GRAFS

The GPCR superfamily is the largest gene family in the human genome containing approximately 800 genes.^[1] As the vertebrate superfamily can be phylogenetically grouped into five main families the GRAFS classification system has been proposed.

GRAFS stands for Glutamate, Rhodopsin, Adhesion, Frizzled/Taste2, Secretin.^[2] They correspond to classical classes C (class C, glutamate), A (rhodopsin-like), B2 (Secretin receptor family, long N-terminal), F (Frizzled/Smoothened), and B1+3 (other secretin).^[3] Taste2 has more recently considered to be closer to Rhodopsin-like receptors.^[4]

See also

• G protein-coupled receptor#Classification