By contrast, overexpression of GRK2 in rat basophilic leukemia (RBL-2H3) cells results in enhanced IgE-mediated degranulation and cytokine generation without affecting the expression levels of any of the FcεRI subunits (α,β,γ) or IgE-mediated phosphorylation of Fcγ (5). This evidence concerns the gene IGHE and leukemia.