The state of the STATs: recent developments in the study of signal transduction to the nucleus

The STATs (signal transducers and activators of transcription) are latent cytoplasmic proteins that, upon activation by cell surface bound polypeptide ligands, move to the nucleus to direct transcription. A variety of protein-protein interactions that affect the function of STATs has been recently recognized. It has become clear that the STATs are functional mosaics, or mixtures of signal transduction and transcription modules.