Cell Signaling Technology

Product Pathways - Tyrosine Kinase/ Adaptors

HER2/ErbB2 (44E7) Mouse mAb #2248

Applications Reactivity MW (kDa) Source Isotype
W H 185 Mouse IgG1

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

HER2/ErbB2 (44E7) Mouse mAb detects endogenous levels of Her2/ErbB2 in various cell lines. It does not cross-react with any other related proteins.

Source / Purification

Monoclonal antibody is produced by immunizing mice with a synthetic peptide (KLH-coupled) corresponding to residues close to the carboxy-terminal sequence of human Her2/ErbB2.

Western Blotting

Western Blotting

Western blot analysis of various cell lysates using HER2/ErbB2 (44E7) Mouse mAb. HER2/ErbB2 (44E7) Mouse mAb specifically recognizes Her2/ErbB2 in SK-BR-3, MDA-MB-453 and T47D cells, but does not cross-react with EGF receptors (ovexpressed in A431 cells), ErbB3 (overexpressed in Cos-7 cells), or ErbB4 (overexpressed in CEM cells). ( The CEM-ErbB4 cell lysate was provided by Dr. David Riese, Purdue University).

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 with the regulation of ErbB2 degradation by the c-Cbl-regulated proteolytic pathway as 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 areTyr1248 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, 6845-6857.
  2. Qian, X. et al. (1994) Proc. Natl. Acad. Sci. USA 91, 1500-1504.
  3. Dittadi, R. and Gion, M. (2000) J. Natl. Cancer Inst. 92, 1443-1444.
  4. Klapper, L.N. et al. (2000) Cancer Res. 60, 3384-3388.
  5. Kwon, Y.K. et al. (1997) J. Neurosci. 17, 8293-8299.

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