Receptor for persephin. Mediates the GDNF-induced autophosphorylation and activation of the RET receptor (By similarity). Expressed in muscle, kidney, brain, stomach and intestine at E6. Levels increase in the brain from E6 to E18, and decrease in muscle and intestine. Levels in the kidney remain constant. From E10, expression also found in heart, lung, skin and liver. Levels in the liver increase dramatically at E18. At E18, highest expression found in kidney and brain. In the embryonic central nervous system, the spinal cord expressed the highest levels. Lower levels found in the medulla oblongata, pons, cerebellum and midbrain, and very low levels in the forebrain. Belongs to the GDNFR family.