RanBP3 influences interactions between CRM1 and its nuclear protein export substrates.
We investigated the role of RanBP3, a nuclear member of the Ran-binding protein 1 family, in CRM1-mediated protein export in higher eukaryotes. RanBP3 interacts directly with CRM1 and also forms a trimeric complex with CRM1 and RanGTP. However, RanBP3 does not bind to CRM1 like an export substrate. Instead, it can stabilize CRM1-export substrate interaction. Nuclear RanBP3 stimulates CRM1-dependent protein export in permeabilized cells. These data indicate that RanBP3 functions by a novel mechanism as a cofactor in recognition and export of certain CRM1 substrates. In vitro, RanBP3 binding to CRM1 affects the relative affinity of CRM1 for different substrates.
Englmeier
L
L
European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
Fornerod
M
M
Bischoff
F R
FR
Petosa
C
C
Mattaj
I W
IW
Kutay
U
U
D002352:Carrier Proteins / Q000378:metabolism* / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D020558:GTP Phosphohydrolases / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D009687:Nuclear Proteins / Q000378:metabolism* / Q000502:physiology*; D029543:Nucleocytoplasmic Transport Proteins; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D018160:Receptors, Cytoplasmic and Nuclear; D013379:Substrate Specificity; D013997:Time Factors; D020931:ran GTP-Binding Protein / Q000378:metabolism; D000097606:Exportin 1 Protein
D002352:Carrier Proteins; D020558:GTP Phosphohydrolases; D005982:Glutathione Transferase; D028884:Karyopherins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D020931:ran GTP-Binding Protein; D000097606:Exportin 1 Protein; C112820:RANBP3 protein, human