Phospho-HER2/ErbB2 Antibody Sampler Kit #9923

Protocols

• 2243: Western Blotting, Immunohistochemistry (Paraffin), Immunohistochemistry (Frozen)
• 2247: Western Blotting
• 4290: Western Blotting, Immunohistochemistry (Paraffin)
• 7074: Western Blotting

The Phospho-HER2/ErbB2 Antibody Sampler Kit provides an economical means to evaluate the activation status of HER2/ErbB2, including the phosphorylation of Tyr1248 and Tyr1221/1222. The control HER2/ErbB2 antibody is also included. The kit contains enough primary antibodies to perform two Western blot experiments per primary antibody.

Each phospho-HER2/ErbB2 antibody recognizes only the phosphorylated form of HER2/ErbB2 at the indicated sites. The control HER2/ErbB2 receptor antibody recognizes both phosphorylated and nonphosphorylated forms of HER2/ErbB2.

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr1248. Polyclonal antibodies are purified by protein A and peptide affinity chromatography. Monoclonal antibodies are produced by immunizing animals with synthetic peptides corresponding to residues surrounding tyrosines 1221/1222 and residues near the amino terminus of human ErbB2 protein.

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 U S A 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.

Data sheet (105KB)