Quantitative phosphoproteomics reveals the protein tyrosine kinase Pyk2 as a central effector of olfactory receptor signaling in prostate cancer cells

Biochim Biophys Acta. 2015 Jun;1854(6):632-40. doi: 10.1016/j.bbapap.2014.09.002. Epub 2014 Sep 9.


The prostate-specific G-protein-coupled receptor 1 (PSGR1) is an olfactory receptor specifically expressed in the prostate gland. PSGR1 expression is elevated both in benign prostatic hyperplasia tissue and in prostate cancer. Stimulation of PSGR1 by the odorant β-ionone leads to an increase in the intracellular Ca(2+) concentration, activation of mitogen-activated protein (MAP) kinases and a decrease in prostate cancer cell proliferation. To further extend our knowledge about PSGR1 signaling in prostate cancer cells, we performed a quantitative phosphoproteomics study using stable isotope labeling by amino acids in cell culture and mass spectrometry. We report 51 differentially regulated phosphorylation sites in 24 proteins with functions in cytoskeletal remodeling, signaling and ion transport. Activation of PSGR1 evoked an increase in intracellular pH mediated by the sodium/hydrogen exchanger NHE1. Furthermore, we report the protein tyrosine kinase Pyk2 as a central effector of PSGR1 signaling cascades in LNCaP cells. Our data show that phosphorylation of p38 MAP kinase is triggered by Pyk2. In addition, we confirmed dephosphorylation of the tumor suppressor protein N-myc downstream regulated gene 1 (NDRG1) at Ser330 downstream of Pyk2. Since NDRG1 impacts oncogenic signaling pathways interfering with tumor progression, we suggest that the Pyk2-NDRG1 axis is possibly involved in conveying the anti-proliferative effect of β-ionone in prostate cancer cells. This article is part of a Special Issue entitled: Medical Proteomics.

Keywords: Olfactory receptor; Phosphoproteomics; Prostate cancer cell; Quantitative mass spectrometry; SILAC; Signal transduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Focal Adhesion Kinase 2 / genetics
  • Focal Adhesion Kinase 2 / metabolism*
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • MAP Kinase Signaling System*
  • Male
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Norisoprenoids / pharmacology
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Phosphorylation / drug effects
  • Phosphorylation / genetics
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism*
  • Receptors, Odorant / genetics
  • Receptors, Odorant / metabolism*
  • p38 Mitogen-Activated Protein Kinases / genetics
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Cell Cycle Proteins
  • Intracellular Signaling Peptides and Proteins
  • N-myc downstream-regulated gene 1 protein
  • Neoplasm Proteins
  • Norisoprenoids
  • OR51E2 protein, human
  • Phosphoproteins
  • Receptors, Odorant
  • beta-ionone
  • Focal Adhesion Kinase 2
  • p38 Mitogen-Activated Protein Kinases