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Updated: May 31, 2025

Author Spotlight: Developing Tools to Tune the Activity of Tyrosine Phosphatases
06:56

Author Spotlight: Developing Tools to Tune the Activity of Tyrosine Phosphatases

Published on: September 6, 2024

292

Talin, a Rap1 effector for integrin activation at the plasma membrane, also promotes Rap1 activity by disrupting

Zhongji Liao1, Sanford J Shattil1

  • 1Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.

Journal of Cell Science
|January 24, 2025
PubMed

Insights

Talin regulates cell adhesion and migration by interacting with integrins. This study reveals talin also activates Rap1 GTPase at the cell membrane, enhancing integrin function in endothelial cells.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Talin is crucial for cell adhesion and migration by modulating integrin affinity for extracellular matrix proteins.
  • This process in endothelial cells and platelets involves talin interacting with Rap1-GTP and the integrin β3 cytoplasmic tail.
  • Talin was previously identified as the Rap1-GTP effector for β3 integrin activation.

Purpose of the Study:

  • To investigate the detailed mechanism of talin's role in integrin activation.
  • To explore the interaction between talin, Rap1, and integrins using an optogenetic approach.
  • To elucidate the dual role of membrane-associated talin in regulating endothelial cell function.

Main Methods:

  • Utilized an optogenetic approach in living, immortalized endothelial cells.
  • Regulated the interaction of talin with the plasma membrane to study its effects.
  • Investigated Rap1 activation and integrin function in response to talin recruitment.

Main Results:

  • Optogenetic recruitment of talin to the plasma membrane induced localized Rap1 activation.
  • Talin appears to activate Rap1 by competing with SHANK3 for Rap1-GTP binding.
  • Rap1 activation by talin occurred at the cell periphery and within cellular protrusions.

Conclusions:

  • Membrane-associated talin plays a dual role in endothelial cell integrin regulation.
  • Talin releases Rap1-GTP from SHANK3 sequestration, thereby activating Rap1.
  • Talin acts as a key Rap1 effector, promoting integrin activation and thus cell adhesion and migration.
Keywords:
Endothelial cellOptogeneticsRap1SHANK3Talin

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