Cell Signaling Technology

Product Pathways - Tyrosine Kinase / Adaptors

Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb #2243

Applications Reactivity Sensitivity MW (kDa) Isotype
W IHC-P IHC-F H Endogenous 185 Rabbit IgG

Applications Key:  W=Western Blotting  IHC-P=Immunohistochemistry (Paraffin)  IHC-F=Immunohistochemistry (Frozen)
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-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb detects endogenous levels of ErbB2 only when phosphorylated at tyrosines 1221/1222. The antibody does not detect other activated Erb family members or other tyrosine-phosphorylated proteins.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding tyrosines 1221/1222 of human ErbB2 protein.

Western Blotting

Western Blotting

Western blot analysis of extracts from cells expressing different activated tyrosine kinase proteins, using Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb (upper) or Phospho-Tyrosine mAb (P-Tyr-100) #9411 (lower). Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb specifically detects phosphorylated HER2/ErbB2 but not other phosphorylated tyrosine kinases.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human breast carcinoma, showing membrane localization, using Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb.

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded SkBr3 cell pellets untreated (left) EGF-treated (right) either untreated (top) or lambda-phosphatase-treated (bottom), using Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb.


IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human renal adenocarcinoma, using Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb in the presence of control peptide (left) or Phospho-HER2/ErbB2 (Tyr1221/1222) Blocking Peptide #1254 (right).

IHC-P (paraffin)

IHC-P (paraffin)

Immunohistochemical analysis of paraffin-embedded human NCI-H358 xenograft, using Phospho-HER2/ErbB2 (Tyr1221/1222) (6B12) Rabbit mAb.

IHC-F (frozen)

IHC-F (frozen)

Immunohistochemical analysis of frozen HCC827 xenograft, using Phospho-Her2/ErbB2 (Tyr1221/1222)(6B12) Rabbit mAb.


Background

The ErbB2 (HER2) proto-oncogene encodes a 185 kDa transmembrane, receptor-like glycoprotein with intrinsic tyrosine kinase activity (1). While ErbB2 lacks an identified ligand, ErbB2 kinase activity can be activated in the absence of a ligand when overexpressed and through heteromeric associations with other ErbB family members (2). Amplification of the ErbB2 gene and overexpression of its product are detected in almost 40% of human breast cancers (3). Binding of the c-Cbl ubiquitin ligase to ErbB2 at Tyr1112 leads to ErbB2 poly-ubiquitination and enhances degradation of this kinase (4). ErbB2 is a key therapeutic target in the treatment of breast cancer and other carcinomas and targeting the regulation of ErbB2 degradation by the c-Cbl-regulated proteolytic pathway is one potential therapeutic strategy. Phosphorylation of the kinase domain residue Tyr877 of ErbB2 (homologous to Tyr416 of pp60c-Src) may be involved in regulating ErbB2 biological activity. The major autophosphorylation sites in ErbB2 are Tyr1248 and Tyr1221/1222; phosphorylation of these sites couples ErbB2 to the Ras-Raf-MAP kinase signal transduction pathway (1,5).

  1. Muthuswamy, S.K. et al. (1999) Mol Cell Biol 19, 6845-57.
  2. Qian, X. et al. (1994) Proc Natl Acad Sci USA 91, 1500-4.
  3. Dittadi, R. and Gion, M. (2000) J Natl Cancer Inst 92, 1443-4.
  4. Klapper, L.N. et al. (2000) Cancer Res 60, 3384-8.
  5. Kwon, Y.K. et al. (1997) J Neurosci 17, 8293-9.

Application References

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Companion Products

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

This product is intended for research purposes only. The product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

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