HER2 concentration (for cell types see comments section)

Range in mammary epithelial cells <10,000: in HB2 cells ~60,000 molecules/cell
Organism Human Homo sapiens
Reference Burke P, Schooler K, Wiley HS. Regulation of epidermal growth factor receptor signaling by endocytosis and intracellular trafficking. Mol Biol Cell. 2001 Jun12(6):1897-910. p.1905 right column bottom paragraphPubMed ID11408594
Primary Source Worthylake, R., Opresko, L.K., and Wiley, H.S. (1999). ErbB-2 amplification inhibits down-regulation and induces constitutive activation of both ErbB-2 and epidermal growth factor receptors. J. Biol. Chem. 274, 8865–8874.PubMed ID10085130
Method Abstract: "To directly evaluate EGFR [Epidermal Growth Factor Receptor] signaling during receptor trafficking, [investigators] developed a technique to rapidly and selectively isolate internalized EGFR and associated molecules with the use of reversibly biotinylated anti-EGFR antibodies. In addition, [they] developed antibodies specific to tyrosine-phosphorylated EGFR. With the use of a combination of fluorescence imaging and affinity precipitation approaches, [they] evaluated the state of EGFR activation and substrate association during trafficking in epithelial cells."
Comments P.1905 right column bottom paragraph: "The results obtained above (Figure 8) were obtained with HMEC (Human Mammary Epithelial Cells) displaying a basal phenotype (Taylor-Papadimitriou et al., 1989 blue right-pointing triangle). Although these cells are very responsive to EGF [Epidermal Growth Factor], they express very low levels of HER2 (<10,000 per cell Burke and Wiley, unpublished observations). Because HER2 is an important signaling component of the EGFR [EGF Receptor] system, [investigators] were interested in determining the location where EGFR and HER2 form heterodimers. For this analysis, [they] used HB2 cells, which are HMEC that have a pattern of keratin expression that is characteristic of a luminal phenotype (Bartek et al., 1991 blue right-pointing triangle). These cells express ∼60,000 HER2 molecules per cell (primary source, blue right-pointing triangle). [They] have previously shown that the trafficking of activated EGFR in HB2 cells is essentially identical to 184A1 cells (Burke and Wiley, 1999 blue right-pointing triangle)."
Entered by Uri M
ID 112721