Leucine Rich Repeat LGI Family, Member 4 (LGI4)

The deduced 538-amino acid protein contains an 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. LGI4 shares significant similarity with LGI1, LGI2, and LGI3. Semiquantitative PCR detected LGI4 expression in all tissues examined, with highest expression in brain.

Lgi4 was expressed at high levels in the rostral migratory stream and the Purkinje cell layer of the cerebellar cortex. Lgi4 was secreted in transfected 293T cells. Immunofluorescence microscopy localized Lgi4 to discrete intracellular compartments, consistent with its presence in ER, Golgi bodies, and vesicles.