Formation of a ternary complex among NHERF1, beta-arrestin, and parathyroid hormone receptor

J Biol Chem. 2010 Sep 24;285(39):30355-62. doi: 10.1074/jbc.M110.114900. Epub 2010 Jul 23.

Abstract

β-Arrestins are crucial regulators of G-protein coupled receptor (GPCR) signaling, desensitization, and internalization. Despite the long-standing paradigm that agonist-promoted receptor phosphorylation is required for β-arrestin2 recruitment, emerging evidence suggests that phosphorylation-independent mechanisms play a role in β-arrestin2 recruitment by GPCRs. Several PDZ proteins are known to interact with GPCRs and serve as cytosolic adaptors to modulate receptor signaling and trafficking. Na(+)/H(+) exchange regulatory factors (NHERFs) exert a major role in GPCR signaling. By combining imaging and biochemical and biophysical methods we investigated the interplay among NHERF1, β-arrestin2, and the parathyroid hormone receptor type 1 (PTHR). We show that NHERF1 and β-arrestin2 can independently bind to the PTHR and form a ternary complex in cultured human embryonic kidney cells and Chinese hamster ovary cells. Although NHERF1 interacts constitutively with the PTHR, β-arrestin2 binding is promoted by receptor activation. NHERF1 interacts directly with β-arrestin2 without using the PTHR as an interface. Fluorescence resonance energy transfer studies revealed that the kinetics of PTHR and β-arrestin2 interactions were modulated by NHERF1. These findings suggest a model in which NHERF1 may serve as an adaptor, bringing β-arrestin2 into close proximity to the PTHR, thereby facilitating β-arrestin2 recruitment after receptor activation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Arrestins / genetics
  • Arrestins / metabolism*
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Humans
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Protein Structure, Quaternary
  • Receptor, Parathyroid Hormone, Type 1 / genetics
  • Receptor, Parathyroid Hormone, Type 1 / metabolism*
  • Signal Transduction / physiology
  • Sodium-Hydrogen Exchangers / genetics
  • Sodium-Hydrogen Exchangers / metabolism*
  • beta-Arrestins

Substances

  • Arrestins
  • Multiprotein Complexes
  • PTH1R protein, human
  • Phosphoproteins
  • Receptor, Parathyroid Hormone, Type 1
  • Sodium-Hydrogen Exchangers
  • beta-Arrestins
  • sodium-hydrogen exchanger regulatory factor