Involved in synaptic inhibition in the brain. Selectively regulates inhibitory presynaptic differentiation through interacting with presynaptic NRXN2. Interacts (Ig-like 1 domain) with NRXN2 (via Laminin G-like 1 domain) in a trans-interaction manner. Expressed in brain (at protein levels) (PubMed:28864826). Highly expressed in the pyramidal cell layer of the dorsal and ventral hippocampal CA1 and CA3 regions, layers 5 and 6 of the cortex, the thalamus and the pons and weakly expressed in the cerebellum (PubMed:28864826). Expressed in neurons but not in glia (PubMed:28864826). Expressed in the brain at both embryonic and postnatal stages including the adult stage. The period of highest expression of the long isoform is at around two postnatal weeks, coinciding with the peak period of synaptogenesis. Ig-like 1 domain is indispensable for synaptogenic activity whereas Ig-like 2 domain is secondarily responsible for the activity. Mutants grow normally. They show an impaired sensorimotor gating with no effect on motor activity and coordination.