G-protein coupled receptor 161 (GPR161)

Key negative regulator of Shh signaling, which promotes the processing of GLI3 to GLI3R during neural tube development. Recruited by TULP3 and the IFT-A complicated to primary cilia and functions as a regulator of the PKA-dependent basal repression machines in Shh signaling by increasing cAMP levels, contributing to promote the PKA-dependent processing of GLI3 to GLI3R and repress the Shh signaling.

In presence of SHH, it's eliminated from primary cilia and is internalized into recycling endosomes, preventing its activity and allowing activation of the Shh signaling. Its ligand is unknown (By similarity).