Homer interactions are necessary for metabotropic glutamate receptor-induced long-term depression and translational activation

Jennifer A. Ronesi, Kimberly M. Huber

Research output: Contribution to journalArticle

181 Citations (Scopus)

Abstract

Group I metabotropic glutamate receptors (mGluRs) induce a form of long-term synaptic depression (mGluR-LTD) in area CA1 of the hippocampus that requires rapid protein synthesis. Althoughmuchisknownabout the mechanisms underlying mGluR-LTD, it is unclear how mGluRs couple to the effectors necessary for translation initiation. A clue comes from work in the mouse model of Fragile X syndrome [Fmr1 knock-out (KO) mice], where group 1 mGluR stimulation of protein synthesis is absent and mGluRs are less associated with the postsynaptic scaffolding protein Homer (Giuffrida et al., 2005). Here, we examined the role of Homer interactions in mGluR-LTD and mGluR signaling to protein synthesis machinery in wild-type and Fmr1 KO animals. A peptide that mimics the C-terminal tail of mGluR5 (mGluR5ct), shown previously to disrupt Homer interactions with mGluRs, blocks mGluR-LTD and mGluR-signaling to protein synthesis initiation in wild-type animals. Disruption of mGluR-Homer interactions selectively blocks mGluR activation of the phosphoinositide 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR), but not ERK (extracellular signal-regulated kinase), pathway and translation of a 5′ terminal oligopyrimidine tract containing mRNA, Elongation factor 1α. In Fmr1 KO mice, mGluR-LTD is insensitive to disruption of Homer interactions and mGluR activation of PI3K-mTOR is lost. Our results find specific roles for Homer in mGluR signaling and plasticity and suggest that reduced mGluR-Homer interactions in Fmr1 KO mice lead to a deficit in mGluR stimulation of translation initiation.

Original languageEnglish (US)
Pages (from-to)543-547
Number of pages5
JournalJournal of Neuroscience
Volume28
Issue number2
DOIs
StatePublished - Jan 9 2008

Fingerprint

Metabotropic Glutamate Receptors
Knockout Mice
1-Phosphatidylinositol 4-Kinase
Sirolimus
Proteins
Long-Term Synaptic Depression
Peptide Elongation Factor 1
Fragile X Syndrome
Wild Animals
Extracellular Signal-Regulated MAP Kinases
Tail
Hippocampus
Messenger RNA

Keywords

  • Fragile X
  • Group I mGluRs
  • Homer
  • Long-term depression
  • mTOR
  • PI3K
  • Translation

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Homer interactions are necessary for metabotropic glutamate receptor-induced long-term depression and translational activation. / Ronesi, Jennifer A.; Huber, Kimberly M.

In: Journal of Neuroscience, Vol. 28, No. 2, 09.01.2008, p. 543-547.

Research output: Contribution to journalArticle

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