The NTSR1 neurotensin receptor (NTSR1) is a G protein-coupled receptor (GPCR) found in the brain and peripheral tissues with neurotensin (NTS) being its endogenous peptide ligand. In the brain, NTS modulates dopamine neuronal activity, induces opioid-independent analgesia, and regulates food intake. Recent studies indicate that biasing NTSR1 toward β-arrestin signaling can attenuate the actions of psychostimulants and other drugs of abuse. Here, we provide the cryoEM structures of NTSR1 ternary complexes with heterotrimeric Gq and GoA with and without the brain-penetrant small-molecule SBI-553. In functional studies, we discovered that SBI-553 displays complex allosteric actions exemplified by negative allosteric modulation for G proteins that are Gα subunit selective and positive allosteric modulation and agonism for β-arrestin translocation at NTSR1. Detailed structural analysis of the allosteric binding site illuminated the structural determinants for biased allosteric modulation of SBI-553 on NTSR1.
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http://dx.doi.org/10.1021/acs.biochem.3c00029 | DOI Listing |
Cell Biochem Biophys
December 2024
Research Center of Neurology, Moscow, Russia.
Allopregnanolone (Allo) is a positive allosteric modulator of the GABA receptor, and amiloride (Ami) is a competitive antagonist of the GABA receptor. The purpose of this work was to study the combined effect of Allo and Ami on functional activity of GABA receptor. The GABA-induced chloride current (I) was measured in isolated Purkinje cells of rat cerebellum using the patch-clamp technique and a system of fast application.
View Article and Find Full Text PDFBiomed Pharmacother
December 2024
Center of Excellence on Natural Products for Neuroprotection and Anti-Ageing, Chulalongkorn University, Bangkok 10330, Thailand; Research, Innovation and International Affairs, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand. Electronic address:
Model organisms are commonly used to study human diseases; we set out to understand the relevance of several model organisms with relation to the σ1R protein. The study explored the interactions of σ1R with various agonists, antagonists across different species. Ligand and protein-protein (σ1R-BiP) docking approaches were used to understand the significance of σ1R in modulating neuroprotective mechanisms and its potential role in Alzheimer's.
View Article and Find Full Text PDFPLoS Comput Biol
December 2024
Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, Canada.
Treatment for major depressive disorder (depression) often has partial efficacy and a large portion of patients are treatment resistant. Recent studies implicate reduced somatostatin (SST) interneuron inhibition in depression, and new pharmacology boosting this inhibition via positive allosteric modulators of α5-GABAA receptors (α5-PAM) offers a promising effective treatment. However, testing the effect of α5-PAM on human brain activity is limited, meriting the use of detailed simulations.
View Article and Find Full Text PDFJ Chem Inf Model
December 2024
Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey.
Genetically encoded fluorescent biosensors (GEFBs) have become indispensable tools for visualizing biological processes A typical GEFB is composed of a sensory domain (SD) that undergoes a conformational change upon ligand binding or enzymatic reaction; the SD is genetically fused with a fluorescent protein (FP). The changes in the SD allosterically modulate the chromophore environment whose spectral properties are changed. Single fluorescent (FP)-based biosensors, a subclass of GEFBs, offer a simple experimental setup; they are easy to produce in living cells, structurally stable, and simple to use due to their single-wavelength operation.
View Article and Find Full Text PDFJ Med Chem
December 2024
Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona 08028, Spain.
Activation of cannabinoid CB receptors (CBR) by agonists induces analgesia but also induces cognitive impairment through the heteromer formed between CBR and the serotonin 5HT receptor (5HTR). This side effect poses a serious drawback in the therapeutic use of cannabis for pain alleviation. Peptides designed from the transmembrane helices of CBR, which are predicted to bind 5HTR and alter the stability of the CBR-5HTR heteromer, have been shown to avert CBR agonist-induced cognitive impairment while preserving analgesia.
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