Peptide analogues of consensus receptor sequence inhibit the action of cytokines on human basophils

A novel cytokine receptor family has been defined based on structural homologies between the extracellular receptor domains. All receptors share a WSXWS consensus sequence just outside the plasma membrane. To evaluate whether this box of homology has a role in receptor function we synthesized peptides encompassed within the WSXWS region. In a basophil mediator release assay, three peptides inhibited the priming effect of interleukin (IL)-3, IL-5, and granulocyte/macrophage colony-stimulating factor (GM-CSF) on synthesis of leukotriene C4 induced by chemotactic peptides. The study suggests that, analogous to the RGD motif in adhesive proteins, the WSXWS motif serves as a recognition site for functional protein-protein interaction of cytokine receptors.