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The cell polarity regulator hScrib controls ERK activation through a KIM site-dependent interaction

K Nagasaka1, D Pim, P Massimi

  • 1International Centre for Genetic Engineering and Biotechnology, Area Science Park, Trieste, Italy. nagasaka@icgeb.org

Oncogene
|July 13, 2010
PubMed

Insights

Human Scribble (hScrib), a tumor suppressor, directly regulates extracellular signal-regulated kinase (ERK) signaling. Loss of hScrib elevates active ERK, promoting cancer progression.

Area of Science:

  • Cell Biology
  • Molecular Oncology
  • Signal Transduction

Background:

  • Human Scribble (hScrib) is a cell polarity regulator and potential tumor suppressor.
  • Loss of hScrib is associated with late-stage cancer development.
  • The precise mechanism of hScrib's tumor-suppressive function, particularly in cell signaling, is not fully understood.

Purpose of the Study:

  • To investigate the role of hScrib in regulating extracellular signal-regulated kinase (ERK) signaling.
  • To elucidate the molecular mechanisms by which hScrib interacts with and controls ERK activity.
  • To determine the functional consequences of hScrib-ERK interaction in cellular transformation.

Main Methods:

  • Utilized human keratinocytes to study hScrib and ERK interactions.
  • Employed techniques to assess phospho-ERK levels and nuclear translocation.
  • Investigated hScrib mutations, specifically targeting kinase interaction motif (KIM) docking sites.
  • Assessed the impact of hScrib on ERK activation and oncogenic Ras co-transforming activity.

Main Results:

  • hScrib directly regulates ERK signaling.
  • Loss of hScrib leads to increased phospho-ERK levels and nuclear translocation in keratinocytes.
  • hScrib interacts with ERK via two KIM docking sites, which are crucial for ERK-mediated hScrib phosphorylation.
  • Wild-type hScrib downregulates ERK activation and oncogenic Ras co-transforming activity, but a C-terminal KIM mutant lacks this function.

Conclusions:

  • hScrib acts as a direct negative regulator of ERK signaling through specific interaction domains.
  • The interaction between hScrib and ERK provides a mechanistic explanation for hScrib's tumor-suppressive activity.
  • Dysregulation of the hScrib-ERK pathway due to hScrib loss contributes to cancer progression.

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