Related Experiment Video

Updated: Sep 2, 2025

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
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Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

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Afadin couples RAS GTPases to the polarity rheostat Scribble

Marilyn Goudreault1, Valérie Gagné1, Chang Hwa Jo1

  • 1Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, H3T 1J4, Canada.

Nature Communications
|August 5, 2022
PubMed

Insights

Afadin (AFDN) acts as a RAS effector, interacting with Scribble (SCRIB) to regulate cell contacts and polarity. This interaction impacts MAPK and PI3K signaling, affecting cell motility.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Afadin (AFDN) is crucial for cell-cell adhesion and polarity.
  • RAS GTPases are implicated in cell signaling, but their direct effectors are not fully understood.
  • The biological role of RAS complexing with AFDN remains unclear.

Purpose of the Study:

  • To investigate the interaction partners of AFDN isoforms.
  • To elucidate the functional consequences of AFDN-RAS interactions.
  • To understand the role of AFDN in RAS-mediated signaling and cell behavior.

Main Methods:

  • Proximity-based proteomics to map AFDN interaction networks.
  • Biochemical assays to characterize protein-protein interactions (e.g., PDZ-FHA domain interactions).
  • Gene knockout studies in epithelial cells to assess functional impacts.

Main Results:

  • Scribble (SCRIB), a polarity protein, was identified as a top AFDN interactor.
  • A direct, non-canonical interaction between SCRIB and AFDN was characterized.
  • AFDN interacts with RAS and RAP GTPases, with KRAS promoting AFDN-SCRIB complex formation.
  • Disruption of AFDN or SCRIB impaired MAPK and PI3K signaling kinetics and reduced cell motility.

Conclusions:

  • AFDN functions as a direct effector of RAS GTPases.
  • The AFDN-SCRIB complex is critical for regulating cell adhesion, polarity, and growth factor-dependent cell motility.
  • These findings explain defects in cell contacts and polarity observed in cells with activated RAS.

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