title: PDZK1/NHERF3 differentially regulates corticotropin-releasing factor receptor 1 and serotonin 2A receptor signaling and endocytosis.
abstract: The corticotropin-releasing factor receptor 1 (CRFR1) and serotonin 2A receptor (5-HT2AR) are linked to cellular mechanisms underlying stress anxiety and depression. Both receptors are members of the G protein-coupled receptor (GPCR) superfamily and encode class I PSD-95/DiscsLarge/Zona Occludens 1 (PDZ) binding motifs (-S/T-x-V/I/L) at the end of their carboxyl-terminal tails. We have identified PDZK1, also referred to as Na(+)/H(+) exchange regulatory cofactor 3 (NHERF3) as both a CRFR1- and 5-HT2AR-interacting protein. We have examined whether PDZK1 plays a role in regulating both CRFR1 and 5-HT2AR activity. We find that while PDZK1 interactions with CRFR1 are PDZ binding motif-dependent, PDZK1 associates with 5-HT2AR in a PDZ binding motif-independent manner and CRFR1 expression, but not 5-HT2AR expression, redistributes PDZK1 to the plasma membrane in PDZ binding motif-dependent manner. PDZK1, negatively regulates 5-HT2AR endocytosis and has no effect upon 5-HT2AR-mediated ERK1/2 phosphorylation. In contrast, PDZK1 overexpression does not affect CRFR1 endocytosis, but selectively increases CRFR1-stimulated ERK1/2 phosphorylation. Similar to what has been previously reported for PSD-95 and SAP97, PDZK1 positively influences 5-HT2AR-stimulated inositol phosphate formation, but does not contribute to the regulation of CRFR1-mediated cAMP signaling. Taken together, these results indicate that PDZK1 differentially regulates the signaling and trafficking of CRFR1 and 5-HT2AR via PDZ-dependent and -independent mechanisms, respectively.
authors.affiliation: J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Walther
authors.affiliation: J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute.
authors.forename: Fabiana A
authors.initials: FA
authors.lastname: Caetano
authors.affiliation: J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute; Department of Physiology and Pharmacology, University of Western Ontario, 100 Perth Dr., London, Ontario, Canada, N6A5K8.
authors.forename: Henry A
authors.initials: HA
authors.lastname: Dunn
authors.affiliation: J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute; Department of Physiology and Pharmacology, University of Western Ontario, 100 Perth Dr., London, Ontario, Canada, N6A5K8. Electronic address: ferguson@robarts.ca.
authors.forename: Stephen S G
authors.initials: SS
authors.lastname: Ferguson
mesh_terms: D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004705:Endocytosis / Q000235:genetics*; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D054731:PDZ Domains; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics / Q000378:metabolism*; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics*; D000099052:CRF Receptor, Type 1
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; C484659:PDZK1 protein, human; D034741:RNA, Small Interfering; D044402:Receptor, Serotonin, 5-HT2A; D018019:Receptors, Corticotropin-Releasing Hormone; D000099052:CRF Receptor, Type 1; D000242:Cyclic AMP; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3
keywords: Corticotrophin-releasing factor receptor 1; Mood disorders; Protein interaction; Serotonin receptor 2A; Signaling; Trafficking