Activity-Dependent Validation of Excitatory versus Inhibitory Synapses by Neuroligin-1 versus Neuroligin-2

Alexander A. Chubykin, Deniz Atasoy, Mark R. Etherton, Nils Brose, Ege T. Kavalali, Jay R. Gibson, Thomas C. Südhof

Research output: Contribution to journalArticlepeer-review

463 Scopus citations

Abstract

Neuroligins enhance synapse formation in vitro, but surprisingly are not required for the generation of synapses in vivo. We now show that in cultured neurons, neuroligin-1 overexpression increases excitatory, but not inhibitory, synaptic responses, and potentiates synaptic NMDAR/AMPAR ratios. In contrast, neuroligin-2 overexpression increases inhibitory, but not excitatory, synaptic responses. Accordingly, deletion of neuroligin-1 in knockout mice selectively decreases the NMDAR/AMPAR ratio, whereas deletion of neuroligin-2 selectively decreases inhibitory synaptic responses. Strikingly, chronic inhibition of NMDARs or CaM-Kinase II, which signals downstream of NMDARs, suppresses the synapse-boosting activity of neuroligin-1, whereas chronic inhibition of general synaptic activity suppresses the synapse-boosting activity of neuroligin-2. Taken together, these data indicate that neuroligins do not establish, but specify and validate, synapses via an activity-dependent mechanism, with different neuroligins acting on distinct types of synapses. This hypothesis reconciles the overexpression and knockout phenotypes and suggests that neuroligins contribute to the use-dependent formation of neural circuits.

Original languageEnglish (US)
Pages (from-to)919-931
Number of pages13
JournalNeuron
Volume54
Issue number6
DOIs
StatePublished - Jun 21 2007

Keywords

  • MOLNEURO
  • SIGNALING

ASJC Scopus subject areas

  • General Neuroscience

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