Cell Signaling Technology

Product Pathways - Jak/Stat Pathway

Phospho-Stat3 (Tyr705) Blocking Peptide #1195

Description

This peptide is used to block Phospho-Stat3 (Tyr705) (D3A7) rabbit mAb #9145, Phospho-Stat3 (Tyr705) Antibody #9131, and Phospho-Stat3 (Tyr705) (3E2) mouse mAb #9138 reactivity.

Quality Control

The quality of the peptide was evaluated by reversed-phase HPLC and by mass spectrometry. The peptide blocks Phospho-Stat3 (Tyr705) (DA37) Rabbit mAb # 9145 by immunohistochemistry and western blotting and Phospho-Stat3 (Tyr705) Antibody # 9131 and Phospho-Stat3 (Tyr705) (3E2) Mouse mAb # 9138 signal by western blotting.

Western Blotting

Western Blotting

Western Blot analysis of extracts from serum starved HeLa cells, untreated or IFN-alpha-treated (100 ng/ml for 5 minutes), using a variety of Phospho-Stat3 and Stat 3 antibodies. The upper panels show the antibody pre-incubated with the blocking peptide while the lower panels have no blocking peptide added.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human colon carcinoma, using Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb #9145 in the presence of control peptide (left) or Phospho-Stat3 (Tyr705) Blocking Peptide (right).

Applications

Use as a blocking reagent to evaluate the specificity of antibody reactivity in western immunoblotting and immunohistochemistry protocols.

Directions for Use

For immunohistochemistry, add twice the volume of peptide as volume of antibody used in 100 μl total volume. Incubate for a minimum of 30 minutes prior to adding the entire volume to the slide. Recommended antibody dilutions can be found on the product data sheet.

For Western immunoblotting, add 10 µl of antibody and 10 µl of blocking peptide to 10 ml of antibody dilution buffer, and incubate at room

temperature for 30 minutes before allowing to react with the blot.

Background

The Stat3 transcription factor is an important signaling molecule for many cytokines and growth-factor receptors (1) and is required for murine fetal development (2). Stat3 is constitutively activated in a number of human tumors (3,4) and possesses oncogenic potential (5) and anti-apoptotic activities (3). Stat3 is activated by phosphorylation at Tyr705, which induces dimerization, nuclear translocation and DNA binding (6,7). Transcriptional activation seems to be regulated by phosphorylation at Ser727 through the MAPK or mTOR pathways (8,9). Stat3 isoform expression appears to reflect biological function as the relative expression levels of Stat3α (86 kDa) and Stat3β (79 kDa) depend on cell type, ligand exposure or cell maturation stage (10). It is notable that Stat3β lacks the serine phosphorylation site within the carboxy-terminal transcriptional activation domain (8).

  1. Heim, M.H. (1999) J. Recept. Signal Transduct. Res. 19, 75-120.
  2. Takeda, K. et al. (1997) Proc. Natl. Acad. Sci. USA 94, 3801-3804.
  3. Catlett-Falcone, R. et al. (1999) Immunity 10, 105-115.
  4. Garcia, R. and Jove, R. (1998) J. Biomed. Sci. 5, 79-85.
  5. Bromberg, J.F. et al. (1999) Cell 98, 295-303.
  6. Darnell Jr., J.E. et al. (1994) Science 264, 1415-1421.
  7. Ihle, J.N. (1995) Nature 377, 591-594.
  8. Wen, Z. et al. (1995) Cell 82, 241-250.
  9. Yokogami, K. et al. (2000) Curr. Biol. 10, 47-50.
  10. Biethahn, S. et al. (1999) Exp. Hematol. 27, 885-894.

Application References

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Companion Products

This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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