(Macara 2001)

Purposes of Nuclear Export of Proteins:

1.  Remove factors needed only at specific times from the nucleus

2.  Recycle the import factors after they have dissociated from the proteins that they were carrying.

Requirements for Nuclear Export:

1.  Signal on protein to be exported (NES)

2.  export receptor (exportin)

3.  in some cases, an adapter molecule is needed to mediate the interaction between the exportin and cargo protein

(Macara 2001)

Process of Nuclear Export:

First, a cargo protein, exportin, and RanGTP undergo cooperative binding to form a complex.

This complex is then transported through the nuclear pore complex.  Transport is mediated by interactions between the exportin and nucleoporins that contain FG repeats.

When the complex reaches the cytosolic side of the NPC, the cargo and exportin are released as RanGTP is hydrolyzed to RanGDP by RanGAP.

(Ossareh-Nazari et al. 2001)