BD Phosflow™ Alexa Fluor® 488 Mouse Anti-Stat1 (pY701)

Stat (Signal transducer and activators of transcription) proteins mediate the biological activity of cytokines, including interleukins, interferons, erythropoietin, and growth factors.  Ligand-receptor interaction activates constitutively-associated JAK family kinases as well as subsequent recruitment and activation of Stat proteins by tyrosine phosphorylation.  Active Stat proteins then move to the nucleus to promote transcription of cytokine-inducible genes.  Seven Stat proteins have been cloned, each of which is differentially expressed and/or activated in a cytokine-specific and cell type-specific manner.  Stat1 and Stat2 are components of the ISGF3 (Interferon-Stimulated Gene Factor 3) complex, the primary transcription activator induced by interferon binding to a specific cell-surface receptor.  Stat1 has two alternatively spliced isoforms, 91-kDa Stat1α and 84-kDa Stat1β; Stat1α has 38 additional C-terminal amino acids.  In response to the binding of IFNα, IFNγ, EGF, PDGF, or CSF-1 to their respective receptors, the Stat1 subunits become tyrosine-phosphorylated at Y701, and the complex translocates to the nucleus. This forms an active complex that includes the DNA-binding p48 subunit, and is responsible for modulating interferon-stimulated genes (ISGs) transciption.

The 4a monoclonal antibody recognizes the phosphorylated Y701 in Stat1α and Stat1β.