Translational control of mGluR-dependent long-term depression and object-place learning by eIF2a
Gonzalo Viana Di Prisco, etc
Nature Neuroscience, 2014
At hippocampal synapses, activation of group I metabotropic glutamate receptors (mGluRs) induces long-term depression (LTD), which requires new protein synthesis. However, the underlying mechanism remains elusive. Here we describe the translational program that underlies mGluR-LTD and identify the translation factor eIF2a as its master effector. Genetically reducing eIF2a phosphorylation, or specifically blocking the translation controlled by eIF2a phosphorylation, prevented mGluR-LTD and the internalization of surface AMPA receptors (AMPARs). Conversely, direct phosphorylation of eIF2a, bypassing mGluR activation, triggered a sustained LTD and removal of surface AMPARs. Combining polysome profiling and RNA sequencing, we identified the mRNAs translationally upregulated during mGluR-LTD. Translation of one of these mRNAs, oligophrenin-1, mediates the LTD induced by eIF2a phosphorylation. Mice deficient in phospho-eIF2a–mediated translation are impaired in object-place learning, a behavioral task that induces hippocampal mGluR-LTD in vivo. Our findings identify a new model of mGluR-LTD, which promises to be of value in the treatment of mGluR-LTD-linked cognitive disorders.