The solution structure of the cytokine-binding domain of the common β-chain of the receptors for granulocyte-macrophage colony-stimulating factor, interleukin-3 and interleukin-5

Abstract

The haemopoietic cytokines, granulocyte-macrophage colony-stimulating factor, interleukin-3 and interleukin-5 bind to cell-surface receptors comprising ligand-specific α-chains and a shared β-chain. The β-chain is the critical signalling subunit of the receptor and its fourth domain not only plays a critical role in interactions with ligands, hence in receptor activation, but also contains residues whose mutation can lead to ligand-independent activation of the receptor. We have determined the NMR solution structure of the isolated human fourth domain of the β-chain. The protein has a fibronectin type III fold with a well-defined hydrophobic core and is stabilised by an extensive network of ..