In addition, G protein-coupled receptor kinase 2 (GRK2) and the adapter protein β-arrestin2 have been shown to regulate MRGPRX2-mediated responses in vitro, also MrgprB2-mediated rosacea, IgE-mediated allergic lung inflammation and systemic anaphylaxis in vivo (70–75). Here, GRK2 is linked to anaphylaxis.