Ras regulation and function in lymphocytes

The GTPase, Ras, is rapidly activated in antigen receptor stimulated T cell s, B cells and mast cells. Ras can bind to diverse effector molecules when activated and thereby switch on multiple downstream effector pathways. In l ymphocytes Ras plays an important role in the signalling pathways that acti vate transcription factors involved in cytokine gene induction. Ras is also a key component of the complex regulatory networks that control T and B ce ll development.