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ACS Central Science May 2024We report a blueprint for the rational design of G protein coupled receptor (GPCR) ligands with a tailored functional response. The present study discloses the...
We report a blueprint for the rational design of G protein coupled receptor (GPCR) ligands with a tailored functional response. The present study discloses the structure-based design of cannabinoid receptor type 2 (CBR) selective inverse agonists ()- and ()-, which were derived from privileged agonist HU-308 by introduction of a phenyl group at the -dimethylheptyl side chain. Epimer ()- exhibits high affinity for CBR with = 39.1 nM and serves as a platform for the synthesis of a wide variety of probes. Notably, for the first time these fluorescent probes retain their inverse agonist functionality, high affinity, and selectivity for CBR independent of linker and fluorophore substitution. Ligands ()-, ()-, and their derivatives act as inverse agonists in CBR-mediated cAMP as well as G protein recruitment assays and do not trigger β-arrestin-receptor association. Furthermore, no receptor activation was detected in live cell ERK phosphorylation and Ca-release assays. Confocal fluorescence imaging experiments with ()- (Alexa488) and ()- (Alexa647) probes employing BV-2 microglial cells visualized CBR expressed at endogenous levels. Finally, molecular dynamics simulations corroborate the initial docking data in which inverse agonists restrict movement of toggle switch Trp258 and thereby stabilize CBR in its inactive state.
PubMed: 38799662
DOI: 10.1021/acscentsci.3c01461 -
BioRxiv : the Preprint Server For... May 2024respond to mating pheromone through the GPCRs Ste2 and Ste3, which promote growth of a mating projection in response to ligand binding. This commitment to mating is...
UNLABELLED
respond to mating pheromone through the GPCRs Ste2 and Ste3, which promote growth of a mating projection in response to ligand binding. This commitment to mating is nutritionally and energetically taxing, and so we hypothesized that the cell may suppress mating signaling during starvation. We set out to investigate negative regulators of the mating pathway in nutritionally depleted environments. Here, we report that nutrient deprivation led to loss of Ste2 from the plasma membrane. Recapitulating this effect with nitrogen starvation led us to hypothesize that it was due to TORC1 signaling. Rapamycin inhibition of TORC1 impacted membrane levels of all yeast GPCRs. Inhibition of TORC1 also dampened mating pathway output. Deletion analysis revealed that TORC1 repression leads to α-arrestin-directed CME through TORC2-Ypk1 signaling. We then set out to determine whether major downstream effectors of the TOR complexes also downregulate pathway output during mating. We found that autophagy contributes to pathway downregulation through analysis of strains lacking . We also show that Ypk1 significantly reduced pathway output. Thus, both autophagy machinery and TORC2-Ypk1 signaling serve as attenuators of pheromone signaling during mating. Altogether, we demonstrate that the stress-responsive TOR complexes coordinate GPCR endocytosis and reduce the magnitude of pheromone signaling, in ligand-independent and ligand-dependent contexts.
ONE SENTENCE SUMMARY
TOR signaling regulates the localization of all GPCRs during starvation and suppress the mating pathway in the presence and absence of ligand.
PubMed: 38798445
DOI: 10.1101/2024.05.09.593412 -
International Journal of Molecular... May 2024Lysophosphatidic acid (LPA) type 3 (LPA) receptor mutants were generated in which the sites detected phosphorylated were substituted by non-phosphorylatable amino acids....
Lysophosphatidic acid (LPA) type 3 (LPA) receptor mutants were generated in which the sites detected phosphorylated were substituted by non-phosphorylatable amino acids. Substitutions were made in the intracellular loop 3 (IL3 mutant), the carboxyl terminus (Ctail), and both domains (IL3/Ctail). The wild-type (WT) receptor and the mutants were expressed in T-REx HEK293 cells, and the consequences of the substitutions were analyzed employing different functional parameters. Agonist- and LPA-mediated receptor phosphorylation was diminished in the IL3 and Ctail mutants and essentially abolished in the IL3/Ctail mutant, confirming that the main phosphorylation sites are present in both domains and their role in receptor phosphorylation eliminated by substitution and distributed in both domains. The WT and mutant receptors increased intracellular calcium and ERK 1/2 phosphorylation in response to LPA and PMA. The agonist, Ki16425, diminished baseline intracellular calcium, which suggests some receptor endogenous activity. Similarly, baseline ERK1/2 phosphorylation was diminished by Ki16425. An increase in baseline ERK phosphorylation was detected in the IL3/Ctail mutant. LPA and PMA-induced receptor interaction with β-arrestin 2 and LPA internalization were severely diminished in cells expressing the mutants. Mutant-expressing cells also exhibit increased baseline proliferation and response to different stimuli, which were inhibited by the antagonist Ki16425, suggesting a role of LPA receptors in this process. Migration in response to different attractants was markedly increased in the Ctail mutant, which the Ki16425 antagonist also attenuated. Our data experimentally show that receptor phosphorylation in the distinct domains is relevant for LPA receptor function.
