The GTPase Ran: regulation of cell life and potential roles in cell transformation.

The GTPase Ran plays a crucial role in nucleo- cytoplasmic transport of tumor suppressors, protooncogenes, signaling molecules and transcription factors. It also plays direct roles in mitosis, through which it regulates faithful chromosome segregation and hence the generation of genetically stable cells. Ran operates through a group of effector proteins. In this review we summarize growing evidence suggesting that deregulated activity of Ran or its effectors can contribute to pathways of cell transformation and facilitate tumor progression.