promotes inflammation and fibrosis of the heart, the vasculature, and the kidneys. This is why MR antagonists reduce morbidity and mortality of heart disease patients and are part of the mainstay pharmacotherapy of advanced human heart failure. A plethora of animal studies using cell type–specific targeting of the MR gene have established the importance of MR signaling and function in cardiac myocytes, vascular endothelial and smooth muscle cells, renal cells, and macrophages. In terms of its signaling properties, the MR is distinct from nuclear receptors in that it has, in reality, two physiological hormonal agonists: not only aldosterone but also cortisol. In fact, in several tissues, including in the myocardium, cortisol is the primary hormone activating the MR. There is a considerable amount of evidence indicating that the effects of the MR in each tissue expressing it depend on tissue- and ligand-specific engagement of molecular co-regulators that either activate or suppress its transcriptional activity. Identification of these co-regulators for every ligand that interacts with the MR in the heart (and in other tissues) is of utmost importance therapeutically, since it can not only help elucidate fully the pathophysiological ramifications of the cardiac MR`s actions but also help design and develop novel better MR antagonist drugs for heart disease therapy.  Among the various proteins the MR interacts with are molecules involved in cardiac G protein-coupled receptor (GPCR) signaling. This results in a significant amount of crosstalk between GPCRs and the MR, which can affect the latter`s activity dramatically in the heart and in other cardiovascular tissues. This review summarizes the current experimental evidence for this GPCR-MR crosstalk in the heart and discusses its pathophysiological implications for cardiac adverse remodeling as well as for heart disease therapy. Novel findings revealing non-conventional roles of GPCR signaling molecules, specifically of GPCR-kinase (GRK)-5, in cardiac MR regulation are also highlighted.

scholarly journals Neural basis of opioid-induced respiratory depression and its rescue

2020 ◽  
Author(s):  
Shijia Liu ◽  
Dongil Kim ◽  
Tae Gyu Oh ◽  
Gerald Pao ◽  
Jonghyun Kim ◽  
...  
Keyword(s):  
Respiratory Depression ◽  
G Protein Coupled Receptors ◽  
Opioid Overdose ◽  
Morphine Injection ◽  
Neural Basis ◽  
Lateral Parabrachial Nucleus ◽  
Promising Therapeutic Target ◽  
Μ Opioid Receptor ◽  
G Protein Coupled ◽  
Respiratory Rhythms

AbstractOpioid-induced respiratory depression (OIRD) causes death following an opioid overdose, yet the neurobiological mechanisms of this process are not well understood. Here, we show that neurons within the lateral parabrachial nucleus that express the μ-opioid receptor (PBLOprm1 neurons) are involved in OIRD pathogenesis. PBLOprm1 neuronal activity is tightly correlated with respiratory rate, and this correlation is abolished following morphine injection. Chemogenetic inactivation of PBLOprm1 neurons mimics OIRD in mice, whereas their chemogenetic activation following morphine injection rescues respiratory rhythms to baseline levels. We identified several excitatory G-protein coupled receptors expressed by PBLOprm1 neurons and show that agonists for these receptors restore breathing rates in mice experiencing OIRD. Thus, PBLOprm1 neurons are critical for OIRD pathogenesis, providing a promising therapeutic target for treating OIRD in patients.

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