GFRαThe GDNF family receptor-α proteins are a group of co-receptors which form complexes with GDNF-family ligands to activate RET, the receptor of the GFLs. The GFRα co-receptors include the following: GFRα1 – preference for GDNF GFRα2 – preference for neurturin GFRα3 – preference for artemin GFRα4 – preference for persephin GFRAL - receptor for GDF15