Project description:G protein-coupled receptors in intracellular organelles can be activated in response to membrane permeant ligands, which contributes to the diversity and specificity of agonist action. The opioid receptors (ORs) provide a striking example, where small molecule opioid drugs activate ORs in the Golgi apparatus within seconds of drug addition. To date, our knowledge on the signaling of intracellular GPCRs remains incomplete and it is unknown if the downstream events triggered by ORs in plasma membrane and Golgi apparatus differ. To address this gap, we analyzed OR-mediated gene expression changes upon treatment with impermeant peptide ligand DPDPE, permeant ligand SNC80 or ICI-SNC80 (Golgi-restricted signaling). We show that DOR activation in the Golgi does not trigger any gene transcription at these two time points as compare to plasma membrane receptors. The study delineates OR signal transduction with unprecedented resolution and reveals that the subcellular location defines the signaling effect promoted by opioid drugs.
Project description:G protein-coupled receptors in intracellular organelles can be activated in response to membrane permeant ligands, which contributes to the diversity and specificity of agonist action. The opioid receptors (ORs) provide a striking example, where small molecule opioid drugs activate ORs in the Golgi apparatus within seconds of drug addition. To date, our knowledge on the signaling of intracellular GPCRs remains incomplete and it is unknown if the downstream events triggered by ORs in plasma membrane and Golgi apparatus differ. To address this gap, we analyzed OR-mediated phosphorylation changes in cells treated with SNC80 (signaling control) or ICI-SNC80 (Golgi-restricted signaling) for 5 min or 25 min. We show that OR activation in the plasma membrane or Golgi apparatus have strikingly different downstream effects on protein phosphorylation. The study delineates OR signal transduction with unprecedented resolution and reveals that the subcellular location defines the signaling effect promoted by opioid drugs.
Project description:A deeper understanding of the regulation of G protein-coupled receptors (GPCRs) and their associated downstream cascades will provide critical insights into how these pathways shape human physiology and disease, and could yield novel therapeutic targets. Here, we validate and characterize RNA-binding motif 12 (Rbm12) as a repressor of GPCR/cAMP signaling. We established Rbm12 CRISPR KO HEK293 cells using two independent gRNAs and human iPSC-derived neurons (iNeuron) depleted of Rbm12 via CRISPR interference. Then, we performed basal gene expression profiling (HEK293) and basal + beta-2-adrenergic receptor induced (1 hour of 1 uM Isoproterenol) conditions (neurons).
Project description:G protein-coupled receptors (GPCRs) are seven integral transmembrane proteins that are the primary targets of almost 30% of approved drugs and continue to represent a major focus of pharmaceutical research. All of GPCR targeted medicines were discovered by classical medicinal chemistry approaches. After the first GPCR crystal structures were determined, the docking screens using these structures lead to discovery of more novel and potent ligands. There are over 360 pharmaceutically relevant GPCRs in the human genome and to date about only 30 of structures have been determined. For these reasons, computational techniques such as homology modeling and molecular dynamics simulations have proven their usefulness to explore the structure and function of GPCRs. Furthermore, structure-based drug design and in silico screening (High Throughput Docking) are still the most common computational procedures in GPCRs drug discovery. Moreover, ligand-based methods such as three-dimensional quantitative structure-selectivity relationships, are the ideal molecular modeling approaches to rationalize the activity of tested GPCR ligands and identify novel GPCR ligands. In this review, we discuss the most recent advances for the computational approaches to effectively guide selectivity and affinity of ligands. We also describe novel approaches in medicinal chemistry, such as the development of biased agonists, allosteric modulators, and bivalent ligands for class A GPCRs. Furthermore, we highlight some knockout mice models in discovering biased signaling selectivity.
Project description:The involvement of G-Protein-Coupled Receptors’ (GPCR) location bias in diverse cellular functions and their misregulation in pathology is an underexplored territory. HCAR1, a GPCR for lactate is linked to cancer progression, mainly due to Warburg effect, but its mechanism of action remains elusive. Here, we show HCAR1 has a nuclear localization, capable of signaling intranuclearly to induce nuclear-ERK and AKT phosphorylation concomitant with higher cancer cell proliferation and survival. We determine its nuclear interactome, proving its involvement in protein-translation and DNA-damage repair. Nuclear HCAR1 (N-HCAR1) directly interacts with chromatin/DNA promoting expression of genes involved in cellular migration. Notably, we show N-HCAR1 particularly regulates a broader transcriptomic signature than its PM counterpart, emphasizing on the facts that functional output of N-HCAR1 is larger than PM localized HCAR1. Our study presents several unprecedented processes by which a GPCR through location-biased activity regulate various cellular functions and how cancer cells exploit these.
Project description:The involvement of G-Protein-Coupled Receptors’ (GPCR) location bias in diverse cellular functions and their misregulation in pathology is an underexplored territory. HCAR1, a GPCR for lactate is linked to cancer progression, mainly due to Warburg effect, but its mechanism of action remains elusive. Here, we show HCAR1 has a nuclear localization, capable of signaling intranuclearly to induce nuclear-ERK and AKT phosphorylation concomitant with higher cancer cell proliferation and survival. We determine its nuclear interactome, proving its involvement in protein-translation and DNA-damage repair. Nuclear HCAR1 (N-HCAR1) directly interacts with chromatin/DNA promoting expression of genes involved in cellular migration. Notably, we show N-HCAR1 particularly regulates a broader transcriptomic signature than its PM counterpart, emphasizing on the facts that functional output of N-HCAR1 is larger than PM localized HCAR1. Our study presents several unprecedented processes by which a GPCR through location-biased activity regulate various cellular functions and how cancer cells exploit these.
Project description:affy_fsh_human - affy_fsh_human - - G protein-coupled receptors (GPCR) are centrally involved in most physiological processes and are a major drug targets. They transduce extracellular signals inside the cells through at least two different mechanisms: i) the classical coupling to heterotrimeric G proteins and ii) a newly discovered beta-arrestin-dependent pathway. The fundamental issue of the respective impacts that these two transduction mechanisms exert on gene regulation has not been clearly addressed to date. To tackle this question, we have developed two mutants of the follicle stimulating hormone (FSH) receptors which do not couple to G proteins upon FSH activation but continue to recruit beta-arrestins and signal through them.-In the present study, we compare the wild-type FSH receptor to either the R466A or the T469F mutants. These two mutations are localized in the second intra cellular loop of the FSH receptor and prevent G protein coupling to the active FSH receptor. Each receptor was permanently expressed in HEK-293 cells at comparable levels. Cells were treated or not for 6 hours with 3 nM FSH. Keywords: treated vs untreated comparison,wt vs mutant comparison 18 arrays - Human GenomeU133A 2.0