title: Dynamic Na+-H+ exchanger regulatory factor-1 association and dissociation regulate parathyroid hormone receptor trafficking at membrane microdomains.
abstract: Na/H exchanger regulatory factor-1 (NHERF1) is a cytoplasmic PDZ (postsynaptic density 95/disc large/zona occludens) protein that assembles macromolecular complexes and determines the localization, trafficking, and signaling of select G protein-coupled receptors and other membrane-delimited proteins. The parathyroid hormone receptor (PTHR), which regulates mineral ion homeostasis and bone turnover, is a G protein-coupled receptor harboring a PDZ-binding motif that enables association with NHERF1 and tethering to the actin cytoskeleton. NHERF1 interactions with the PTHR modify its trafficking and signaling. Here, we characterized by live cell imaging the mechanism whereby NHERF1 coordinates the interactions of multiple proteins, as well as the fate of NHERF1 itself upon receptor activation. Upon PTHR stimulation, NHERF1 rapidly dissociates from the receptor and induces receptor aggregation in long lasting clusters that are enriched with the actin-binding protein ezrin and with clathrin. After NHERF1 dissociates from the PTHR, ezrin then directly interacts with the PTHR to stabilize the PTHR at the cell membrane. Recruitment of β-arrestins to the PTHR is delayed until NHERF1 dissociates from the receptor, which is then trafficked to clathrin for internalization. The ability of NHERF to interact dynamically with the PTHR and cognate adapter proteins regulates receptor trafficking and signaling in a spatially and temporally coordinated manner.
authors.affiliation: Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Ardura
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Simon C
authors.initials: SC
authors.lastname: Watkins
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Vilardaga
authors.forename: Peter A
authors.initials: PA
authors.lastname: Friedman
mesh_terms: D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004705:Endocytosis; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D006801:Humans; D008954:Models, Biological; D012516:Osteosarcoma / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013997:Time Factors; D000099149:Ezrin
chemical_list: D019393:Arrestin; D003598:Cytoskeletal Proteins; D010281:Parathyroid Hormone; D010750:Phosphoproteins; D044168:Receptor, Parathyroid Hormone, Type 1; D043562:Receptors, G-Protein-Coupled; D017923:Sodium-Hydrogen Exchangers; D000099149:Ezrin; C093376:sodium-hydrogen exchanger regulatory factor