NGFR p75 or CD271 is a 75kD transmembrane glycoprotein consisting of an extracellular domain which contains four cysteine rich domains responsible for ligand binding, a transmembrane domain, and a cytoplasmic domain. NGFR p75 displays paradoxical functions when acting alone or with other receptor proteins. Working in concert with Trk receptors, it recognizes neurotrophins and transmits trophic signals into the cell. NGFR p75 is necessary for regulating neuronal growth, migration, differentiation and cell death during development of the central and peripheral nervous system.