no pathway map

News from the Bench

Discover what’s going on at CST, receive our latest application notes and tips, read our science features, and learn about our products.


Antibody Guarantee

CST Antibody Performance Guarantee



Find answers on our FAQs page.


Visit PhosphoSitePlus®

PTM information and tools available.


Order Details

Custom Ordering Details: The control slides that accompany this kit are cut freshly upon ordering. Please allow three to five days for your order to be processed and shipped.

Product Description

The SignalStain® Phospho-Stat IHC Sampler Kit from Cell Signaling Technology allows the researcher to examine paraffin-embedded tissues or cells with antibodies that will detect phosphorylated Stat proteins. Each antibody is validated for use in immunohistochemical assays using multiple approaches. Also included in the kit are control slides that can be used to verify the performance of each antibody and a primary antibody diluent. Please see table above for the recommended antibody diluent for each antibody provided in the kit.

Specificity / Sensitivity

Each antibody in the SignalStain® Phospho-Stat IHC Sampler Kit detects endogenous levels of its target protein. Phospho-Stat1 (Tyr701) (58D6) Rabbit mAb detects endogenous levels of Stat1 only when phosphorylated at Tyr701; p91 Stat1 phosphorylated at Tyr701 and the p84 splice variant will also be detected by this antibody. It does not cross-react with the corresponding phospho-tyrosines of other Stat proteins. Phospho-Stat3 (Tyr705) (D3A7) XP® Rabbit mAb 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. Phospho-Stat5 (Tyr694) (C11C5) Rabbit mAb detects endogenous Stat5a only when phosphorylated at Tyr694 and Stat5b when phosphorylated at Tyr699.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr701 of human Stat1, Tyr705 of mouse Stat3, or Tyr694 of Stat5a.

Stat proteins serve as transcription factors in growth and survival pathways stimulated by growth factor and cytokine activation of receptor proteins. Receptor activation promotes tyrosine phosphorylation of Stat proteins, resulting in Stat dimerization and translocation to the nucleus where they regulate expression of numerous proteins that control cell growth, survival, differentiation and pathogen resistance (1). Stat1 is essential in IFN-α and IFN-γ stimulated pathways and is abnormally activated in many tumors (2,3). Both Stat1α (91 kDa) and Stat1β (84 kDa) isoforms are activated by IFN-α but only Stat1α responds to IFN-γ. Phosphorylation of Stat1 at Tyr701 induces Stat1 dimerization, nuclear translocation and DNA binding (4). Transcription factor Stat3 possesses oncogenic potential and anti-apoptotic activities; a number of human tumors display constitutively activated Stat3 (5,6). Activation of Stat3 follows phosphorylation at Tyr705, resulting in dimerization, nuclear translocation and DNA binding (7). Expression of Stat3α (86 kDa) and Stat3β (79 kDa) isoforms correlates with cell type, ligand and cell maturation stage (8). Phosphorylation of Stat5a at Tyr694 is essential for transcription factor activation (9). Stat5 is activated by interleukins and other cytokines (i.e. CSF1); presence of phosphorylated Stat5 is in some IL-3-treated cells suggests a role in angiogenesis and cell motility (10). Altered Stat5 expression and activity is associated with abnormal cell proliferation and apoptosis in some forms of leukemia (11).

1.  Ihle, J.N. (2001) Curr Opin Cell Biol 13, 211-7.

2.  Bromberg, J. (2002) J Clin Invest 109, 1139-42.

3.  Darnell, J.E. (1997) Science 277, 1630-5.

4.  Catlett-Falcone, R. et al. (1999) Immunity 10, 105-15.

5.  Ihle, J.N. et al. (1994) Trends Biochem. Sci. 19, 222-227.

6.  Garcia, R. and Jove, R. (1998) J Biomed Sci 5, 79-85.

7.  Gouilleux, F. et al. (1994) EMBO J 13, 4361-9.

8.  Biethahn, S. et al. (1999) Exp Hematol 27, 885-94.

9.  Buitenhuis, M. et al. (2004) Int J Biochem Cell Biol 36, 2120-4.

10.  Frank, D.A. (1999) Mol. Med. 5, 432-456.

11.  Baśkiewicz-Masiuk, M. et al. (2003) Cell Prolif 36, 265-78.

For Research Use Only. Not For Use In Diagnostic Procedures.
Cell Signaling Technology® is a trademark of Cell Signaling Technology, Inc.
SignalStain® is a trademark of Cell Signaling Technology, Inc.
U.S. Patent No. 5,675,063.