Clone REA272 recognizes the N-terminus of the signal transducer and activator of transcription 1-α/β (STAT1) antigen, regardless of phosphorylation status. STAT1 is expressed in two alternatively spliced isoforms (91 kDa STAT1α and 84 kDa STAT1β) and clone REA272 recognizes both isoforms. STAT1 expression is found ubiquitously. It is involved in upregulating genes due to a signal by either type I, type II, or type III interferons. In response to interferon γ (IFN-γ) stimulation, the STAT1 subunits become tyrosine-phosphorylated at Y701, and the complex is translocated to the nucleus. STAT1 forms homodimers or heterodimers with STAT3 that bind to the IFN-γ activated sequence promoter element. In response to either IFN-α or IFN-β stimulation, STAT1 forms a heterodimer with STAT2 that can bind the interferon stimulated response promoter element. In either case, binding of the promoter element leads to an increased expression of interferon stimulated genes.

Additional information: Clone REA272 displays negligible binding to Fc receptors.