Cell Signaling Technology

Product Pathways - Tyrosine Kinase / Adaptors

Phospho-HER3/ErbB3 (Tyr1222) (50C2) Rabbit mAb #4784

Applications Reactivity Sensitivity MW (kDa) Isotype
W H Endogenous 185 Rabbit IgG

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human
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-HER3/ErbB3 (Tyr1222) (50C2) Rabbit mAb detects endogenous HER3/ErbB3 proteins only when phosphorylated at tyrosine 1222. The antibody does not cross-react with other tyrosine phosphorylated receptor tyrosine kinases.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr1222 of human HER3/ErbB3.

Western Blotting

Western Blotting

Western blot analysis of MCF-7 and T47D cell lysates untreated or stimulated with Neuregulin (100 ng/ml) for 15 min, using Phospho-HER3/ErbB3 (Tyr1222) (50C2) Rabbit mAb (upper) and HER3/ErbB3 (1B2) Rabbit mAb #4754 (lower).

Background

HER3/ErbB3 is a member of the ErbB receptor protein tyrosine kinase family, but it lacks tyrosine kinase activity. Tyrosine phosphorylation of ErbB3 depends on its association with other ErbB tyrosine kinases. Upon ligand binding, heterodimers form between ErbB3 and other ErbB proteins, and ErbB3 is phosphorylated on tyrosine residues by the activated ErbB kinase (1,2). There are at least 9 potential tyrosine phosphorylation sites in the carboxy-terminal tail of ErbB3. These sites serve as consensus binding sites for signal transducing proteins, including Src family members, Grb2, and the p85 subunit of PI3 kinase, which mediate ErbB downstream signaling (3). Both Tyr1222 and Tyr1289 of ErbB3 reside within a YXXM motif and participate in signaling to PI3K (4).Investigators have found that ErbB3 is highly expressed in many cancer cells (5) and activation of the ErbB3/PI3K pathway is correlated with malignant phenotypes of adenocarcinomas (6). Research studies have demonstrated that in tumor development, ErbB3 may function as an oncogenic unit together with other ErbB members (e.g. ErbB2 requires ErbB3 to drive breast tumor cell proliferation) (7). Thus, investigators view inhibiting interaction between ErbB3 and ErbB tyrosine kinases as a novel strategy for anti-tumor therapy.

  1. Yarden, Y. and Sliwkowski, M.X. (2001) Nature Rev. Mol. Cell. Biol. 2, 127-137.
  2. Guy, P.M. et al. (1994) Proc. Natl. Acad. Sci. USA 91, 8132-8136.
  3. Songyang, Z. et al. (1993) Cell 72, 767-778.
  4. Kim, H.H. et al. (1994) J. Biol. Chem. 269, 24747-24755.
  5. Sithanandam, G. et al. (2003) Carcinogenesis 24, 1581-1592.
  6. Kobayashi, M. et al. (2003) Oncogene 22, 1294-1301.
  7. Holbro, T. et al. (2003) Proc. Natl. Acad. Sci. USA 100, 8933-8938.

Application References

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Companion Products

Rabbit Monoclonals Produced Using Epitomics® Technology, U.S. Patent No. 5,675,063.

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

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