PSD-95 regulates CRFR1 localization, trafficking and β-arrestin2 recruitment

Cell Signal. 2016 May;28(5):531-540. doi: 10.1016/j.cellsig.2016.02.013. Epub 2016 Feb 17.


Corticotropin-releasing factor (CRF) is a neuropeptide commonly associated with the hypothalamic-pituitary adrenal axis stress response. Upon release, CRF activates two G protein-coupled receptors (GPCRs): CRF receptor 1 (CRFR1) and CRF receptor 2 (CRFR2). Although both receptors contribute to mood regulation, CRFR1 antagonists have demonstrated anxiolytic and antidepressant-like properties that may be exploited in the generation of new pharmacological interventions for mental illnesses. Previous studies have demonstrated CRFR1 capable of heterologously sensitizing serotonin 2A receptor (5-HT2AR) signaling: another GPCR implicated in psychiatric disease. Interestingly, this phenomenon was dependent on Postsynaptic density 95 (PSD-95)/Disc Large/Zona Occludens (PDZ) interactions on the distal carboxyl termini of both receptors. In the current study, we demonstrate that endogenous PSD-95 can be co-immunoprecipitated with CRFR1 from cortical brain homogenate, and this interaction appears to be primarily via the PDZ-binding motif. Additionally, PSD-95 colocalizes with CRFR1 within the dendritic projections of cultured mouse neurons in a PDZ-binding motif-dependent manner. In HEK 293 cells, PSD-95 overexpression inhibited CRFR1 endocytosis, whereas PSD-95 shRNA knockdown enhanced CRFR1 endocytosis. Although PSD-95 does not appear to play a significant role in CRF-mediated cAMP or ERK1/2 signaling, PSD-95 was demonstrated to suppress β-arrestin2 recruitment: providing a potential mechanism for PSD-95's inhibition of endocytosis. In revisiting previously documented heterologous sensitization, PSD-95 shRNA knockdown did not prevent CRFR1-mediated enhancement of 5-HT2AR signaling. In conclusion, we have identified and characterized a novel functional relationship between CRFR1 and PSD-95 that may have implications in the design of new treatment strategies for mental illness.

Keywords: Arrestin; CRFR1; GPCR; PDZ; PSD-95; Trafficking.

MeSH terms

  • Animals
  • Cells, Cultured
  • Cyclic AMP / metabolism
  • Disks Large Homolog 4 Protein
  • Endocytosis
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Guanylate Kinases / metabolism*
  • HEK293 Cells
  • Humans
  • Membrane Proteins / metabolism*
  • Mice
  • Post-Synaptic Density / metabolism
  • Protein Interaction Domains and Motifs
  • Protein Transport
  • Receptors, Corticotropin-Releasing Hormone / chemistry
  • Receptors, Corticotropin-Releasing Hormone / metabolism*
  • Signal Transduction
  • beta-Arrestin 2 / metabolism*


  • Disks Large Homolog 4 Protein
  • Dlg4 protein, mouse
  • Membrane Proteins
  • Receptors, Corticotropin-Releasing Hormone
  • beta-Arrestin 2
  • CRF receptor type 1
  • Cyclic AMP
  • Extracellular Signal-Regulated MAP Kinases
  • Guanylate Kinases