LATI (the 4F2-light chain I) is a component of the CD98 surface antigen which participates in multiple functions including amino acid transport, cell survival, cell fusion and integrin activation. We examined the distribution of LATI in the mouse brain using immunohistochemistry. LATI was expressed on the microvessels, the subfornical organ, the subcommissural organ, ventromedial nucleus of the hypothalamus, subgranular zone of the dentate gyrus, ependymal layer of the lateral ventricles, and the olfactory bulb. LATI-positive cells incorporated bromodeoxyuridine in the latter three regions where neurogenesis occurs in adult mouse brain, indicating that LATI is involved in neuronal cell proliferation, as well as in amino acid transport in these regions.