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Calmodulin regulates intracellular trafficking of epidermal growth factor receptor and the MAPK signaling pathway

Francesc Tebar1, Priam Villalonga, Tatiana Sorkina

  • 1Departament de Biologia Cel.lular, Facultat de Medicina, Institut d'Investigacions August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain 08036.

Molecular Biology of the Cell
|June 12, 2002
PubMed

Insights

Calmodulin regulates epidermal growth factor receptor (EGFR) signaling and trafficking. An antagonist, W-13, inhibits EGFR recycling and degradation, impacting MAPK signaling by interfering with Raf-1 activity.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Signal Transduction

Background:

  • Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor crucial for cellular processes.
  • EGFR is implicated in signal transduction, proliferation, and differentiation.
  • EGFR is also identified as a calmodulin-binding protein.

Purpose of the Study:

  • To investigate the role of calmodulin in regulating EGFR.
  • To analyze the effects of the calmodulin antagonist W-13 on EGFR intracellular trafficking and the MAPK signaling pathway.

Main Methods:

  • Treatment of cells with W-13, a calmodulin antagonist.
  • Analysis of EGFR internalization, recycling, and degradation.
  • Assessment of EGFR tyrosine phosphorylation and Shc protein recruitment.
  • Evaluation of MAPK signaling pathway activity, specifically Raf-1.
  • Use of metalloprotease inhibitor BB94 to investigate shedding.

Main Results:

  • W-13 inhibited EGFR recycling and degradation, leading to EGFR accumulation in endosomes.
  • W-13 stimulated EGFR tyrosine phosphorylation and Shc recruitment, potentially via CaM kinase II inhibition.
  • EGFR phosphorylation was blocked by BB94, suggesting shedding involvement.
  • W-13 decreased MAPK activity by interfering with Raf-1.

Conclusions:

  • Calmodulin plays a regulatory role in multiple steps of EGFR signaling and trafficking.
  • W-13 affects EGFR trafficking and signaling, highlighting calmodulin's importance.
  • The findings provide insights into the complex regulation of EGFR by calmodulin.

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