Interleukin 23 receptor (IL-23R) is a type I cytokine receptor, and IL-23R pairs with the receptor molecule IL12RB1/IL12Rbeta1, and both are required for IL23A signaling. Also, IL-23R associates constitutively with Janus kinase 2 (JAK2), and binds to transcription activator STAT3 in a ligand-dependent manner. Furthermore, IL-23R mediates T-cells, NK cells and possibly certain macrophage/myeloid cells stimulation probably through activation of the Jak-Stat signaling cascade. As for IL-23, it may be responsible for autoimmune inflammatory diseases and be important for tumorigenesis.