PDZK1/NHERF3 differentially regulates corticotropin-releasing factor receptor 1 and serotonin 2A receptor signaling and endocytosis

Cell Signal. 2015 Mar;27(3):519-31. doi: 10.1016/j.cellsig.2014.12.019. Epub 2015 Jan 3.


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.

Keywords: Corticotrophin-releasing factor receptor 1; Mood disorders; Protein interaction; Serotonin receptor 2A; Signaling; Trafficking.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / antagonists & inhibitors
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Membrane / metabolism
  • Cyclic AMP / metabolism
  • Endocytosis / genetics*
  • HEK293 Cells
  • Humans
  • Membrane Proteins
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • PDZ Domains
  • Phosphorylation
  • Protein Interaction Domains and Motifs
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Receptor, Serotonin, 5-HT2A / genetics
  • Receptor, Serotonin, 5-HT2A / metabolism*
  • Receptors, Corticotropin-Releasing Hormone / genetics
  • Receptors, Corticotropin-Releasing Hormone / metabolism*
  • Signal Transduction / genetics*


  • Carrier Proteins
  • Membrane Proteins
  • PDZK1 protein, human
  • RNA, Small Interfering
  • Receptor, Serotonin, 5-HT2A
  • Receptors, Corticotropin-Releasing Hormone
  • CRF receptor type 1
  • Cyclic AMP
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3