Figure 4.

The cytokine homology region (CHR) forms the basis of all cytokine receptors. (A) The CHR from a Class I receptor (Growth Hormone Receptor) is shown with the two FnIII domains, disulfide bonds and WSXWS motif highlighted. All receptors contain a CHR however many receptors, especially those that recognize Class I cytokines, have additional FnIII and Ig domains and this results in a large variety of receptor architectures and stoichiometries. (B) Structures and models of a diverse range of cytokine:receptor complexes.