STAT 1, phosphorylated (Tyr701) (Signal Transducer and Activator of Transcription 1)

In unstimulated cells, STAT proteins exist largely in the cytoplasm as latent transcription factors. In response to treatment of target cells with cytokines or in some cases growth factors, STATs undergo tyrosine phosphorylation, homo-or heterodimerization, nuclear translocation, and DNA binding which results in transcriptional activation of distinct target genes. Phosphorylation of a conserved tyrosine residue located near the carboxy-terminus of all STAT proteins is required for both dimerization and DNA binding. Tyrosine phosphorylation is therefore a useful marker for STAT activation. At least one and oftentimes several STAT proteins are activated in response to cytokines that utilize receptors from the cytokine receptor superfamily. Nevertheless, a striking specificity of specific STAT activation is seen in response to individual cytokines. Stimulation of responsive cells with IFNa/b induces the formation of a transcription complex termed ISGF3. This complex binds to the interferon-stimulated response element (ISRE), activating the transcription of responsive genes. The ISGF3 complex consists of tyrosine phosphorylated STAT1a, STAT1b (p84), STAT2 and p48, a 48kD DNA binding protein that is specific for the IFN-stimulated response element. Formation of this complex and its migration into the nucleus is dependent upon tyrosine phosphorylation of STAT1a/b and STAT2. Stimulation of cells with IFN-g results in tyrosine phosphorylation of STAT1a (p91), but not of STAT2. Phosphorylation of STAT1a results in its homodimerization and migration into the nucleus where it binds to the IFN-g activated site (GAS). The STAT1a and STAT1b isoforms arise by alternative splicing of a single gene. The only difference between the two proteins is that STAT1b lacks 38 carboxy-terminal amino acids. Contained within these 38 terminal amino acids of STAT1a is a critical serine residue (Ser- 727) whose phosphorylation is required for maximal IFN-g induced transcription. \n\nApplications: \nSuitable for use in ELISA, Western Blot and Immunohistochemistry. Other applications not tested.\n\nRecommended Dilution:\nWestern Blot: 1-2ug/ml \nELISA: 0.1-1ug/ml\nImmunohistochemistry (Formalin-fixed, paraffin-embedded sections): 5ug/ml; Heat induced epitope retrieval (HIER) with citrate buffer, pH 6.0, is required.\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, add sterile glycerol (40-50%), aliquot and store at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

Prices direct from United States Biological

Quick response times

Exclusive Biosave savings/discounts

SPECIFICATIONS

Catalog Number

S7969-09

Size

50ug

Applications

ELISA, IHC, WB

Hosts

Mouse

Reactivities

Hum, Mouse

Form

Supplied as a liquid in PBS, pH 7.4, 0.05% sodium azide.

P Type

Mab

Purity

Purified by immunoaffinity chromatography.

Isotype

IgG2a,k

References

1. Levy, D.E., et al., Genes Dev. 2: 383-393 (1988). 2. Schindler, C., et al., Science 257: 809-815 (1992). 3. Schindler, C., et al., Proc. Natl. Acad. Sci. USA 89: 7836-7839 (1992). 4. Qureski, S.A., et al., Proc. Natl. Acad. Sci. USA 92: 3829-3833 (1995). 5. Fu, X.-Y., et al., Proc. Natl. Acad. Sci. USA 87: 8555-8559 (1990). 6. Veals, S.A., et al., Mol. Cell Biol. 12: 3315-3324 (1992). 7. Shuai, K., et al., Science 259: 1808-1812 (1992). 8. Decker, T. et al., EMBO J. 10: 927-932 (1991). 9. Lew, D., et al., Mol. Cell. Biol. 11: 182-191 (1991). 10. Ihle, J.N., et al., Trends in Biochem. Sci. 19: 222-227 (1994).

Additional Info

Recognizes the tyrosine-701 phosphorylated form of STAT1 protein. Does not exhibit appreciable crossreactivity with corresponding tyrosine phosphorylated forms of other STAT proteins or with other endogenous phosphotyrosine containing proteins. Species Crossreactivity: Human and mouse.