Exportin-mediated nuclear export of proteins and ribonucleoproteins.

Protein export from the nucleus of eukaryotic cells serves three main purposes: (1) to remove factors that are only transiently required in the nucleus — transcriptional signaling molecules fall into this category; (2) to participate in RNA export — all RNAs that leave the nucleus, do so in complex with proteins; (3) to recycle import factors that have been dissociated from their cargoes and have to return to the cytoplasm for a further round. A fourth conceivable function is to remove proteins that have unintentionally entered the nucleus, e.g. by diffusion or by inclusion into a reforming nucleus after mitosis.