LRRN1 (Leucine-rich repeat neuronal protein 1; NLRR1) is a 95 kDa member of the neuronal LRR family of proteins. It is a cell-surface glycoprotein that is expressed on embryonic motor neurons and somatic myoblasts. Human LRRN1 is 716 amino acids (aa) in length. It is a type I transmembrane protein that contains a 606 aa extracellular region (aa 26 - 631) and a short 64 aa cytoplasmic tail. The extracellular region shows eleven LRRs (aa 94 - 384) that mediate protein-protein interactions, one C2-type Ig-like domain and one fibronectin type III domain. There is one potential alternate start site at Met286. Over aa 26 - 631, human LRRN1 shares 96% aa identity with mouse LRRN1.