Janus kinase-signal transducer and activator of transcription pathway (JAK/STAT pathway)

The JAK/STAT pathway is a highly conserved intracellular signaling cascade that transmits information from extracellular chemical signals—primarily cytokines and growth factors—through cell surface receptors to the nucleus, resulting in gene transcription. It plays a central role in regulating immunity, cell division, differentiation, apoptosis (cell death), survival, inflammation, and tumorigenesis. The canonical sequence is: ligand → receptor → Jak activation → Stat phosphorylation/dimerization → nuclear translocation → gene expression modulation. Pathway dysregulation underlies many immune disorders/cancers. Multiple drugs now target this axis therapeutically.

Inhibition of JAK kinases, leading to reduced STAT phosphorylation and downstream signaling.