Phosphotyrosine profiling in brain tissue: a methodology to study the impact of growth factors signaling
C. A. CAAMANO; C. TURNER; E. SIMON; P. ANDREWS; H. AKIL
Society for Neuroscience. 2007.
The fibroblast growth factor (FGF) system is altered in post-mortem brains of individuals with major depressive disorder (MDD). Specifically, the mRNA expression for several ligands (i.e., FGF1, FGF2) and receptors (i.e., FGFR2, FGFR3) were found downregulated in different brain areas, including hippocampus and dorsolateral prefrontal cortex. More recently, pointing to the functional significance of the FGF system, our lab has shown that the modulation of the FGF tone in a rodent model has antidepressant-like effects. The aim of this study was to understand the action of FGF2 at the signaling level. Provided FGF receptors are prototypic receptor tyrosine kinases, we have followed a mass spectrometry approach to identify the tyrosine-phosphorylated proteins induced in brain tissue by intracerebroventricular injection of FGF2 ligand. Upon trypsin digestion, peptides containing phosphotyrosine were isolated by immunoadsorption with a phosphotyrosine-specific antibody and identified by tandem mass spectrometry. Relative phosphopeptide quantification was performed by isobaric labeling. The identified regulated protein kinases and their substrates are being used to build FGF-relevant signaling networks.