Ligand for the GFR-alpha-3-RET receptor complex but can also activate the GFR-alpha-1-RET receptor complex. Supports the survival of sensory and sympathetic peripheral neurons in culture and also supports the survival of dopaminergic neurons of the ventral mid-brain. Strong attractant of gut hematopoietic cells thus promoting the formation Peyer's patch-like structures, a major component of the gut-associated lymphoid tissue (By similarity). Homodimer; disulfide-linked. Binds to RET (By similarity). Cochlea. Expressed at higher level in sesorineural epithelium than in the modiolus region or substantia nigra. Expressed during embryogenesis. At embryonic day 14 (E14) not detected in the brain or spinal cord. A striking expression seen in the nerve roots but not in the developing neurons of the dorsal root ganglia. A significant expression also seen around the superior mesentric artery. Belongs to the TGF-beta family. GDNF subfamily.