Cell Signaling Technology

Product Pathways - PathScan ELISA

PathScan® Total HER3/ErbB3 Sandwich ELISA kit #7888

Kit Includes Volume Solution Color
HER3/ErbB3 Mouse Ab Coated Microwells 96 tests
HER3/ErbB3 Rabbit Detection Antibody 11 milliliters Green
Anti-rabbit IgG HRP-linked Ab 11 milliliters Red
TMB Substrate 11 milliliters Colorless
STOP Solution 11 milliliters Colorless
Sealing Tape 2 sheets
20X Wash Buffer 25 milliliters Colorless
Sample Diluent 25 milliliters Blue
Cell Lysis Buffer (10X) # 9803 15 milliliters Yellowish

Note: 12 8-well modules –Each module is designed to break apart for 8 tests.
Note: Kit should be stored at 4°C with the exception of Cell Lysis Buffer (10X), which is stored at –20°C (packaged separately).

Species Cross-Reactivity

H

Reactivity Key:  H=Human

Description

The PathScan® Total HER3/ErbB3 Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of HER3/ErbB3 protein. A HER3/ErbB3 mouse antibody has been coated on the microwells. After incubation with cell lysates, HER3/ErbB3 protein (phospho and nonphospho) is captured by the coated antibody. Following extensive washing, a HER3/ErbB3 rabbit antibody is added to detect captured HER3/ErbB3 protein. Anti-rabbit IgG, HRP-linked antibody is then used to recognize the bound detection antibody. HRP substrate TMB is added to develop color. The magnitude of the absorbance for this developed color is proportional to the quantity of HER3/ErbB3 protein.

Specificity / Sensitivity

PathScan® Total HER3/ErbB3 Sandwich ELISA Kit #7888 detects endogenous levels of total HER3/ErbB3 protein in human cells, as shown in Figure 1. The kit sensitivity is shown in Figure 2. This kit does not cross-react with other proteins of ErbB family (data not shown).

ELISA - Western correlation

ELISA - Western correlation

Figure 1: Constitutive phosphorylation of HER3/ErbB3 in Calu-3 cells lysed in the presence of phosphatase inhibitors* (phospho lysate) is detected by PathScan® Phospho-HER3/ErbB3 (panTyr) Sandwich ELISA Kit #7890 (top, right). In contrast, a low level of phospho-HER3/ErbB3 protein is detected in Calu-3 cells lysed in the absence of phosphatase inhibitors* (nonphospho lysate). Similar levels of total HER3/ErbB3 protein from both nonphospho or phospho lysates are detected by PathScan® Total HER3/ErbB3 Sandwich ELISA Kit #7888 (top, left). Absorbance at 450 nm is shown in the top figure while corresponding western blots using Phospho-HER3/ErbB3 (Tyr1289) Rabbit mAb #4791 (right) or a total HER3/ErbB3 Antibody #4754 (left) are shown in the bottom figure. *Phosphatase inhibitors include sodium pyrophosphate, β-glycerophosphate and Na3VO4.

Sensitivity

Sensitivity

Figure 2: The relationship between protein concentration of phospho or nonphospho lysates and the absorbance at 450 nm is shown. Unstarved Calu-3 cells were cultured (85% confluence) and lysed with or without the addition of phosphatase inhibitor to the lysis buffer (phospho or nonphospho lysate).

Background

HER3/ErbB3 is a member of the ErbB receptor protein tyrosine kinase family, but 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 PI3 kinase (4).ErbB3 is highly expressed in many cancer cells (5) and activation of the ErbB3/PI3 kinase pathway is correlated with malignant phenotypes of adenocarcinomas (6). 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, prevention of the interaction between ErbB3 and ErbB tyrosine kinases has become a novel anti-tumor strategy.

  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.

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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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