|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 145, Number 4, May 17, 1999 645-657
Departments of Cell Biology and Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
We recently developed an assay in which nuclear export of the shuttling transcription factor NFAT
(nuclear factor of activated T cells) can be reconstituted in permeabilized cells with the GTPase Ran and
the nuclear export receptor CRM1. We have now used this assay to identify another export factor. After preincubation of permeabilized cells with a Ran mutant that
cannot hydrolyze GTP (RanQ69L), cytosol supports
NFAT export, but CRM1 and Ran alone do not. The
RanQ69L preincubation leads to accumulation of
CRM1 at the cytoplasmic periphery of the nuclear pore
complex (NPC) in association with the p62 complex
and Can/Nup214. RanGTP-dependent association of
CRM1 with these nucleoporins was reconstituted in
vitro. By biochemical fractionation and reconstitution,
we showed that RanBP1 restores nuclear export after
the RanQ69L preincubation. It also stimulates nuclear
export in cells that have not been preincubated with
RanQ69L. RanBP1 as well as Ran-binding domains of
the cytoplasmic nucleoporin RanBP2 promote the release of CRM1 from the NPC. Taken together, our results indicate that RanGTP is important for the targeting of export complexes to the cytoplasmic side of the
NPC and that RanBP1 and probably RanBP2 are involved in the dissociation of nuclear export complexes
from the NPC in a terminal step of transport.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
