Crystal structure of the GM-CSF receptor ternary complex. Cartoon ribbon picture showing the hexamer complex as it would sit on a cell surface. One monomer of βc is shown in green (chain a) and the other in dark blue (chain b). GM-CSF is shown in magenta, and GMRα in red. Labels denote the protein domains, whereas the location of the interacting surfaces (sites I-III) is indicated. The transmembrane regions, missing in the structure, are shown stylistically as dashed lines. The Jak2 molecules, which are attached to the cytoplasmic tails and require transphosphorylation for receptor activation, are shown as blue spheres. This and subsequent figures were prepared with PyMOL.¹⁴⁴