Related Experiment Video

Updated: Sep 18, 2025

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

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Rap1 activity and localization is regulated by Rab40/CRL5 facilitated mono-ubiquitylation

Andrew Neumann1, Revathi Sampath1, Ke-Jun Han1

  • 1Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States.

Micropublication Biology
|June 25, 2025
PubMed

Insights

Rab40/CRL5 E3 ubiquitin ligase complex mono-ubiquitylates Rap1, a GTPase crucial for cell migration. This modification is essential for Rap1

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Rap GTPases regulate actin dynamics and cell migration.
  • Mechanisms of Rap GTPase activation and localization are not fully understood.
  • Rab40/CRL5-dependent mono-ubiquitylation regulates Rap2 activation.

Purpose of the Study:

  • To investigate the role of mono-ubiquitylation in Rap1 regulation.
  • To determine if Rab40/CRL5 targets Rap1 for ubiquitylation.
  • To elucidate the impact of Rap1 mono-ubiquitylation on its localization and activity.

Main Methods:

  • Ubiquitylation assays
  • Immunoprecipitation
  • Confocal microscopy
  • Western blotting

Main Results:

  • Rap1 undergoes mono-ubiquitylation mediated by a Rab40/CRL5 E3 ubiquitin ligase complex.
  • Rap1 mono-ubiquitylation is essential for its proper localization to the plasma membrane and nuclear envelope.
  • This finding extends the role of Rab40/CRL5 to the regulation of Rap1 activity and dynamics.

Conclusions:

  • Rab40/CRL5 is a key regulator of Rap GTPase family members, including Rap1.
  • Mono-ubiquitylation by Rab40/CRL5 controls Rap1's spatiotemporal dynamics and subcellular localization.
  • This study provides novel insights into the post-translational regulation of Rap GTPases.

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