Phospho-STAT4 (Tyr693) Monoclonal Antibody (4LURPIE), PE, eBioscience™, Invitrogen™

Description

• Description: This 4LURPIE monoclonal antibody recognizes human and mouse signal transducer and activator of transcription 4 (STAT4) when phosphorylated on tyrosine 693 (Y693)
• STAT proteins are activated by ligand binding to cytokine receptors that associate with Janus kinase (JAK) family members
• Following their phosphorylation by JAK proteins, STAT proteins translocate to the nucleus where they bind to DNA and regulate transcription of specific genes in a cell type- and cytokine-specific manner
• STAT4 is activated by IL-12 or type 1 IFN (IFN alpha, IFN beta)
• STAT4 is required for optimal Th1 differentiation in vivo
• Interestingly, although IFN alpha can lead to phosphorylation of STAT4 in mouse T cells, the phosphorylation is much weaker than that induced by IL-12 and is transient
• Thus, IFN alpha phosphorylation of STAT4 does not contribute to STAT4-mediated Th1 development or IFN gamma production by Th1 cells in mice
• In contrast, IFN alpha does promote Th1 development and function of human CD4+ T cells
• Specificity of this 4LURPIE clone was determined by ELISA and flow cytometry
• Applications Reported: This 4LURPIE antibody has been reported for use in intracellular staining followed by flow cytometric analysis
• Applications Tested: This 4LURPIE antibody has been pre-titrated and tested by intracellular staining followed by flow cytometric analysis of stimulated normal human peripheral blood cells
• This can be used at 5 μL (0.25 μg) per test
• STAT4 was originally identified using degenerate primers complementary to sequences encoding conserved regions of other STAT proteins
• The STAT4 protein is most similar to STAT1 (52%) and STAT3 (47%)
• Functionally, STAT4 is similar to other STAT family members in that it can be tyrosine phosphorylated by Jak1 or Jak2
• STAT4 forms homodimers and heterodimers with related STAT family members
• Tyrosine phosphorylated STAT4 can bind the IFN-gamma activated site (GAS)
• Serine phosphorylation of STAT is also required for maximal transcriptional activity
• STAT4 expression is restricted to the thymus, spleen and testis
• Until recently the cytokine(s) responsible for activation of STAT4 had not been identified
• STAT4 is now known to be activated by the cytokine interleukin 12 (IL-12)
• IL-12 is required for the T-cell independent induction of IFN-gamma which is a key step in the initial suppression of bacterial and parasitic infections
• In addition, IL-12 is required for the development of a Th1 response which is necessary for effective host defense against intracellular pathogens
• STAT4-deficient mice display impaired IL-12 development of Th1 cells and enhanced development of Th2 cells
• A recent study in mouse has shown that in response to viral infection IFN-a/b activation of STAT4 is required for IFN-g production.