Topics: Humans; Phosphorylation; Receptors, Lysophosphatidic Acid; HEK293 Cells; Lysophospholipids; Signal Transduction; Calcium; Endocytosis; Mutation
PubMed: 38791546
DOI: 10.3390/ijms25105508 -
Journal of Medicinal Chemistry Jun 2024Orphan GPR52 is emerging as a promising neurotherapeutic target. Optimization of previously reported lead employing an iterative drug design strategy led to the...
Orphan GPR52 is emerging as a promising neurotherapeutic target. Optimization of previously reported lead employing an iterative drug design strategy led to the identification of a series of unique GPR52 agonists, such as (), (), and (), with improved potency and efficacy. Intriguingly, compounds and showed greater bias for G protein/cAMP signaling and induced significantly less in vitro desensitization than parent compound , indicating that reducing GPR52 β-arrestin activity with biased agonism results in sustained GPR52 activation. Further exploration of compounds and indicated improved potency and efficacy, and excellent target selectivity, but limited brain exposure warranting further optimization. These balanced and biased GPR52 agonists provide important pharmacological tools to study GPR52 activation, signaling bias, and therapeutic potential for neuropsychiatric and neurological diseases.
Topics: Receptors, G-Protein-Coupled; Humans; Animals; Structure-Activity Relationship; Benzamides; HEK293 Cells; Drug Discovery; Mice; Rats; Signal Transduction
PubMed: 38788241
DOI: 10.1021/acs.jmedchem.4c00856 -
Biomolecules May 2024Small extracellular vesicles (sEVs) have emerged as promising therapeutic agents and drug delivery vehicles. Targeted modification of sEVs and their contents using...
Small extracellular vesicles (sEVs) have emerged as promising therapeutic agents and drug delivery vehicles. Targeted modification of sEVs and their contents using genetic modification strategies is one of the most popular methods. This study investigated the effects of p53 fusion with arrestin domain-containing protein 1 (ARRDC1) and CD63 on the generation of sEVs, p53 loading efficiency, and therapeutic efficacy. Overexpression of either ARRDC1-p53 (ARP) or CD63-p53 (CDP) significantly elevated p53 mRNA and protein levels. The incorporation of ARRDC1 and CD63 significantly enhanced HEK293T-sEV biogenesis, evidenced by significant increases in sEV-associated proteins TSG101 and LAMP1, resulting in a boost in sEV production. Importantly, fusion with ARRDC1 or CD63 substantially increased the efficiency of loading both p53 fusion proteins and its mRNA into sEVs. sEVs equipped with ARP or CDP significantly enhanced the enrichment of p53 fusion proteins and mRNA in p53-null H1299 cells, resulting in a marked increase in apoptosis and a reduction in cell proliferation, with ARP-sEVs demonstrating greater effectiveness than CDP-sEVs. These findings underscore the enhanced functionality of ARRDC1- and CD63-modified sEVs, emphasizing the potential of genetic modifications in sEV-based therapies for targeted cancer treatment.
Topics: Humans; Tetraspanin 30; Extracellular Vesicles; Tumor Suppressor Protein p53; HEK293 Cells; Cell Line, Tumor; Apoptosis; Cell Proliferation; Endosomal Sorting Complexes Required for Transport; Transcription Factors; DNA-Binding Proteins; RNA, Messenger; Lysosomal-Associated Membrane Protein 1
PubMed: 38785998
DOI: 10.3390/biom14050591 -
Cell Death & Disease May 2024Recruitment of fibroblasts to tumors and their activation into cancer-associated fibroblasts (CAFs) is a strategy used by tumor cells to direct extracellular matrix...
