A Combined Transgenic Proteomic Analysis and Regulated Trafficking of Neuroligin-2

Abstract

Background: Brain inhibitory synaptic connections present challenges for molecular identification and imaging. Results: Transgenic mice expressing tagged neuroligin-2 were used to identify associated complexes and image inhibitory synapses in multiple brain regions. Conclusion: Neuroligin-2-associated complexes are enriched in synaptic components, and neuroligin-2 undergoes regulated dynamin-dependent endocytosis and retromer association. Significance: New data and approaches are presented for brain inhibitory synapse proteomics and imaging.

Proteomic Analysis of Unbounded Cellular Compartments: Synaptic Clefts

“…Our inhibitory synapse proteome can also be compared to two previous studies that use immunoprecipitation-MS, rather than biochemical fractionation, to identify components of the GABAergic synapse (Heller et al, 2012; Kang et al, 2014). Though the Heller et al study that uses GABA A receptor α1 immunoprecipitation is quite specific, both datasets miss the majority of known inhibitory synaptic cleft components (coverage <34%), probably because the baits used do not interact directly or stably with these proteins.…”

The balancing act of GABAergic synapse organizers

“…Unlike the extensive information now available on excitatory synapse proteins, our understanding of inhibitory synapse organization remains limited [6,7]. An obstacle to this goal is the need to determine how synaptic-and circuitlevel inhibition is achieved by diverse interneurons that display distinct morphologies, physiological properties, connectivity patterns, and gene expression profiles.…”

Gephyrin: a central GABAergic synapse organizer

“…99 In addition, NL-2, but not other neuroligin paralogs, has been shown to directly interact with gephyrin through a conserved tyrosine residue (Tyr770) that helps recruit gephyrin to NL-2 clusters in cultured neurons. 76,100 Moreover, NL-2 activates the collybistin-mediated targeting of gephyrin to the plasma membrane in non-neuronal cells. Intriguingly, NL-2 was found to be required for gephyrin to be recruited to the perisomatic site but not to the dendritic shaft.…”