Language：English  

Cellular prion protein (PrP) is a membrane protein that is highly conserved among mammals and mainly expressed on the cell surface of neurons. Despite its reported interactions with various membrane proteins, no functional studies have so far been carried out on it, and its physiological functions remain unclear. Neuronal cell death has been observed in a PrP-knockout mouse model expressing Doppel protein, suggesting that PrP might be involved in Ca2+ signaling. In this study, we evaluated the binding of PrP to metabotropic glutamate receptor 1 (mGluR1) and found that wild-type PrP (PrP-wt) and mGluR1 co-immunoprecipitated in dual-transfected Neuro-2a (N2a) cells. Fluorescence resonance energy transfer analysis revealed an energy transfer between mGluR1-Cerulean and PrP-Venus. In order to determine whether PrP can modulate mGluR1 signaling, we performed Ca2+ imaging analyses following repetitive exposure to an mGluR1 agonist. Agonist stimulation induced synchronized Ca2+ oscillations in cells coexpressing PrP-wt and mGluR1. In contrast, N2a cells expressing PrP-ΔN failed to show ligand-dependent regulation of mGluR1-Ca2+ signaling, indicating that PrP can bind to mGluR1 and modulate its function to prevent irregular Ca2+ signaling and that its N-terminal region functions as a molecular switch during Ca2+ signaling.

DOI： 10.1016/j.bbrc.2020.02.102

PubMed

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Web of Science

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Web of Science

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Language：English   Publisher：JAPANESE PHARMACOLOGICAL SOC  

Interactions between mu-opioid receptor (mu OR) and cannabinoid CB(1) receptor (CB(1)R) were examined by morphological and electrophysiological methods. In baby hamster kidney (BHK) cells coexpressing mu OR fused to the yellow fluorescent protein Venus and CB(1)R fused to the cyan fluorescent protein Cerulean, both colors were detected on the cell surface; and fluorescence resonance energy transfer (FRET) analysis revealed that mu OR and CB(1)R formed a heterodimer. Coimmunoprecipitation and Western blotting analyses also confirmed the heterodimers of mu OR and CB(1)R. [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]enkephalin (DAMGO) or CP55,940 elicited K(+) currents in Xenopus oocytes expressing mu OR or CB(1)R together with G protein activated-inwardly rectifying K(+) channels (GIRKs), respectively. In oocytes coexpressing both receptors, either of which was fused to the chimeric G alpha protein G(qi5) that activates the phospholipase C pathway, both DAMGO and CP55,940 elicited Ca(2+)-activated Cl(-) currents, indicating that each agonist can induce responses through Gqi5 fused to either its own receptor or the other. Experiments with endogenous G(i/o). protein inactivation by pertussis toxin (PTX) supported the functional heterodimerization of mu OR/CB(1)R through PTX-insensitive G(qi5(m)) fused to each receptor. Thus, mu OR and CB(1)R form a heterodimer and transmit a signal through a common G protein. Our electrophysiological method could be useful for determination of signals mediated through heterodimerized G protein-coupled receptors.

DOI： 10.1254/jphs.08244FP

Web of Science

CiNii Article

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Presentation type：Poster presentation  

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Presentation type：Poster presentation  

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