Neuronal adhesion molecule that is required for normal migration of young postmitotic neuroblasts along glial fibers, especially in the cerebellum. Required for normal rate of migration of granule cells during brain development and for normal cerebellum development. Interacts with ASTN2; the interaction is not calcium-dependent. Detected close to the anterior pole and at the base of the leading process in migrating neurons. Is internalized from the membrane via clathrin-coated vesicles and endosomes, and recycled to the anterior pole of the migrating cell. Detected in brain (at protein level) (PubMed:11861479). Expressed specifically in the brain. Expressed in the cerebellum, hippocampus, cerebrum and olfactory bulb (PubMed:8602532). First detected in embryonic brain at 12 dpc. Expression increases thereafter, is highest in brain from pups 4 days after birth, and then decreases again. Expression is decreased 14 days after birth, and not detectable in adult brain. Slower than normal migration of granule cells in the developing cerebellum, leading to a decreased cerebellum size in adult mice and impaired skills in tasks that require coordinated movement and balance. Granule cells from mutant mice have a rounded shape and lack the elongated shape seen in wild-type. At 6 days after birth, increased granule cell apoptosis is observed, contrary to the situation in wild-type. Belongs to the astrotactin family.