More and more pleiotropy within the IL-6 family of cytokines

Historically, cytokines belonging to the gp130 family bind to specific ligand-binding receptors that stimulate cell signaling through a receptor complex comprising gp130 or gp130 together with another structurally related signaling receptor. However, recent findings increasingly dispel these stereotypes and suggest that the receptor specificity of gp130-activating cytokines is less strict than originally assumed. Weitz et al. now provide the latest example of this pleiotropy and report that human interleukin-6 can bind and stimulate signaling via the interleukin-11 receptor. Possible biological and therapeutic consequences of these findings are discussed.