Cytokine JAK/STAT signalling
Cytokine JAK/STAT signalling — full pathway. Six receptor complexes shown end-to-end: a cytokine dimerises its receptor chains, the associated Janus kinases trans-phosphorylate, a STAT docks and is phosphorylated, then dimerises and enters the nucleus to bind GAS/ISRE elements. The cycle is tuned by three tiers of brakes — SHP-2 (receptor), SOCS/CIS (JAKs, a STAT-induced feedback loop) and PIAS / TC-PTP (nuclear STAT). Click any protein for the matching Assay Genie In Vivo antibody or ELISA kit.
The canonical cycle (left to right, top to bottom). A cytokine binds and brings two receptor chains together; the receptor-associated JAKs trans-phosphorylate one another and the receptor tails, creating phospho-tyrosine docking sites. A STAT is recruited through its SH2 domain, phosphorylated, released, and dimerises; the dimer translocates to the nucleus and binds a GAS element (or, for type I IFN, STAT1:STAT2 recruit IRF9 to form ISGF3, which binds ISRE).
Receptor → JAK → STAT specificity. IFN-γ (IFN-γR1/R2, JAK1/JAK2) → STAT1; type I IFN (IFNAR1/2, JAK1/TYK2) → ISGF3; IL-6 (IL-6R/gp130, JAK1/JAK2/TYK2) → STAT3; IL-12 (IL-12Rβ1/β2, JAK2/TYK2) → STAT4; IL-2 (IL-2Rβ/γc, JAK1/JAK3) → STAT5; IL-4 (IL-4Rα/γc, JAK1/JAK3) → STAT6. Each STAT sets a distinct gene programme — the same STATs that anchor the Assay Genie T-helper, Treg, myeloid and antiviral diagrams.
Three tiers of negative regulation. At the receptor, SHP-2 dephosphorylates the complex; at the JAKs, STAT-induced SOCS1/SOCS3/CIS form a classic feedback loop; in the nucleus, PIAS proteins block STAT-DNA binding and TC-PTP (PTPN2) dephosphorylates nuclear STATs. Assay Genie In Vivo functional-grade antibodies neutralise the input cytokines (anti-IFN-γ, anti-IFN-β, anti-IL-2, anti-IL-4), while receptors, JAKs, STATs and every regulator are covered by ELISA kits and antibodies. For research use only; not for diagnostic or therapeutic procedures. Mouse targets shown where available.
Every protein node links to a product: In Vivo antibodies for the input cytokines; the receptor chains, JAK kinases, STAT factors and SOCS/SHP/PIAS/TC-PTP regulators open the matching ELISA kit or antibody.