Cell Signaling Technology
XP Monoclonal Antibody

Product Pathways - Jak/Stat Pathway

Phospho-Stat3 (Tyr705) (D3A7) XP® Rabbit mAb (Alexa Fluor® 488 Conjugate) #4323

Applications Reactivity MW (kDa) Isotype
F H M R Mk (Hm) (B) (Pg) (Hr) 86 kDa Rabbit IgG

Applications Key:  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat  Hm=Hamster  Mk=Monkey  B=Bovine  Pg=Pig  Hr=Horse
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-Stat3 (Tyr705) (D3A7) XP® Rabbit mAb (Alexa Fluor® 488 Conjugate) detects endogenous levels of Stat3 only when phosphorylated at Tyr705. This antibody does not cross-react with phospho-EGFR or the corresponding phospho-tyrosines of other Stat proteins.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr705 of mouse Stat3. The antibody was conjugated to Alexa Fluor® 488 under optimal conditions with an F/P ratio of 2-6.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of Jurkat cells, untreated (blue) or IFN-α treated (green), using Phospho-Stat3 (Tyr705) (D3A7) XP® Rabbit mAb (Alexa Fluor® 488 Conjugate) #4323 compared to nonspecific control antibody (red).

Description

This Cell Signaling Technology antibody conjugated to Alexa Fluor® 488 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, mouse and rat. CST expects that Phospho-Stat3 (Tyr705) (D3A7) XP® Rabbit mAb (Alexa Fluor® 488 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). Research studies have shown that 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. (2001) J Recept Signal Transduct Res 19, 75-120.
  2. Takeda, K. et al. (1997) Proc Natl Acad Sci U S A 94, 3801-4.
  3. Catlett-Falcone, R. et al. (1999) Immunity 10, 105-15.
  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, J.E. et al. (1994) Science 264, 1415-21.
  7. Ihle, J.N. (1995) Nature 377, 591-4.
  8. Wen, Z. et al. (1995) Cell 82, 241-50.
  9. Yokogami, K. et al. (2000) Curr Biol 10, 47-50.
  10. Biethahn, S. et al. (1999) Exp Hematol 27, 885-94.

Application References

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Companion Products

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

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