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Negative regulation of HER2 signaling by the PEST-type protein-tyrosine phosphatase BDP1

Miriam Gensler1, Marcus Buschbeck, Axel Ullrich

  • 1Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried, Germany.

The Journal of Biological Chemistry
|December 9, 2003
PubMed

Insights

The protein-tyrosine phosphatase BDP1 regulates HER2 signaling. BDP1 suppresses HER2 activity, impacting downstream pathways and potentially breast cancer progression.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Biochemistry

Background:

  • Receptor tyrosine kinases (RTKs) control cellular functions; dysregulation is linked to disease.
  • Tight control of RTK activity is essential for cellular homeostasis.
  • HER2, an epidermal growth factor receptor (EGFR) family member, plays a role in various cellular processes.

Purpose of the Study:

  • To investigate the regulatory role of the PEST-type protein-tyrosine phosphatase BDP1 in HER2 signaling.
  • To determine if BDP1 affects HER2 activation and downstream pathways.
  • To explore the potential involvement of BDP1 in HER2-related pathophysiological conditions, such as breast cancer.

Main Methods:

  • Investigated BDP1's effect on ligand-induced HER2 activation.
  • Assessed the impact of BDP1 overexpression and suppression on HER2 phosphorylation.
  • Examined BDP1's influence on downstream signaling components, including Gab1 and mitogen-activated protein kinase (MAPK).
  • Analyzed BDP1 and HER2 coexpression in breast cancer cells.

Main Results:

  • HER2 signaling demonstrates high sensitivity to BDP1 activity.
  • BDP1 overexpression inhibited ligand-induced HER2 activation, but not EGFR activation.
  • Suppression of endogenous BDP1 increased HER2 phosphorylation.
  • BDP1 interfered with downstream signaling by inhibiting Gab1 phosphorylation and reducing MAPK activation.
  • BDP1 is coexpressed with HER2 in breast cancer cells.

Conclusions:

  • BDP1 acts as a significant regulator of HER2 activity.
  • This study identifies BDP1 as the first protein-tyrosine phosphatase involved in attenuating HER2 signaling.
  • BDP1's role in HER2 regulation suggests its potential involvement in breast cancer pathogenesis.

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