CD95, BIM and T cell homeostasis.

The relative importance of the intrinsic and extrinsic apoptotic pathways in the control of haematopoietic cell homeostasis has been a matter of debate for many years. Cell death is omnipresent in this cellular compartment and ensures the removal of cells that are not properly equipped to assume their function as well as those that have assumed function but are no longer required. In this Review we focus on the roles of CD95 (also known as FAS) and BCL-2-interacting mediator of cell death (BIM), two major regulators of apoptosis in T cell homeostasis, with a particular emphasis on their cooperation in the shutdown of T cell responses.