The leucine-rich (LRR) repeat is a 20-30 amino acid motif that forms a hydrophobic å/∫ horseshoe fold, allowing it to accommodate several leucine residues within a tightly packed core. All LRR repeats contain a variable segment and a highly conserved segment, the latter of which accounts for 11 or 12 residues of the entire LRR motif. FLRT1 (fibronectin leucine rich transmembrane protein 1) is a 646 amino acid single-pass type I membrane protein that contains one fibronectin type-III domain and ten LRR repeats. Expressed in kidney and brain, FLRT1 is thought to play a role in cell adhesion and receptor signaling. FLRT1 shares similarity with FLRT2 and FLRT3 and is subject to post-translational N-glycosylation. The gene encoding FLRT1 maps to human chromosome 11, which houses over 1,400 genes and comprises nearly 4% of the human genome.