The control of gene expression by regulated nuclear transport.

Many proteins show distinct nuclear- and cytoplasmic-localization patterns. For proteins above the diffusion limit of the NPC, this localization is governed by the activity of NLSs and/or NESs contained in the protein. Structural modification of proteins can affect NLS and NES activities. Ligand binding, phosphorylation and proteolysis are each capable of modifying the nucleocytoplasmic distribution of proteins. In the case of transcription factors, control of these structural modifications affects access of the transcription factor to the chromatin. This management of cellular distribution, in turn, regulates gene expression.