Cytokine pleiotropy and redundancy: A view from the receptor

Abstract

All cytokines, to a greater or lesser extent, exhibit pleiotropy (multiple biological actions) and redundancy (shared biological actions). The study of cytokine receptors, most of which belong to a structurally related hemopoietin domain family, has revealed that redundancy might be explained by the usage by related cytokines of a common receptor subunit usually termed the β-subunit and a unique ligand-specific α-subunit. Biological pleiotropy, on the other hand, requires that cytokine receptors exert differential activities on different cells. Potentially, this could be explained by the use of different β-subunits, unique signaling capacities of the α-subunit, differential signaling capacit..