GP130 is a signal-transducing subunit shared by the receptors for the IL-6 family of cytokines. There are many proteins which associate with gp130, such as CT-1, LIF, CNTF, OSM, and IL-11. GP130 has no intrinsic tyrosine kinase activity. Instead, it is phosphorylated on tyrosine residues after complexing with other proteins. The phosphorylation leads to association with JAK/Tyk tyrosine kinases and STAT protein transcription factors. In particular, STAT-3 is activated which leads to the activation of many downstream genes. Other pathways activated include RAS and MAPK signaling.
