Cell Signaling Technology

Product Pathways - Tyrosine Kinase/ Adaptors

Phospho-EGF Receptor (Tyr998) (C24A5) Rabbit mAb #2641

Applications Reactivity Sensitivity MW (kDa) Isotype
W IP H Endogenous 175 Rabbit IgG

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
Reactivity Key:  H=Human
Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-EGF Receptor (Tyr998) (C24A5) Rabbit mAb detects endogenous levels of EGF receptor only when phosphorylated at Tyr998. This antibody may weakly cross-react with other tyrosine-phosphorylated proteins.

Source / Purification

Monoclonal antibodies are produced by immunizing rabbits with a synthetic phosphopeptide (KLH-coupled) corresponding to residues surrounding Tyr998 of human EGF receptor.

Western Blotting

Western Blotting

Western blot analysis of extracts from A431 and BxPC-3 cells, untreated or treated with EGF, using Phospho-EGF Receptor (Tyr998) (C24A5) Rabbit mAb (upper) and EGF Receptor Antibody #2232 (lower).

Background

The epidermal growth factor (EGF) receptor is a 170 kDa transmembrane tyrosine kinase that belongs to the HER/ErbB protein family. Ligand binding results in receptor dimerization, autophosphorylation, activation of downstream signaling and lysosomal degradation (1,2). Phosphorylation of EGF receptor (EGFR) at Tyr845 in the kinase domain is implicated in stabilizing the activation loop, maintaining the active state enzyme and providing a binding surface for substrate proteins (3,4). c-Src is involved in phosphorylation of EGFR at Tyr845 (5). The SH2 domain of PLCγ binds at phospho-Tyr992, resulting in activation of PLCγ-mediated downstream signaling (6). Phosphorylation of EGFR at Tyr1045 creates a major docking site for c-Cbl, an adaptor protein that leads to receptor ubiquitination and degradation following EGFR activation (7,8). The GRB2 adaptor protein binds activated EGFR at phospho-Tyr1068 (9). A pair of phosphorylated residues (Tyr1148 and Tyr1173) provides a docking site for the SHC scaffold protein, with both sites involved in MAP kinase signaling activation (2). Phosphorylation of EGFR at specific serine and threonine residues attenuates EGFR kinase activity. EGFR carboxy-terminal residues Ser1046 and Ser1047 are phosphorylated by CaM kinase II; mutations to either of these serines results in upregulated EGFR tyrosine autophosphorylation (10).

Phosphorylation of EGF receptor on Tyr998 was identified at Cell Signaling Technology (CST) using PhosphoScan®, CST's LC-MS/MS platform for phosphorylation site discovery as well as another publication using MS technology (11). Phosphorylation of EGF receptor at Tyr998 was observed in select carcinoma cell lines and in tumors.

  1. Hackel, P.O. et al. (1999) Curr. Opin. Cell Biol. 11, 184-189.
  2. Zwick, E. et al. (1999) Trends Pharmacol. Sci. 20, 408-412.
  3. Cooper, J.A. and Howell, B. (1993) Cell 73, 1051-1054.
  4. Hubbard, S.R. et al. (1994) Nature 372, 746-754.
  5. Biscardi, J.S. et al. (1999) J. Biol. Chem. 274, 8335-8343.
  6. Emlet, D.R. et al. (1997) J. Biol. Chem. 272, 4079-4086.
  7. Levkowitz, G. et al. (1999) Mol. Cell 4, 1029-1040.
  8. Ettenberg, S.A. et al. (1999) Oncogene 18, 1855-1866.
  9. Rojas, M. et al. (1996) J. Biol. Chem. 271, 27456-27461.
  10. Feinmesser, R.L. et al. (1999) J. Biol. Chem. 274, 16168-16173.
  11. Wolf-Yadlin, A. et al. (2007) Proc. Natl. Acad. Sci. USA 104, 5860-5865.

Application References

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This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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