Probable ligand for integrin in the brain. This is a non catalytic metalloprotease-like protein. Involved in regulation of cell adhesion and spreading and in inhibition of cell proliferation (By similarity). Neuronal receptor for LGI1. Interacts with LGI1 (PubMed:18974846, PubMed:20089912). Can bind to LGI4(PubMed:18974846). Interacts with KCNA2, DLG2 and DLG4 (PubMed:20089912). Detected in juxtaparanodal zones in the central nervous system and at nerve terminal plexuses of basket cells in the cerebellum (at protein level) (PubMed:20089912). Expressed at high levels in the brain. Strongly expressed in cerebellar granule cells and hippocampus. In spinal cord, expression is restricted to gray matter. The precursor is cleaved by a furin endopeptidase. Mice display severe ataxia within one week after birth and die before weaning, probably due to convulsions. They display marked hypomyelination of the peripheral nerves.