Glial Cell Line-derived Neurotrophic Factor (GDNF) is the neurotrophic factor, belonging to the GDNF family of ligands (GFL) and identifying as a therapeutic candidate in Parkinson's disease.GDNF is a 23.7 kDa protein containing 211 residues that plays a critical role in promoting the survival and differentiation of midbrain dopamine neurons. Besides, GDNF is revealed to facilitate the development of peripheral tissues such as kidney, pancreas and lung. Additionally, as a member of GFL, GDNF also takes part in the progression of tumor.