nuclear export complex

Function

• nuclear export of:
  • proteins with nuclear export signal (cargo)
  • RNAs (cargo)

Structure

• subunits: KPNB1, Ran, SNUPN & exportin (XPO1, XPO5) Mechanism:
• exportin & Ran-binding protein bind cooperatively to nuclear export signal on target protein & to GTPase Ran (GTP-bound)
• docking of complex to nuclear pore complex mediated via binding to nucleoporins
• transit into cytoplasm
• disassembling of complex, hydrolysis of Ran-GTP to Ran-GDP
• release of the cargo from the export receptor
• directionality of nuclear export derives from asymmetric distribution of GTP- & GDP-bound forms of Ran between cytoplasm & nucleus

Pathology

• nuclear export of
  • Rev protein of HIV-1
  • Rex protein of HTLV-1
  • adenovirus VA1 dsRNA

More general terms

• molecular complex
• nuclear protein