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. 2014 Feb 20;9(2):e88887. doi: 10.1371/journal.pone.0088887

Figure 7. Model for importin 7- and Nup358-assisted import of hTERT.

Figure 7

Cytoplasmic hTERT (TERT) interacts with Nup358, the major component of the cytoplasmic filaments of the NPC (blue rods). Upon binding of importin 7, hTERT is translocated across the NPC. In the nucleus, several mechanisms could promote the dissociation of the import complex: binding of RanGTP (R•GTP), which is generated in the vicinity of chromatin-bound RCC1, to importin 7; binding of hTERT to DNA; interaction of TERC, the RNA-component of telomerase with hTERT; accessory factors (XY) that bind to hTERT. The resulting importin 7/RanGTP complex then recycles back to the cytoplasmic side of the NPC, where it is captured by the Ran-binding sites of Nup358 (two of them are shown as red boxes). Finally, Nup358-associated RanGAP promotes GTP-hydrolysis on Ran, resulting in free RanGDP (R•GDP) and importin 7, which is kept in the vicinity of the NPC to initiate a new round of import.