STAT (Signal Transducers and Activators of Transcription) are a family of conserved transcription factors that transduce high-fidelity signals for the cytokine family of ligands and receptors as the principle substrates of JAK kinases. In resting cells, the STATs exist in an inactive state in the cytoplasm until activated. Activators include cytokines, growth factors, and some peptides. These activate JAK kinases, which when activated, bind to the STAT SH2 (Src homology domain-2) domain resulting in phosphorylation of STAT. Upon activation, STAT1, -3, -4, -5A, and -5B all form homodimers. STAT1 and STAT2, as well as STAT1 and STAT3 form heterodimers, and several STATs form tetramers, depending on the variables of the activating ligand (1). After dimerization, the STATs accumulate in the nucleus by way of nuclear transport. STAT5A and STAT5B appear to be most important to the function of growth hormone and prolactin and play critical roles in milk production. The phosphorylation of Tyrosine 694/699 is a hallmark of activated STAT5.

Suitable for use in Western Blot. Other applications not tested.

Western Blot: 1:1000 detected phospho-STAT5A/B in A431 cells stimulated with EGF. The lysates were resolved by electrophoresis, transferred to nitrocellulose and probed with S7972-13. Proteins were visualized using a goat anti-mouse secondary antibody conjugated to HRP and a chemiluminescence detection system. Optimal dilutions to be dtermoned by the researcher.

IFN-alpha induced HeLa cells, GM-CSF treated TF-1 cells.

Store product at 4°C in the dark. DO NOT FREEZE! Stable at 4°C for 12 months after receipt as an undiluted liquid. Dilute required amount only prior to immediate use. Further dilutions can be made in assay buffer. Caution: MaxLight™650 conjugates are sensitive to light. For maximum recovery of product, centrifuge the original vial prior to removing the cap.

Note: Applications are based on unconjugated antibody.