AP BIOLOGY

Detailed explanation-1: -Death receptors are members of the tumor necrosis factor receptor superfamily characterized by a cytoplasmic region known as the “death domain” that enables the receptors to initiate cytotoxic signals when engaged by cognate ligands.

Detailed explanation-2: -Apoptosis or programmed cell death can be induced by a variety of stimuli including activation of death receptors. This subgroup of the TNF/NGF-receptor-superfamily activates caspases, a family of aspartyl-specific cysteine-proteases, which are the main executioners of apoptosis.

Detailed explanation-3: -TNFR1 is a death receptor (DR) and harbors a death domain (DD) in its cytoplasmic part (Tartaglia et al., 1993). The DD is a conserved type of protein-protein interaction domain which enables DRs to interact homotypically with cytoplasmic proteins also harboring a DD (Park et al., 2007).

Detailed explanation-4: -Many diverse activities of tumor necrosis factor (TNF) are signaled through TNF receptor 1 (TNFR1). We have identified a novel 34 kDa protein, designated TRADD, that specifically interacts with an intracellular domain of TNFR1 known to be essential for mediating programmed cell death.