Interleukin-13 receptor subunit alpha-1 (IL13RA1), with associated Non-receptor tyrosine-protein kinase 2 (TYK2), binds the IL4:IL4R:JAK2 complex to form the ligand-bound Type II IL4 receptor complex (IL4R2). IL4R2 is predominantly expressed on the surface of non-hematopoietic cells. It is also a receptor for Interleukin-13 (IL13) (Obiri et al. 1995, Aman et al. 1996, Hilton et al. 1996). Crystal structures of the IL4:IL4R:IL13RA1 and IL13:IL4R:IL13RA1 complexes have been determined (LaPorte et al. 2008).