The STAT3 signalling pathway is a pathway activated by many different cytokines. It has also been found to be activated by many carcinogens. Cytokines are small proteins. These proteins are released by some of the cells in the immune system, and are vital to signalling pathways in the body of mammals. STAT3 is very important in the activation of the expression of certain mediators in the liver. STAT3 binds at the phosphotyrosine receptor which in turn phosphorylates tyrosine 705 at the C-terminal domain of STAT3, activating STAT3. If a receptor is missing tyrosine-kinase activity it will find tyrosine-kinases that are associated to the receptor, including JAK and Src when it is time for ligand engagement. Thanks to this recruitment, STAT3 is phosphorylated through the tyrosine phosphorylation cascade. This means that STAT3 is now activated, and its compounds disconnect from the receptor site, and relocate to the nucleus. Once there, the compounds bind to DNA response elements, and take part in many processes against target genes, such as apoptosis and cell proliferation, regulating their transcription.

Stat3 Signaling Pathway References