Receptor for persephin. Mediates the GDNF-induced autophosphorylation and activation of the RET receptor. May be important in C-cell development and, in the postnatal development of the adrenal medulla. Interacts with SORL1. Additional isoforms seem to exist. Tissue-specific and, developmentally regulated splicing. Expressed in many tissues including adrenal medulla, brain neurons, with highest levels in the cerebral cortex and hippocampus. Moderate levels found in the gut circular muscle and myenteric ganglia as well as in other peripheral ganglia, including the sensory dorsal root and trigeminal as well as superior cervical and sympathetic chain ganglia. Isoform a1, isoform a2, isoform b1 and isoform b2 are exclusively found in the thyroid, parthyroid and pituitary glands. Expressed in several tissues at different embryonic and postnatal stages such as the condensing mesenchyme of developing bones and developing nervous system. Expressed in the developing pituitary gland from 16 dpc and in developing thyroid C-cells from 14 dpc. In the ventral spinal cord, levels decline before birth. In the parathyroid, levels first detected in 3- to 6-week-old mice with high expression. In the adrenal medulla, expressed only in newborn, postnatal (P08) and adult mice. Isoform a1 and isoform b1 are prefentially expressed in 3-week-old thyroid, isoform a2 and isoform b2 in newborn and 6-week-old thyroid glands as well as in postnatal adrenal and pituitary glands. Alternative N-terminal. Probably non-functional. Alternative N-terminal. Probably non-functional. Alternative N-terminal. Probably non-functional. Belongs to the GDNFR family.