Rac and nuclear translocation of signal transducers and activators of transcription factors.
Signal transducers and activators of transcription (STATs) are tyrosine phosphorylated upon cytokine stimulations, and tyrosine-phosphorylated STATs (p-STATs) enter the nucleus to activate a variety of target genes. However, how activated STATs are transported to the nucleus has remained unclear. We have demonstrated that the small Rho GTPase Rac1 and the GTPase activating protein MgcRacGAP promote nuclear translocation of p-STATs via the importin alpha/beta pathway through mediating a complex formation of p-STATs with importin alpha. This chapter discusses the use of an in vitro nuclear transport assay with Flag-tagged purified proteins, providing detailed protocols regarding such experiments. Although this chapter focuses on STATs, Rac, and MgcRacGAP the methods described here can be adapted easily to other nuclear factors and their regulators.
Kawashima
Toshiyuki
T
Division of Cellular Therapy, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
Kitamura
Toshio
T
D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism*; D004072:Digitonin / Q000494:pharmacology; D020690:GTPase-Activating Proteins / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D018832:Molecular Chaperones / Q000502:physiology; D050791:STAT Transcription Factors / Q000502:physiology*; D050799:STAT5 Transcription Factor / Q000502:physiology; D018411:Spodoptera; D020830:rac1 GTP-Binding Protein / Q000502:physiology*
D020690:GTPase-Activating Proteins; D018832:Molecular Chaperones; D050791:STAT Transcription Factors; D050799:STAT5 Transcription Factor; C115995:mgcRacGAP; D020830:rac1 GTP-Binding Protein; D004072:Digitonin