title: Serine 363 is required for nociceptin/orphanin FQ opioid receptor (NOPR) desensitization, internalization, and arrestin signaling.
abstract: We determined the role of carboxyl-terminal regulation of NOPR (nociceptin, orphanin FQ receptor) signaling and function. We mutated C-terminal serine and threonine residues and examined their role in NOPR trafficking, homologous desensitization, and arrestin-dependent MAPK signaling. The NOPR agonist, nociceptin, caused robust NOPR-YFP receptor internalization, peaking at 30 min. Mutation of serine 337, 346, and 351, had no effect on NOPR internalization. However, mutation of C-terminal threonine 362, serine 363, and threonine 365 blocked nociceptin-induced internalization of NOPR. Furthermore, point mutation of only Ser-363 was sufficient to block NOPR internalization. Homologous desensitization of NOPR-mediated calcium channel blockade and inhibition of cAMP were also shown to require Ser-363. Additionally, NOPR internalization was absent when GRK3, and Arrestin3 were knocked down using siRNA, but not when GRK2 and Arrestin2 were knocked down. We also found that nociceptin-induced NOPR-mediated JNK but not ERK signaling requires Ser-363, GRK3, and Arrestin3. Dominant-positive Arrestin3 but not Arrestin2 was sufficient to rescue NOPR-S363A internalization and JNK signaling. These findings suggest that NOPR function may be regulated by GRK3 phosphorylation of Ser-363 and Arrestin3 and further demonstrates the complex nature of G-protein-dependent and -independent signaling in opioid receptors.
authors.affiliation: Department of Anesthesiology, Basic Research Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Zhang
authors.forename: William
authors.initials: W
authors.lastname: Planer
authors.forename: Edward R
authors.initials: ER
authors.lastname: Siuda
authors.forename: Hu-Chen
authors.initials: HC
authors.lastname: Zhao
authors.forename: Lucy
authors.initials: L
authors.lastname: Stickler
authors.forename: Steven D
authors.initials: SD
authors.lastname: Chang
authors.forename: Madison A
authors.initials: MA
authors.lastname: Baird
authors.forename: Yu-Qing
authors.initials: YQ
authors.lastname: Cao
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bruchas
mesh_terms: D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D054770:G-Protein-Coupled Receptor Kinase 3 / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism*; D018847:Opioid Peptides / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D011957:Receptors, Opioid / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D000094942:Nociceptin Receptor; D000097629:Nociceptin
chemical_list: D019390:Arrestins; D054770:G-Protein-Coupled Receptor Kinase 3; D048670:MAP Kinase Kinase 4; D018847:Opioid Peptides; D011957:Receptors, Opioid; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C082333:arrestin3; C517848:GRK3 protein, human; C000722283:OPRL1 protein, human