G-protein coupled receptor which is activated by type IV collagen, a major constituent of the basement membrane. Couples to G(i)-proteins as well as G(s)-proteins (PubMed:25118328). Essential for normal differentiation of promyelinating Schwann cells and for normal myelination of axons (PubMed:19745155). Also plays a role in inner ear development (PubMed:24067352). Plays an important role in heart development (PubMed:24082093). Necessary and sufficient for axon sorting by Schwann cells independently of the ADGRG6-CTF (PubMed:25695270). Expressed in Schwann cells of the posterior lateral line nerve and in brain. Detected from 30 hours post-fertilization to 4 days post-fertilization in Schwann cells of the posterior lateral line nerve. A short peptide sequence (termed the Stachel sequence) in the C-terminal part of the extra-cellular domain (ECD) functions as a tethered agonist. Upon structural changes within the ECD, e.g. due to extracellular ligand binding or mechanical movements, this intramolecular agonist is exposed to the 7TM domain, triggering G-protein activation. Morpholino knockdown of the protein results in defects in semicircular canal formation inner ear (PubMed:24067352). Belongs to the G-protein coupled receptor 2 family. Adhesion G-protein coupled receptor (ADGR) subfamily.