Identification of proteins locally synthesized at the synapse in response to neuronal stimulation in physiology and fragile X syndrome

In the proposed project we will use synaproneurosomes isolated from wild type and Fmr1KO mice brains to study the process of local protein translation and stimulate them in vitro to induce polysomal assembly and protein synthesis. Two stimulation protocols were chosen to recapitulate long-term potentiation (LTP) and long-term depression (LTD) induction: first will be the activation of NMDA-type glutamate receptors that induces LTP in many brain regions. The second will be the application of DHPG, an agonist of group I metabotropic glutamate receptors (mGluRs) which produces LTD (DHPG-LTD). Remarkably, both of these opposing changes in synaptic efficacy require dendritic protein synthesis. We will apply the incorporation of labeled amino acid L-homopropargylglycine (HPG) combined with mass spectrometry to detect nascent protein synthesis in stimulated synaptoneurosomes. Next, we will confirm the synaptic translation of the selected proteins and study their synaptic functions.