Involved in cell adhesion and probably in cell-cell interactions. Regulates the migration of neural precursor cells. Receptor for collagen III/COL3A1 in the developing brain and involved in regulation of cortical development, specifically in maintenance of the pial basemant 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. Isoforms show differences in receptor signaling, specifically in serum response element (SRE) transcriptional activation upon overexpression. Overexpression inhibits melanoma tumor growth and metastasis and, during melanoma progression, regulates VEGFA production and angiogenesis through PRKCA; unprocessed GPR56 is inhibiting and GPR56 NT is activating angiogenesis. Required for normal cortical development and regulation of neuroprogenitor cells proliferation. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804