Nucleocytoplasmic shuttling of transcription factors

To elicit the transcriptional response following intra- or extracellular st imuli, the signals need to be transmitted to their site of action within th e nucleus. The nucleocytoplasmic shuttling of transcription factors is a me chanism mediating this process. The activation and inactivation of the tran scriptional response is essential for cells to progress through the cell cy cle in a normal manner. The involvement of cytoplasmic and nuclear accessor y molecules, and the general nuclear membrane transport components, are ess ential for this process. Although nuclear import and export for different t ranscription factor families are regulated by similar mechanisms, there are several differences that allow for the specific activation of each transcr iption factor. This review discusses the general import and export pathways found to be common amongst many different transcription factors, and highl ights a select group of transcription factors that demonstrate the diversit y displayed in their mode of activation and inactivation.