Cannabinoid Receptor-Related Orphan G Protein-Coupled Receptors

Abstract G-protein-coupled receptors (GPCRs) play important roles in cellular functions. However, their intracellular organization is largely unknown. Through investigation of the cannabinoid receptor 1 (CB1), we discovered periodically repeating clusters of CB1 hotspots within the axons of neurons. We observed these CB1 hotspots interact with the membrane-associated periodic skeleton (MPS) forming a complex crucial in the regulation of CB1 signaling. Furthermore, we found that CB1 hotspot periodicity increased upon CB1 agonist application, and these activated CB1 displayed less dynamic movement compared to non-activated CB1. Our results suggest that CB1 forms periodic hotspots organized by the MPS as a mechanism to increase signaling efficacy upon activation.

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Cholesterol as a modulator of cannabinoid receptor CB2 signaling

Scientific Reports ◽

10.1038/s41598-021-83245-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alexei Yeliseev ◽

Malliga R. Iyer ◽

Thomas T. Joseph ◽

Nathan J. Coffey ◽

Resat Cinar ◽

...

Keyword(s):

G Protein ◽

Md Simulation ◽

Cannabinoid Receptor ◽

Partial Agonist ◽

G Protein Coupled Receptors ◽

Affinity Ligands ◽

Drug Candidates ◽

Different Types ◽

G Protein Coupled ◽

Specific Ligand

AbstractSignaling through integral membrane G protein-coupled receptors (GPCRs) is influenced by lipid composition of cell membranes. By using novel high affinity ligands of human cannabinoid receptor CB2, we demonstrate that cholesterol increases basal activation levels of the receptor and alters the pharmacological categorization of these ligands. Our results revealed that (2-(6-chloro-2-((2,2,3,3-tetramethylcyclopropane-1-carbonyl)imino)benzo[d]thiazol-3(2H)-yl)ethyl acetate ligand (MRI-2646) acts as a partial agonist of CB2 in membranes devoid of cholesterol and as a neutral antagonist or a partial inverse agonist in cholesterol-containing membranes. The differential effects of a specific ligand on activation of CB2 in different types of membranes may have implications for screening of drug candidates in a search of modulators of GPCR activity. MD simulation suggests that cholesterol exerts an allosteric effect on the intracellular regions of the receptor that interact with the G-protein complex thereby altering the recruitment of G protein.

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Organized cannabinoid receptor distribution in neurons revealed by super-resolution fluorescence imaging

10.1101/2020.03.22.002642 ◽

2020 ◽

Author(s):

Hui Li ◽

Jie Yang ◽

Tian Cuiping ◽

Min Diao ◽

Quan Wang ◽

...

Keyword(s):

G Protein ◽

Fluorescence Imaging ◽

Cannabinoid Receptor ◽

Super Resolution ◽

G Protein Coupled Receptors ◽

Cellular Functions ◽

Cannabinoid Receptor 1 ◽

Intracellular Organization ◽

Dynamic Movement ◽

G Protein Coupled

AbstractG-protein-coupled receptors (GPCRs) play important roles in cellular functions. However, their intracellular organization is largely unknown. Through investigation of the cannabinoid receptor 1 (CB1), we discovered periodically repeating clusters of CB1 hotspots within the axons of neurons. We observed these CB1 hotspots interact with the membrane-associated periodic skeleton (MPS) forming a complex crucial in the regulation of CB1 signaling. Furthermore, we found that CB1 hotspot periodicity increased upon CB1 agonist application, and these activated CB1 displayed less dynamic movement compared to non-activated CB1. Our results suggest that CB1 forms periodic hotspots organized by the MPS as a mechanism to increase signaling efficacy when being activated.

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Quantifying the Kinetics of Signaling and Arrestin Recruitment by Nervous System G-Protein Coupled Receptors

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2021.814547 ◽

2022 ◽

Vol 15 ◽

Author(s):

Sam R. J. Hoare ◽

Paul H. Tewson ◽

Shivani Sachdev ◽

Mark Connor ◽

Thomas E. Hughes ◽

...

Keyword(s):

Nervous System ◽

G Protein ◽

Cannabinoid Receptor ◽

Temporal Analysis ◽

G Protein Coupled Receptors ◽

Live Cells ◽

Optical Signals ◽

Behavior Understanding ◽

Synthetic Cannabinoid Receptor Agonists ◽

G Protein Coupled

Neurons integrate inputs over different time and space scales. Fast excitatory synapses at boutons (ms and μm), and slow modulation over entire dendritic arbors (seconds and mm) are all ultimately combined to produce behavior. Understanding the timing of signaling events mediated by G-protein-coupled receptors is necessary to elucidate the mechanism of action of therapeutics targeting the nervous system. Measuring signaling kinetics in live cells has been transformed by the adoption of fluorescent biosensors and dyes that convert biological signals into optical signals that are conveniently recorded by microscopic imaging or by fluorescence plate readers. Quantifying the timing of signaling has now become routine with the application of equations in familiar curve fitting software to estimate the rates of signaling from the waveform. Here we describe examples of the application of these methods, including (1) Kinetic analysis of opioid signaling dynamics and partial agonism measured using cAMP and arrestin biosensors; (2) Quantifying the signaling activity of illicit synthetic cannabinoid receptor agonists measured using a fluorescent membrane potential dye; (3) Demonstration of multiplicity of arrestin functions from analysis of biosensor waveforms and quantification of the rates of these processes. These examples show how temporal analysis provides additional dimensions to enhance the understanding of GPCR signaling and therapeutic mechanisms in the nervous system.

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