Cell Signaling Technology

Product Pathways - Jak/Stat Pathway

Stat1 Antibody #9172

Applications Reactivity Sensitivity MW (kDa) Source
W IP ChIP H M R Mk (B) (Dg) Endogenous 84, 91 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  ChIP=Chromatin IP
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  B=Bovine  Dg=Dog
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Stat1 Antibody detects endogenous levels of total Stat1 protein. The antibody detects both Stat1alpha (91kDa) and Stat1beta (84 kDa) isoforms.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to the sequence of human Stat1. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa cells 48 hours following mock transfection, transfection with non-targeted (control) siRNA or transfection with Stat1 siRNA. Stat1 was detected using Stat1 Antibody #9172, and p42 was detected using p42 MAPK Antibody #9108. The Stat1 Antibody confirms silencing of Stat1 expression, and the p42 MAPK Antibody is used to control for protein loading and siRNA specificity.

Western Blotting

Western Blotting

Western blot analysis of extracts from SK-MEL-28 cells, untreated or IFN-alpha-treated (100 ng/ml), using Phospho-Stat1 (Tyr701) Antibody #9171 (upper) or Stat1 Antibody (lower).

Chromatin IP

Chromatin IP

Chromatin immunoprecipitations were performed with cross-linked chromatin from 4 x 106 HT-1080 cells treated with IFN-γ (50 ng/ml) for 30 minutes and either 10 μl of Stat1 Antibody or 2 μl of Normal Rabbit IgG #2729 using SimpleChIP® Enzymatic Chromatin IP Kit (Magnetic Beads) #9003. The enriched DNA was quantified by real-time PCR using human IRF-1 promoter primers, SimpleChIP® Human TAP1 Promoter Primers #5148, and SimpleChIP® Human α Satellite Repeat Primers #4486. The amount of immunoprecipitated DNA in each sample is represented as signal relative to the total amount of input chromatin, which is equivalent to one.


Background

The Stat1 transcription factor is activated in response to a large number of ligands (1) and is essential for responsiveness to IFN-α and IFN-γ (2,3). Phosphorylation of Stat1 at Tyr701 induces Stat1 dimerization, nuclear translocation, and DNA binding (4). Stat1 protein exists as a pair of isoforms, Stat1α (91 kDa) and the splice variant Stat1β (84 kDa). In most cells, both isoforms are activated by IFN-α, but only Stat1α is activated by IFN-γ. The inappropriate activation of Stat1 occurs in many tumors (5). In addition to tyrosine phosphorylation, Stat1 is also phosphorylated at Ser727 through a p38 mitogen-activated protein kinase (MAPK)-dependent pathway in response to IFN-α and other cellular stresses (6). Serine phosphorylation may be required for the maximal induction of Stat1-mediated gene activation.

  1. Heim, M.H. (1999) J. Recept. Signal. Transduct. Res. 19, 75-120.
  2. Durbin, J.E. et al. (1996) Cell 84, 443-450.
  3. Meraz, M.A. et al. (1996) Cell 84, 431-442.
  4. Ihle, J.N. et al. (1994) Trends Biochem. Sci. 19, 222-227.
  5. Frank, D.A. (1999) Mol. Med. 5, 432-456.
  6. Wen, Z. et al. (1995) Cell 82, 241-250.

Application References

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Companion Products

For Research Use Only. Not For Use In Diagnostic Procedures.

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