LRFN4 is a 635 amino acid single-pass type I membrane protein that belongs to the LRFN family. Containing a fibronectin type-III domain, an Ig-like (immunoglobulin-like) domain, a LRRCT domain, a LRRNT domain and seven LRR (leucine-rich) repeats, LRFN4 is thought to promote neurite outgrowth in hippocampal neurons and may play a role in redistributing PSD-95 to the cell periphery. LRFN4 forms heteromeric complexes with LRFN1, LRFN2, LFRN3 and LFRN5, but does not have the ability to form homomeric complexes across cell junctions of adjacent cells like some other LRFN family members. The PDZ-binding motif of LRFN4 is required for neurite outgrowth promotion and for SAP 97-, NE-dlg- and PSD-95-binding. LRFN4 is encoded by a gene located on human chromosome 11q13.1 and mouse chromosome 19 A.