Persephin is a neurotrophic factor, belonging to the GDNF family. Neurotrophic factors are important for the proper development and maintenance of the nervous system. These factors promote neuronal survival and can prevent the neuronal degeneration associated with injury, toxin exposure, or neurodegenerative disease. Persephin has a similar structure to other family members, glial cell line-derived neurotrophic factor, Artemin and neurturin. All these proteins belong to the cysteine-knot family of growth factors that assume stable dimeric structures. Persephin signals through a multicomponent receptor system, composed of RET and one of four GFR alpha (alpha1-alpha4) receptors. The GFRalpha4 was first identified in chicken and was later shown to be the preferential binding subunit for Persephin. In contrast to GDNF and Neurturin, Persephin does not support survival of peripheral neurons.