Extensive identification and in-depth validation of importin 13 cargoes

Importin 13 is a bidirectional transport receptor that mediates both nuclear import and export of proteins. To expand the range of human importin 13 cargoes, we performed importin 13 binding experiments in combination with quantitative stable isotope labeling with amino acids in cell culture (SILAC) and mass spectrometry. Apart from known importin 13 interaction partners, such as Ubc9 and eIF1A, more than 300 potential importin 13 cargoes were identified, several of which could be validated using cellular and biochemical assays.