FLRT3 is a 649 amino acid single-pass type I membrane protein that contains one fibronectin type-III domain and ten leucine-rich repeats and belongs to the fibronectin leucine rich transmembrane protein (FLRT) family. Expressed in heart, liver, lung, kidney, pancreas, brain, placenta and skeletal muscle, FLRT3 is thought to be involved in receptor signaling events and may play a role in both cell adhesion neurite outgrowth. Defects in the gene encoding mouse FLRT3 may lead to ventral closure, headfold fusion and endoderm migration defects, suggesting that FLRT3 is important for proper cell differentiation and development. FLRT3 exists as multiple alternatively spliced isoforms that are encoded by a gene which maps to human chromosome 20.