There have been three major advances in the understanding of the Ran pathwa
y during the past two years: first, a general model for Ran's function in n
uclear transport has been proposed and extensively tested. Second, crystal
structures for many proteins that regulate or interact with Ran have been r
eported, which provide molecular details of how Ran works. Third, it has be
en documented that Ran regulates mitotic spindle assembly in a transport-in
dependent fashion.