Receptor involved in cell adhesion and probably in cell-cell interactions. Mediates cell matrix adhesion in developing neurons and hematopoietic stem cells. Receptor for collagen III/COL3A1 in the developing brain and involved in regulation of cortical development, specifically in maintenance of the pial basement membrane integrity and in cortical lamination. Binding to the COL3A1 ligand inhibits neuronal migration and activates the RhoA pathway by coupling to GNA13 and possibly GNA12. Plays a role in the maintenance of hematopoietic stem cells and/or leukemia stem cells in bone marrow niche. Plays an essential role in testis development. Plays a critical role in tumourigenesis. ADGRG1 NT is proposed to inhibit receptor signaling; its interactions with extracellular ligands and /or homophilic ADGRG1 NT interactions may relieve the inhibition. Following ligand binding to the N-terminal fragment, the N-terminal fragment is released from the seven-transmembrane C-terminal fragment to unveil a new N-terminal stalk, which then stimulates G-protein-dependent signaling activity. The N-terminal stalk has also been shown to be dispensable for at least some G-protein-dependent signaling. Heterodimer of 2 chains generated by proteolytic processing; the large extracellular N-terminal fragment (ADGRG1 NT) and the membrane-bound C-terminal fragment (ADGRG1 CT) predominantly remain associated and non-covalently linked. ADGRG1 NT self-associates in a trans-trans manner; the homophilic interaction enhances receptor signaling. ADGRG1 CT interacts with ARRB2; the interaction is impaired by ADGRG1 ADGRG1 NTNT. Interacts with TGM2; TGM2 probably is not a ADGRG1 ligand and the interaction is reported controversial. Part of a GPCR-tetraspanin complex at least consisting of ADGRG1, CD81, eventually CD9, and GNA11 in which CD81 is enhancing the association of ADGRG1 with GNA11. Interacts with heparin; leading to the reduction of ADGRG1 shedding. Interacts with COL3A1 (By similarity). Interaction with its ligand COL3A1 leads to the release of ADGRG1 NT from the membrane and triggers the association of ADGRG1 CT with lipid rafts. Autoproteolytically cleaved into 2 fragments; the large extracellular N-terminal fragment and the membrane-bound C-terminal fragment predominantly remain associated and non-covalently linked. Shedding to yield the secreted ADGRG1 N-terminal fragment seems to involve metalloprotease(s). N-glycosylated. Contains sialic acid residues. Ubiquitinated. Undergoes polyubiquitination upon activation. Belongs to the G-protein coupled receptor 2 family. LN-TM7 subfamily.