The Ins and Outs of STAT1 Nuclear Transport
This STKE Review, with 4 figures and 107 references, discusses the mechanisms underlying the regulation of the subcellular distribution of the signal transducers and activators of transcription (STATs), focusing on STAT1, the founding member of this family of transcription factors. The STATs represent a family of transcription factors, activated by tyrosine phosphorylation in response to cytokine or growth factor signaling, that provide a link between activation of cell surface receptors and the expression of target genes. After tyrosine phosphorylation, inactive cytoplasmic STAT1 dimerizes. Dimerization leads to a conformational change that exposes a nuclear import signal that allows STAT1 to be transported to the nucleus. In the nucleus, the STAT1 dimer binds to the DNA of target genes and activates transcription. Dephosphorylation of the STAT1 dimer leads to dissociation from DNA and exposes a nuclear export signal, leading to STAT1 relocation back to the cytoplasm.