What is the mechanism for nuclear transport?
Background and Significance
The nuclear envelope establishes an essential regulatory barrier by which eukaryotic cells can
control access to the nuclear genome. Gene regulatory signals are transduced into the nucleus
through the import of specific regulatory proteins. Many of these nuclear proteins contain a
"classical" nuclear localization signal (NLS). Extensive study of this nuclear transport
pathway has identified a number of component proteins essential for efficient import of the NLSsubstrate
into the nucleus. A heterodimeric nuclear transport receptor (importin a/importin b)
and Ran were originally identified using an in vitro permeabilized cell system. They were shown
to be essential for nuclear import of NLS-substrate . ...