Promotes neurite outgrowth in hippocampal neurons. Enhances the cell surface expression of 2 NMDA receptor subunits GRIN1 and GRIN2A. May play a role in redistributing DLG4 to the cell periphery (By similarity). Forms heteromeric complexes with LRFN1, LRFN3, LRFN4 and LRFN5. Can form homomeric complexes, but not across cell junctions. Directly interacts with 2 NMDA receptor subunits GRIN1 and GRIN2A (By similarity). Interacts with DLG1, DLG2, DLG3 and DLG4. The PDZ-binding motif is required for cell surface expression, neurite outgrowth promotion (By similarity). This motif is also involved in DLG1-, DLG3- and DLG4-binding. Glycosylated. Belongs to the LRFN family. Extended N-terminus.