NXT1 functions as a nuclear export factor in both RAN (Ras-related nuclear protein) and CRM1 (required for chromosome region maintenance) dependent pathways. It is found to stimulate the export of U1 snRNA in RAN- and CRM1-dependent pathways and the export of tRNA and mRNA in a CRM1-independent pathway. This protien heterodimerizes with Tap protein and may regulate the ability of Tap protein to mediate nuclear mRNA export.