Persephin is a neurotrophic factor that belongs to the glial cell line-derived neurotrophic factor (GDNF) family. Persephin shares a large degree of structural similarity to GDNF, artemin, and neurturin, and has overall neuroprotective activity. Persephin signals through GRFα4 (glycosylphosphatidylinositol (GPI)-linked GDNF receptor family member) which signals through the receptor tyrosine kinase RET. Unlike GDNF and neurturin, persephin only promotes the growth and survival of central dopaminergic and motor neurons, but not peripheral neurons (Milbrandt et al.). In vitro, persephin only promotes survival of neurons that co-express GPI-linked GRFα4 and RET (Enokido et al.; Lindahl et al.). Mice lacking persephin showed increased cell death after cerebral ischemia, however administration of persephin before ischemia dramatically reduced neuronal cell death (Tomac et al.).