Eukaryotic Translation Initiation Factor 4E Transporter (EIF4ENIF1)

EIF4ENIF1 is a nucleocytoplasmic shuttle protein for the translation initiation factor eIF4E. This shuttle protein interacts with the importin alpha-beta complex to mediate nuclear import of eIF4E. It is predominantly cytoplasmic;its own nuclear import is regulated by a nuclear localization signal and nuclear export signals.

The deduced 985-amino acid protein has a calculated molecular mass of 108.2 kD. EIF4ENIF1 contains a single N-terminal EIF4E-binding site, a bipartite nuclear localization signal, and 2 leucine-rich nuclear export signals. Northern blot analysis revealed a prominent 3.8-kb transcript in all tissues tested. By Western blot analysis, EIF4ENIF1 has an apparent molecular mass of about 140 kD.