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Updated: Jul 14, 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

Switch-of-function mutants based on morphology classification of Ras superfamily small GTPases

Won Do Heo1, Tobias Meyer

  • 1Department of Molecular Pharmacology, Stanford University School of Medicine, 269 Campus Drive, Room 3215, Stanford, CA 94305, USA.

Cell
|May 7, 2003
PubMed

Insights

Researchers identified key amino acid positions in signaling proteins to switch their cellular functions. This discovery aids in understanding protein families and developing targeted therapies.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Protein Signaling

Background:

  • Signaling proteins within the same family can exhibit diverse cellular functions.
  • Understanding the determinants of this functional specificity is crucial for molecular biology and disease research.

Purpose of the Study:

  • To identify specific amino acid residues responsible for switching the functions of small GTPases.
  • To develop a predictive algorithm for creating switch-of-function mutants.

Main Methods:

  • Expression of 100 constitutively active human small GTPases to classify cell morphologies into distinct groups.
  • Development of a predictive algorithm to identify amino acid positions for functional switching.
  • Experimental validation of the algorithm by creating switch-of-function mutants for several small GTPases.

Main Results:

  • Expression of small GTPases resulted in nine distinct cell morphology classes.
  • The developed algorithm successfully predicted amino acid positions for functional switching.
  • Validated switch-of-function mutants were created for Rac1, CDC42, H-Ras, RalA, Rap2B, and R-Ras3.
  • Key residues for functional switching were often located outside known interaction surfaces and were structurally dispersed.

Conclusions:

  • Genome-wide functional classification combined with switch-of-function mutant generation is a powerful approach to explore protein family specificity.
  • The findings challenge existing notions about the location of residues governing protein function and specificity.

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