Temporal Quantitative Proteomics of mGluR-induced Protein Translation and Phosphorylation in Neurons

Mol Cell Proteomics. 2020 Dec;19(12):1952-1968. doi: 10.1074/mcp.RA120.002199. Epub 2020 Sep 10.

Abstract

At neuronal synapses, activation of group I metabotropic glutamate receptors (mGluR1/5) triggers a form of long-term depression (mGluR-LTD) that relies on new protein synthesis and the internalization of AMPA-type glutamate receptors. Dysregulation of these processes has been implicated in the development of mental disorders such as autism spectrum disorders and therefore merit a better understanding on a molecular level. Here, to study mGluR-induced signaling pathways, we integrated quantitative phosphoproteomics with the analyses of newly synthesized proteins via bio-orthogonal amino acids (azidohomoalanine) in a pulsed labeling strategy in cultured hippocampal neurons stimulated with DHPG, a specific agonist for group I mGluRs. We identified several kinases with important roles in DHPG-induced mGluR activation, which we confirmed using small molecule kinase inhibitors. Furthermore, changes in the AMPA receptor endocytosis pathway in both protein synthesis and protein phosphorylation were identified, whereby Intersectin-1 was validated as a novel player in this pathway. This study revealed several new insights into the molecular pathways downstream of group I mGluR activation in hippocampal neurons, and provides a rich resource for further analyses.

Keywords: AMPA receptor; Protein synthesis; mGluR-LTD; neurobiology; phosphoproteome; quantification; synaptic plasticity; tandem mass tags; targeted mass spectrometry; translation.

Publication types

  • Research Support, Non-U.S. Gov't