Recruitment of fibroblasts to tumors and their activation into cancer-associated fibroblasts (CAFs) is a strategy used by tumor cells to direct extracellular matrix (ECM) remodeling, invasion, and metastasis, highlighting the need to investigate the molecular mechanisms driving CAF function. Endothelin-1 (ET-1) regulates the communication between cancer and stroma and facilitates the progression of serous ovarian cancer (SOC). By binding to Endothelin A (ET) and B (ET) receptors, ET-1 enables the recruitment of β-arrestin1 (β-arr1) and the formation of signaling complexes that coordinate tumor progression. However, how ET-1 receptors might "educate" human ovarian fibroblasts (HOFs) to produce altered ECM and promote metastasis remains to be elucidated. This study identifies ET-1 as a pivotal factor in the activation of CAFs capable of proteolytic ECM remodeling and the generation of heterotypic spheroids containing cancer cells with a propensity to metastasize. An autocrine/paracrine ET-1/ETR/β-arr1 loop enhances HOF proliferation, upregulates CAF marker expression, secretes pro-inflammatory cytokines, and increases collagen contractility, and cell motility. Furthermore, ET-1 facilitates ECM remodeling by promoting the lytic activity of invadosome and activation of integrin β1. In addition, ET-1 signaling supports the formation of heterotypic HOF/SOC spheroids with enhanced ability to migrate through the mesothelial monolayer, and invade, representing metastatic units. The blockade of ETR or β-arr1 silencing prevents CAF activation, invadosome function, mesothelial clearance, and the invasive ability of heterotypic spheroids. In vivo, therapeutic inhibition of ETR using bosentan (BOS) significantly reduces the metastatic potential of combined HOFs/SOC cells, associated with enhanced apoptotic effects on tumor cells and stromal components. These findings support a model in which ET-1/β-arr1 reinforces tumor/stroma interaction through CAF activation and fosters the survival and metastatic properties of SOC cells, which could be counteracted by ETR antagonists.
Topics: Humans; Female; Ovarian Neoplasms; beta-Arrestin 1; Cancer-Associated Fibroblasts; Cell Line, Tumor; Podosomes; Endothelin-1; Neoplasm Metastasis; Receptor, Endothelin A; Signal Transduction; Extracellular Matrix; Cell Movement; Cell Proliferation; Animals; Fibroblasts; Neoplasm Invasiveness
PubMed: 38777849
DOI: 10.1038/s41419-024-06730-6 -
Drugs Jun 2024Tegileridine () is a small molecule μ-opioid receptor biased agonist developed by Jiangsu Hengrui Pharmaceuticals Co., Ltd for the treatment of postoperative pain.... (Review)
Review
Tegileridine () is a small molecule μ-opioid receptor biased agonist developed by Jiangsu Hengrui Pharmaceuticals Co., Ltd for the treatment of postoperative pain. Tegileridine selectively activates the G-protein-coupled pathway, which mediates strong central analgesic effects and only weakly activates the β-arrestin-2 pathway implicated in adverse events like respiratory depression and gastrointestinal dysfunction. In January 2024, tegileridine received its first approval in China for the treatment of moderate to severe pain after abdominal surgery. This article summarizes the milestones in the development of tegileridine leading to this first approval for the treatment of moderate to severe pain after abdominal surgery.
Topics: Humans; Drug Approval; Pain, Postoperative; Receptors, Opioid, mu; Analgesics, Opioid; China; Thiophenes; Spiro Compounds
PubMed: 38771484
DOI: 10.1007/s40265-024-02033-4 -
BioRxiv : the Preprint Server For... May 2024Rab GTPases act as molecular switches to regulate organelle homeostasis and membrane trafficking. Rab6 plays a central role in regulating cargo flux through the Golgi...
