Janus kinase 2 - Signal transducer and activator of transcription 3 signaling axis (JAK2-STAT3)

The Janus kinase 2 (JAK2) - Signal transducer and activator of transcription 3 (STAT3) signaling axis is a fundamental pathway that converts extracellular chemical signals from cytokines and growth factors into a transcriptional response (UniProt P41235, P40763). Upon activation by ligands such as Interleukin-6 (IL-6), JAK2 undergoes autophosphorylation and subsequently phosphorylates STAT3, which then forms dimers and translocates to the nucleus to regulate genes involved in hematopoiesis, inflammation, and cell survival (PubMed: 28543595). In many pathological states, particularly myeloproliferative neoplasms (MPNs) and various solid tumors, this pathway is constitutively active due to mutations like JAK2 V617F or overactive cytokine signaling (PubMed: 15772674). Therapeutic intervention primarily focuses on JAK2 inhibitors, such as Ruxolitinib and Fedratinib, which are used to treat myelofibrosis and polycythemia vera by dampening this overactive signaling (StatPearls: NBK557551). Additionally, direct STAT3 inhibitors and antisense oligonucleotides are under clinical investigation to overcome resistance and directly target the oncogenic transcription factor (PubMed: 31036066). Understanding this axis is crucial for managing hematologic disorders and developing precision oncology therapies.

Other names

JAK2-STAT3 pathwayJAK2-STAT3 signalingJanus kinase 2/Signal transducer and activator of transcription 3 axisJAK2-STAT3 signaling cascade

Small-molecule inhibitors typically target the ATP-binding pocket of Janus kinase 2 (JAK2), preventing its ability to phosphorylate Signal transducer and activator of transcription 3 (STAT3). This inhibition blocks STAT3 dimerization, nuclear translocation, and subsequent DNA binding, thereby halting the transcription of genes essential for cell cycle progression and anti-apoptosis.