Fig. 1. Identification of potential Imp13-specific transport substrates. Immobilized Imp13 was used to fish interacting proteins from a cytosolic HeLa extract. Binding was performed in the absence or presence of RanQ69L GTP (5 µM) to identify potential import or export substrates, respectively. Bound proteins were separated by SDS–PAGE, visualized by Coomassie staining, digested with trypsin and finally identified by peptide sequencing and mass spectrometry. The following proteins were identified: RL5, ribosomal protein L5 (accession No. P46777); RBM8 (Y14), RNA-binding motif protein 8 (AAF37551); NF-YB-like protein (AAF67146); hUBC9 (AAH00427); MGN, Mago Nashi protein homologue (P50606); NPAP, nuclear pore-associated protein (AAD53401); eIF1A, eukaryotic translation initiation factor 1A (P47813).