Janus kinase enzyme (JAK)

Janus kinase enzymes (JAKs) are a family of intracellular, non-receptor tyrosine kinases (JAK1, JAK2, JAK3, and TYK2) that are critically involved in cytokine signaling through the JAK-STAT pathway. These enzymes dock to the cytoplasmic side of type I and II cytokine receptors and, upon cytokine stimulation, phosphorylate themselves and their associated receptor chains to create docking sites for STAT proteins, which then translocate to the nucleus and regulate gene expression. JAK-STAT signaling is integral to processes such as immune cell development and function, hematopoiesis, inflammation, proliferation, and survival, as well as pathologies including autoimmune disease, cancer, and immunodeficiency syndromes. JAK inhibitors represent an important therapeutic class for treating autoimmune conditions and certain cancers, but their use can be complicated by immunosuppression and related adverse effects.

Other names

JAKjust another kinaseJanus kinasesJAKs

Inhibition of JAK catalytic activity (JAK inhibitors block phosphorylation/activity of JAK, preventing transmission of cytokine signals via the JAK-STAT pathway)