Export adapter involved in spliced and unspliced mRNA nuclear export. Binds mRNA which is transferred to the NXF1-NXT1 heterodimer for export (TAP/NFX1 pathway); enhances NXF1-NXT1 RNA-binding activity. Interacts (via N-terminus and RRM domain) with DDX39B and th NXF1-NXT1 heterodimer. Interacts with HHV-1 ICP27 and HVS ORF57 proteins. The RRM domain and the N-terminal region (15-58) seem to be involved in RNA binding. Arginine methylation reduces RNA binding and enhances mRNA transfer to the NXF1-NXT1 heterodimer for nuclear export.