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Updated: Aug 19, 2026

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

The unique N-terminus of R-ras is required for Rac activation and precise regulation of cell migration

Stephen P Holly1, Mark K Larson, Leslie V Parise

  • 1Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.

Molecular Biology of the Cell
|March 18, 2005
PubMed

Insights

The unique N-terminus of R-Ras protein positively regulates Rac activation and cell spreading but negatively impacts cell migration. This finding clarifies R-Ras

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Ras family GTPases, including R-Ras, regulate crucial integrin-dependent cellular functions like adhesion, spreading, and migration.
  • Oncogenic Ras GTPases and R-Ras share sequence homology but induce distinct cellular behaviors, suggesting unique regulatory mechanisms.

Purpose of the Study:

  • To investigate the structural basis for R-Ras-specific signaling.
  • To determine if the unique N-terminal 26 amino acid extension of R-Ras is responsible for its distinct cellular functions.

Main Methods:

  • Utilized a 32D mouse myeloid cell line.
  • Compared the signaling activities of full-length R-Ras and a truncated version lacking the N-terminal 26 amino acids.

Main Results:

  • Full-length R-Ras activated Rac, leading to cell spreading, while truncated R-Ras did not activate Rac and showed reduced spreading.
  • Truncated R-Ras exhibited increased beta3 integrin-dependent cell migration compared to full-length R-Ras.
  • Subcellular localization and cell adhesion were unaffected by the N-terminal extension.

Conclusions:

  • The N-terminus of R-Ras positively regulates Rac activation and cell spreading.
  • The N-terminus of R-Ras negatively regulates R-Ras-mediated cell migration.
  • The N-terminal extension dictates specific R-Ras functions, differentiating its signaling pathways from other Ras GTPases.

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