GPR56 encodes a member of the G protein-coupled receptor family. The protein contains 7 transmembrane domains and a mucin-like domain in the N-terminal region. The gene is implicated in the regulation of brain cortical patterning. The protein binds specifically to transglutaminase 2 in the extracellular space. Expression of this gene is downregulated in melanoma cell lines, and overexpression of this gene can suppress tumor growth and metastasis.

The predicted 693-amino acid GPR56 protein shares 26 to 32% sequence identity with the 4 class B-like orphan receptors. Like these receptors, GPR56 contains 7 transmembrane domains as well as a mucin-like domain and cysteine box in the N-terminal region.