CD171/L1CAM

CD171, the L1 cell adhesion molecule, is a neuronal member of the L1 branch of the immunoglobulin superfamily alongside NCAM, neurofascin and NrCAM. Its extracellular region combines six Ig-like domains and five fibronectin type III repeats that mediate both homophilic and heterophilic adhesion with partners including integrins. L1CAM guides axon outgrowth and fasciculation during neural development, and mutations in its X-linked gene cause the spectrum of CRASH syndromes encompassing corpus callosum hypoplasia, hydrocephalus and spastic paraplegia. Aberrant re-expression in endometrial, ovarian and pancreatic carcinomas promotes invasion, and CD171 is being developed as a therapeutic target with antibody and CAR-T approaches.