Perisomatic GABAergic synapses onto hippocampal pyramidal cells arise from two 
populations of basket cells with different neurochemical and functional 
properties. The presence of the dystrophin-glycoprotein complex in their 
postsynaptic density (PSD) distinguishes perisomatic synapses from GABAergic 
synapses on dendrites and the axon-initial segment. Targeted deletion of 
neuroligin 2 (NL2), a transmembrane protein interacting with presynaptic 
neurexin, has been reported to disrupt postsynaptic clustering of GABAA 
receptors (GABAAR) and their anchoring protein, gephyrin, at perisomatic 
synapses. In contrast, targeted deletion of Gabra2 disrupts perisomatic 
clustering of gephyrin, but not of α1-GABAAR, NL2, or dystrophin/dystroglycan. 
Unexpectedly, conditional deletion of Dag1, encoding dystroglycan, selectively 
prevents the formation of perisomatic GABAergic synapses from basket cells 
expressing cholecystokinin. Collectively, these observations suggest that 
multiple mechanisms regulate formation and molecular composition of the 
GABAergic PSD at perisomatic synapses. Here, we further explored this issue by 
investigating the effect of targeted deletion of Gabra1 and NL2 on the 
dystrophin-glycoprotein complex and on perisomatic synapse formation, using 
immunofluorescence analysis with a battery of GABAergic pre- and postsynaptic 
markers. We show that the absence of α1-GABAAR increases GABAergic synapses 
containing the α2 subunit, without affecting the clustering of dystrophin and 
NL2; in contrast, the absence of NL2 produces highly variable effects 
postsynaptically, not restricted to perisomatic synapses and being more severe 
for the GABAAR subunits and gephyrin than dystrophin. Altogether, the results 
confirm the importance of NL2 as organizer of the GABAergic PSD and unravel 
distinct roles for α1- and α2-GABAARs in the formation of GABAergic circuits in 
close interaction with the dystrophin-glycoprotein complex.