Signal transducers and activators of transcription 1 (STAT1) binding peptide. STAT1 is a biotinylated protein that contains an SH2 domain, which binds to specific phospho (pY)-containing peptide motifs. Interferon γ (IFNγ/type II IFN) activates STAT1 by its phosphorylation. STAT1 is a critical mediator of cytokine signalling and has been reported as a tumour suppressor in breast cancer, myeloma and leukaemia.
IFNγ is secreted by immune cells and signals through the IFNγ receptor and downstream signalling pathways including the janus kinase (JAK)/STAT pathway. IFNγ is a central mediator of the adaptive immune system and regulates macrophage activation to promote the expression of high levels of pro-inflammatory cytokines (Il-1β, IL-12, IL-23, and TNF-α); production of reactive nitrogen and oxygen intermediates; promotion of CD4+ T helper 1 (Th1) cell response and strong inflammatory activity. IFNγ inhibits viral replication and is essential for vaccine-mediated immune responses. IFNγ signalling is usually short-lived to elicit recovery of homeostasis, including tissue repair, however IFN-γ is elevated in severe adult asthma and is present in the airways of children with severe asthma. This indicates a key role for IFNγ in inflammatory conditions.
Peptide contains a phosphorylated tyrosine residue and an N-terminal 5-carboxyfluorescein (5-FAM), a widely used green fluorescent tag