The neuronal adaptor protein Fe65 is phosphorylated by mitogen-activated protein kinase (ERK1/2).

Fe65 is a neuronal adaptor protein that binds a number of ligands and which functions in both gene transcription/nuclear signalling and in the regulation of cell migration and motility. These different functions within the nucleus and at the cell surface are mediated via Fe65's different binding partners. An Fe65/APP/TIP60 complex is transcriptionally active within the nucleus and an Fe65/APP/Mena complex probably regulates actin dynamics in lamellipodia. The mechanisms that regulate these different Fe65 functions are unclear. Here, we demonstrate that Fe65 is a phosphoprotein and, using mass spectrometry sequencing, identify for the first time in vivo phosphorylation sites in Fe65. We also show that Fe65 is a substrate for phosphorylation by the mitogen-activated protein kinases ERK1/2. Our results provide a mechanism by which Fe65 function may be modulated to fulfil its various roles.