Rab GTPases act as molecular switches to regulate organelle homeostasis and membrane trafficking. Rab6 plays a central role in regulating cargo flux through the Golgi and is activated via nucleotide exchange by the Ric1-Rgp1 protein complex. Ric1-Rgp1 is conserved throughout eukaryotes but the structural and mechanistic basis for its function has not been established. Here we report the cryoEM structure of a Ric1-Rgp1-Rab6 complex representing a key intermediate of the nucleotide exchange reaction. This structure reveals the overall architecture of the complex and enabled us to identify interactions critical for proper recognition and activation of Rab6 on the Golgi membrane surface. Ric1-Rgp1 interacts with the nucleotide-binding domain of Rab6 using an uncharacterized helical domain, which we establish as a novel RabGEF domain by identifying residues required for Rab6 nucleotide exchange. Unexpectedly, the complex uses an arrestin fold to interact with the Rab6 hypervariable domain, indicating that interactions with the unstructured C-terminal regions of Rab GTPases may be a common specificity mechanism used by their activators. Collectively, our findings provide a detailed mechanistic understanding of regulated Rab6 activation at the Golgi.
PubMed: 38766083
DOI: 10.1101/2024.05.06.592747 -
Cell Reports May 2024The binding and function of β-arrestins are regulated by specific phosphorylation motifs present in G protein-coupled receptors (GPCRs). However, the exact arrangement...
The binding and function of β-arrestins are regulated by specific phosphorylation motifs present in G protein-coupled receptors (GPCRs). However, the exact arrangement of phosphorylated amino acids responsible for establishing a stable interaction remains unclear. We employ a 1D sequence convolution model trained on GPCRs with established β-arrestin-binding properties. With this approach, amino acid motifs characteristic of GPCRs that form stable interactions with β-arrestins can be identified, a pattern that we name "arreSTick." Intriguingly, the arreSTick pattern is also present in numerous non-receptor proteins. Using proximity biotinylation assay and mass spectrometry analysis, we demonstrate that the arreSTick motif controls the interaction between many non-receptor proteins and β-arrestin2. The HIV-1 Tat-specific factor 1 (HTSF1 or HTATSF1), a nuclear transcription factor, contains the arreSTick pattern, and its subcellular localization is influenced by β-arrestin2. Our findings unveil a broader role for β-arrestins in phosphorylation-dependent interactions, extending beyond GPCRs to encompass non-receptor proteins as well.
Topics: Phosphorylation; Humans; beta-Arrestins; Protein Binding; Amino Acid Motifs; HEK293 Cells; beta-Arrestin 2; Amino Acid Sequence; Protein Stability
PubMed: 38758647
DOI: 10.1016/j.celrep.2024.114241 -
PloS One 2024Loss-of-function mutations in the type 2 vasopressin receptor (V2R) are a major cause of congenital nephrogenic diabetes insipidus (cNDI). In the context of partial...
Loss-of-function mutations in the type 2 vasopressin receptor (V2R) are a major cause of congenital nephrogenic diabetes insipidus (cNDI). In the context of partial cNDI, the response to desmopressin (dDAVP) is partially, but not entirely, diminished. For those with the partial cNDI, restoration of V2R function would offer a prospective therapeutic approach. In this study, we revealed that OPC-51803 (OPC5) and its structurally related V2R agonists could functionally restore V2R mutants causing partial cNDI by inducing prolonged signal activation. The OPC5-related agonists exhibited functional selectivity by inducing signaling through the Gs-cAMP pathway while not recruiting β-arrestin1/2. We found that six cNDI-related V2R partial mutants (V882.53M, Y1283.41S, L1614.47P, T2736.37M, S3298.47R and S3338.51del) displayed varying degrees of plasma membrane expression levels and exhibited moderately impaired signaling function. Several OPC5-related agonists induced higher cAMP responses than AVP at V2R mutants after prolonged agonist stimulation, suggesting their potential effectiveness in compensating impaired V2R-mediated function. Furthermore, docking analysis revealed that the differential interaction of agonists with L3127.40 caused altered coordination of TM7, potentially contributing to the functional selectivity of signaling. These findings suggest that nonpeptide V2R agonists could hold promise as potential drug candidates for addressing partial cNDI.
Topics: Receptors, Vasopressin; Humans; HEK293 Cells; Diabetes Insipidus, Nephrogenic; Mutation; Signal Transduction; Cyclic AMP; Deamino Arginine Vasopressin; beta-Arrestins; Animals
PubMed: 38748623
DOI: 10.1371/journal.pone.0303507