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Related Concept Videos

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Affinity Precipitation of Active Rho-GEFs Using a GST-tagged Mutant Rho Protein GST-RhoAG17A from Epithelial Cell Lysates
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p115RhoGEF activates RhoA to support tight junction maintenance and remodeling.

Shahana A Chumki1, Lotte M van den Goor2, Benjamin N Hall2

  • 1Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109.

Molecular Biology of the Cell
|October 6, 2022
PubMed
Summary
This summary is machine-generated.

p115RhoGEF activates RhoA flares at tight junction leaks to repair epithelial barriers. This guanine nucleotide exchange factor is crucial for maintaining barrier integrity and directing cell junction remodeling.

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Area of Science:

  • Cell Biology
  • Epithelial Biology
  • Molecular Biology

Background:

  • Epithelial cell-cell junctions, specifically tight junctions (TJs), are essential for maintaining tissue barrier function.
  • Dynamic cell shape changes can lead to transient leaks in the TJ barrier.
  • RhoA activation, termed 'Rho flares,' repairs these leaks, but the upstream activators are unknown.

Purpose of the Study:

  • To identify the guanine nucleotide exchange factor (GEF) responsible for initiating RhoA activity at sites of TJ loss.
  • To elucidate the role of this GEF in Rho flare formation and TJ barrier repair.

Main Methods:

  • Investigated the localization and function of GEFs at TJs using knockdown experiments.
  • Assessed RhoA activity, TJ integrity, and actomyosin dynamics in response to GEF manipulation.
  • Monitored TJ barrier function and leak repair mechanisms.

Main Results:

  • p115RhoGEF was identified as the GEF that locally activates Rho flares at TJ leak sites.
  • Knockdown of p115RhoGEF reduced Rho flare intensity, impaired TJ remodeling, and decreased active RhoA levels.
  • p115RhoGEF deficiency compromised the apical actomyosin array and junctional complex integrity.
  • p115RhoGEF is essential for efficient local leak repair and TJ barrier maintenance.

Conclusions:

  • p115RhoGEF plays a critical role in activating junctional RhoA to preserve epithelial barrier function.
  • p115RhoGEF directs localized TJ remodeling and repair in response to barrier breaches.
  • This study reveals a key mechanism for maintaining epithelial integrity during cellular dynamic events.