Shipman_2012_Neuron_76_309

At neuronal excitatory synapses two major subtypes of the synaptic adhesion molecule neuroligin are present These subtypes neuroligin 1 and neuroligin 3 have roles in synaptogenesis and synaptic maintenance that appear largely overlapping In this study we combine electrophysiology with molecular deletion and replacement of these proteins to identify similarities and differences between these subtypes In doing so we identify a subtype-specific role in LTP for neuroligin 1 in young CA1 which persists into adulthood in the dentate gyrus As neuroligin 3 showed no requirement for LTP we constructed chimeric proteins of the two excitatory neuroligin subtypes to identify the molecular determinants particular to the unique function of neuroligin 1 Using in vivo molecular replacement experiments we find that these unique functions depend on a region in its extracellular domain containing the B site splice insertion previously shown to determine specificity of neurexin binding.