
The IL-17 family of cytokines contains six members: IL-17 (also known as IL-17A), IL-17B, IL-17C, IL-17D, IL-17E (also known as IL-25) and IL-17F. IL-17F, the most recently discovered cytokine in this family, shares strongest homology to IL-17A, a cytokine whose importance has been well documented in autoimmune and inflammatory diseases. IL-17F forms homodimers, binds to and signals via a heterodimeric transmembrane receptor complex consisting of IL-17RC and IL-17RA subunits. This heterodimeric receptor is shared by IL-17A. While IL-17A and IL-17F bind IL-17RC with comparable affinities, IL-17F binds IL-17RA with a far lower affinity than IL-17A (PMID: 19575028)...