Mas-related G-protein coupled receptor member X2 is a protein that in humans is encoded by the MRGPRX2 gene.

Function: Orphan receptor. Probably involved in the function of nociceptive neurons. May regulate nociceptor function and/or development, including the sensation or modulation of pain. Cortistatin-14 seems to be a high potency ligand at this receptor. Cortistatin has several biological functions including roles in sleep regulation locomotor activity, and cortical function. In receptor-expressing cells, cortistatin-stimulated increases in intracellular Ca(2+) but had no effect on basal or forskolin-stimulated cAMP levels, suggesting that this receptor is G(q)-coupled.