G protein-coupled receptors (GPCRs) are one of the largest families of transmembrane receptors and a major target of current therapeutic drugs. At the signaling level, it has become clear that ligands acting on the same receptor can activate multiple and sometime opposing signaling cascades; a process defined as functional selectivity or biased agonism. One of the main effectors of functional selectivity are beta-arrestins, multifunction proteins recruited to activated receptors. However, how receptor activation translates into beta-arrestin signaling is not clearly defined. Our preliminary work combining state-of-the-art live cell imaging with molecular and biochemical techniques identifies ligand-specific dwell times, the time receptors are clustered into individual endocytic pits before endocytosis, as a mechanism by which receptors can control beta-arrestin mediated signaling. Our hypothesis suggests that ligands induce specific phosphorylations at the receptor level, eliciting specific endocytic dwell times during which beta-arrestins remain recruited and engaged in signaling. We propose to define a mechanism by which the Cannabinoid 1 Receptor (CB1R), one of the most abundant receptors in the CNS and target of cannabis, controls beta-arrestin signaling during endocytic dwell times.
Our aims are: 1) Characterize ligand-specific dwell times of the CB1R to test our hypothesis that ligands can elicit specific dwell times that ar independent of their endocytic efficacy. 2) Define the mechanisms underlying ligand-specific dwell times of the CB1R. We will test the hypothesis that dwell times are controlled by ligand-specific phosphorylation profiles (bar-codes) of the receptor. Alternative mechanisms will be also investigated. 3) Determine if beta-arrestin signaling is the physiological target of ligand specific dwell times in heterologous systems and native tissue. Finally, we will test different manipulations to control arrestin signaling by altering CB1R dwell times.

Public Health Relevance

Nearly one million people seek treatment for marijuana dependence every year in the US; however, there are no current medications to prevent or cure cannabis-related disorders (cannabis abuse and dependence, psychotic disorders, and anxiety disorder). Cannabinoid receptors are the target of ?9-THC, the main psychoactive ingredient in marijuana. Our preliminary work identifies a mechanism by which non-canonical signaling (beta-arrestin signaling) from these receptors can be modulated, specific endocytic dwell times, while providing alternative approaches to control it. Our aims will define this mechanism. Ligand mechanisms could be modulated to enhance the benefits, while reducing negative effects of cannabis. Moreover, these mechanisms could be targeted to control beta-arrestin signaling from any GPCR.

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
Research Project (R01)
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Molecular Neuropharmacology and Signaling Study Section (MNPS)
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Purohit, Vishnudutt
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University of Puerto Rico Med Sciences
San Juan
United States
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Nogueras-Ortiz, Carlos; Roman-Vendrell, Cristina; Mateo-Semidey, Gabriel E et al. (2017) Retromer stops beta-arrestin 1-mediated signaling from internalized cannabinoid 2 receptors. Mol Biol Cell 28:3554-3561
Delgado-Peraza, Francheska; Ahn, Kwang H; Nogueras-Ortiz, Carlos et al. (2016) Mechanisms of Biased ?-Arrestin-Mediated Signaling Downstream from the Cannabinoid 1 Receptor. Mol Pharmacol 89:618-29
Kendall, Debra A; Yudowski, Guillermo A (2016) Cannabinoid Receptors in the Central Nervous System: Their Signaling and Roles in Disease. Front Cell Neurosci 10:294
Delgado-Peraza, Francheska; Nogueras-Ortiz, Carlos; Acevedo Canabal, Agnes M et al. (2016) Imaging GPCRs trafficking and signaling with total internal reflection fluorescence microscopy in cultured neurons. Methods Cell Biol 132:25-33
Nogueras-Ortiz, Carlos; Yudowski, Guillermo A (2016) The Multiple Waves of Cannabinoid 1 Receptor Signaling. Mol Pharmacol 90:620-626
Palacio, Stephanie; Velázquez-Marrero, Cristina; Marrero, Héctor G et al. (2015) Time-Dependent Effects of Ethanol on BK Channel Expression and Trafficking in Hippocampal Neurons. Alcohol Clin Exp Res 39:1619-31
Roman-Vendrell, Cristina; Yudowski, Guillermo Ariel (2015) Real-time imaging of mu opioid receptors by total internal reflection fluorescence microscopy. Methods Mol Biol 1230:79-86
Roman-Vendrell, Cristina; Chevalier, Michael; Acevedo-Canabal, Agnes M et al. (2014) Imaging of kiss-and-run exocytosis of surface receptors in neuronal cultures. Front Cell Neurosci 8:363
Flores-Otero, Jacqueline; Ahn, Kwang H; Delgado-Peraza, Francheska et al. (2014) Ligand-specific endocytic dwell times control functional selectivity of the cannabinoid receptor 1. Nat Commun 5:4589