Mas-related G-protein coupled receptor member X2 is a protein that in humans is encoded by the MRGPRX2gene.[5][6]
It is most abundant on cutaneous mast cells.
Agonists are gyrase inhibitors like ciprofloxacin and non-depolarizing neuromuscular blocking agents like atracurium as well as vancomycin. Activation of MRGPRX2 leads to mast cell degranulation with subsequent pseudo-allergic reactions.
Yang S, Liu Y, Lin AA, et al. (2005). "Adaptive evolution of MRGX2, a human sensory neuron specific gene involved in nociception". Gene. 352: 30–35. doi:10.1016/j.gene.2005.03.001. PMID15862286.