Signal transducer and activator of transcription 3 (acute-phase response factor) Adenovirus (Ad-STAT3)

Stats (signal transducers and activators of transcription) are tyrosine phosphorylated transcription factors activated by JAK family kinases. Various ligands, including interferons and growth factors, induce activation of the JAK kinases, which induce Stat activation. Stat1 and Stat2 are induced by IFN-alpha and form a heterodimer that is part of the ISGF-3 transcription factor complex. Stat3-beta is activated by EGF and IL-6. Stat3-alpha is activated by EGF. Highest expression of Stat4 is observed in the testis and myeloid cells. IL-12 has been identified as an activator of Stat4. Stat5 can be activated by prolactin and by IL-3. Stat6 is involved in IL-4 activated signaling pathways. Stat-1 and Stat-3 bind the serum-inducible element (SIE) and GAS/ISRE elements are also known to be STAT-binding sites.