Fig. 3.

Schematic representation of IL-10 family members signaling pathway, based on the IL-22 set of receptors. 1 Inactivated long- and short-chain class II cytokine receptors are bound to Janus-family tyrosine kinases (JAK1 and Tyk2). Inactivated STAT homodimers are found in the cytoplasm. 2 Interleukin binding on the extracellular portion of R1 and R2 activates intracellular JAK/Tyk phosphorylation. Tyrosine residues on either Jak/Tyk and on the receptors are phosphorylated. However, a soluble decoy receptor (IL-22BP) can interact with the IL-22 lacking transmembrane receptor activation. 3 STATs are recruited and phosphorylated, forming activated STAT dimers. 4 STAT dimers migrate to the nucleus activating cytokine specific induced genes