Glial cell line-derived neurotrophic factor–GDNF family receptor alpha-1–Rearranged during transfection signaling complex (GDNF–GFRα1–RET)

The GDNF–GFRα1–RET signaling complex is a tripartite molecular assembly essential for the development and maintenance of various neuronal populations, most notably dopaminergic neurons in the substantia nigra (UniProt P39905, P56159, P07949). The signaling process begins with the binding of the ligand, Glial cell line-derived neurotrophic factor (GDNF), to its high-affinity co-receptor, GDNF family receptor alpha-1 (GFRα1). This binary complex then induces the dimerization and autophosphorylation of the Rearranged during transfection (RET) receptor tyrosine kinase, triggering downstream signaling pathways such as MAPK/ERK and PI3K/Akt (Airaksinen & Saarma, 2002). Beyond its neuroprotective roles, this complex is critical for kidney morphogenesis and the regulation of spermatogenesis. Dysregulation of this signaling axis is implicated in several pathologies; loss-of-function mutations in RET or GFRα1 are associated with Hirschsprung disease, while gain-of-function RET mutations drive various thyroid and lung cancers (PubMed 29063013). In therapeutic contexts, GDNF and its mimetics are being investigated for their potential to halt or reverse the progression of Parkinson's disease by promoting the survival of degenerating neurons (ClinicalTrials.gov NCT00004571). Conversely, RET-specific inhibitors like selpercatinib are utilized in oncology to block the aberrant signaling of this complex in RET-driven malignancies. Therapeutic challenges include the difficulty of delivering large proteins across the blood-brain barrier and managing the systemic side effects of kinase inhibition.

Other names

GDNF/GFRalpha1/RET complexGDNF receptor complexGlial cell line-derived neurotrophic factor receptorRET–GFRα1–GDNF ternary complex

Agonism of the complex via GDNF or mimetics promotes the survival of dopaminergic neurons in neurodegenerative diseases, while pharmacological inhibition of the RET kinase component blocks oncogenic signaling in RET-dependent cancers (Airaksinen & Saarma, 2002; Mullard, 2021).