CD271, (or p75NTR) is the sixteenth member of the Tumor Necrosis Factor receptor (TNFR) super family of transmembrane proteins. Members of the TNFR family including CD271, share homology in their extracellular domain, and have a cytoplasmic death domain, although CD271 has unique intracellular structure and downstream signalling partners. CD271 is also differentiated from other members of the TNFR receptor family in that it binds pro and mature neurotrophins and affects the growth, differentiation and death of the nervous system. The ligands for CD271 are neurotrophins, which are Nerve Growth Factor (NGF), Brain-Derived Growth factor (BDNF), Neurotrophin 3 (NT3) and Neurotrophin 4/5 (NT4/5). Recent studies have provided evidence that CD271 also serves as a receptor for the pro-forms of these neurotrophins.