Members of the TNFR (Tumor Necrosis Factor Receptor) superfamily are important for cell growth and survival. CD27 is a member of the TNFR superfamily, which includes TNFR types I and II, NGFR (Nerve Growth Factor Receptor), CD30 (associated with Hodgkin lymphoma), Fas/Apo1 (CD95), CD40, 4–1BB, and OX40. These receptors are known to play a very important role in cell growth and differentiation, as well as apoptosis or programmed cell death. In addition to providing costimulatory signals for cell proliferation, ligation of both TNFR1 and Fas can result in programmed cell death or apoptosis. The underlying mechanism requires an intact 80-aa stretch present in the cytoplasmic tails of both TNFR1 and Fas, termed the DD (Death Domain) (Ref.1). CD27 is a [...]