Neuroligin 1 is a synaptic cell-adhesion molecule that is enriched in postsynaptic densities where it may recruit receptors, channels, and signal-transduction molecules to synaptic sites of cell adhesion. In addition, the neuroligin/beta-neurexin junction may be involved in the excitatory/inhibitory specification of CNS neuron synapses. A role for Neuroligin 1 is also suggested in autism.