A novel mechanism of hippocampal LTD involving muscarinic receptor-triggered interactions between AMPARs, GRIP and liprin-alpha

作者：Dickinson Bryony A; Jo Jihoon; Seok Heon; Son Gi Hoon; Whitcomb Daniel J; Davies Ceri H; Sheng Morgan; Collingridge Graham L; Cho Kwangwook^*

来源：Molecular Brain, 2009, 2(1): 18.

DOI：10.1186/1756-6606-2-18

Background: Long-term depression (LTD) in the hippocampus can be induced by activation of different types of G-protein coupled receptors, in particular metabotropic glutamate receptors (mGluRs) and muscarinic acethycholine receptors (mAChRs). Since mGluRs and mAChRs activate the same G-proteins and isoforms of phospholipase C (PLC), it would be expected that these two forms of LTD utilise the same molecular mechanisms. However, we find a distinct mechanism of LTD involving GRIP and liprin-alpha.
Results: Whilst both forms of LTD require activation of tyrosine phosphatases and involve internalisation of AMPARs, they use different molecular interactions. Specifically, mAChR-LTD, but not mGluR-LTD, is blocked by peptides that inhibit the binding of GRIP to the AMPA receptor subunit GluA2 and the binding of GRIP to liprin-alpha. Thus, different receptors that utilise the same G-proteins can regulate AMPAR trafficking and synaptic efficacy via distinct molecular mechanisms.
Conclusion: Our results suggest that mAChR-LTD selectively involves interactions between GRIP and liprin-alpha. These data indicate a novel mechanism of synaptic plasticity in which activation of M1 receptors results in AMPAR endocytosis, via a mechanism involving interactions between GluA2, GRIP and liprin-alpha.

• 出版日期2009