Cell Signaling Technology

Product Pathways - Jak/Stat Pathway

Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb (Alexa Fluor® 647 Conjugate) #4324

Applications Reactivity Sensitivity Isotype
F H M Endogenous Rabbit IgG

Applications Key:  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse
Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb (Alexa Fluor® 647 Conjugate) detects endogenous levels of Stat3 only when phosphorylated at Tyr705. This antibody does not cross-react with phospho-EGFR or with corresponding phospho-tyrosines of other Stat proteins.

Source / Purification

Monoclonal antibody is produced by immunizing rabbits with a synthetic phosphopeptide (KLH-coupled) corresponding to residues surrounding Tyr705 of mouse Stat3. The antibody was conjugated to Alexa Fluor® 647 under optimal conditions with an F/P ratio of 2-5. The Alexa Fluor® 647 dye is maximally excited by red light (e.g. 633 nm He-Ne laser). Antibody conjugates of the Alexa Fluor® 647 dye produce bright far-red-fluorescence emission with a peak at 665 nm.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of Jurkat cells, untreated (blue) or IFN-α treated (green), using Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb (Alexa Fluor® 647 Conjugate).

Description

This Cell Signaling Technology antibody is conjugated to Alexa Fluor ® 647 fluorescent dye and tested in-house for direct flow cytometric analysis of human cells. The unconjugated antibody, #9145, reacts with Phospho-Stat3 (Tyr705) from human and mouse. CST expects that Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb (Alexa Fluor® 647 Conjugate) will also recognize Phospho-Stat3 in these species.

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

Alexa Fluor® is a registered trademark of Molecular Probes, Inc.

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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