The deduced 549-amino acid protein contains a N-terminal signal peptide, a putative transmembrane region, and 1 partial and 4 complete leucine-rich repeats (LRRs). The LRRs are flanked on both sides by cysteine-rich regions, and the N-terminal cysteine-rich region contains a motif conserved in LGIs. LGI3 shares significant similarity with LGI1, LGI2, and LGI4. Semiquantitative PCR detected LGI3 expression in all tissues examined, with highest levels in brain and lung.
By in situ hybridization of adult mouse brain, Senechal et al. (2005) showed that Lgi3 was expressed at low levels in most brain regions with high levels in the facial nerve nucleus. Lgi3 was secreted in transfected 293T cells.