The interaction of Ras with GTPase-activating proteins

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Comparing the Affinity of GTPase-binding Proteins using Competition Assays
10:37

Comparing the Affinity of GTPase-binding Proteins using Competition Assays

Published on: October 8, 2015

A Wittinghofer1, K Scheffzek, M R Ahmadian

  • 1Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany. alfred.wittinghofer@mpi-dortmund.mpg.de

FEBS Letters
|June 23, 1997
PubMed

Insights

GTPase-activating proteins (GAPs) regulate Ras signaling by accelerating GTP hydrolysis. Recent findings suggest GAPs stabilize the transition state, enhancing the Ras GTPase reaction crucial for cell growth.

Area of Science:

  • Molecular biology
  • Biochemistry
  • Cell signaling

Background:

  • Ras proteins function as molecular switches in signal transduction pathways controlling cell growth and differentiation.
  • The GTPase activity of Ras is critical for terminating Ras-effector interactions.
  • GTPase-activating proteins (GAPs) are negative regulators that accelerate Ras GTP hydrolysis.

Purpose of the Study:

  • To review recent biochemical and structural findings on the mechanism of GAP action.
  • To strengthen the hypothesis regarding GAP's role in accelerating the Ras GTPase reaction.

Main Methods:

  • Biochemical assays to study GTP hydrolysis rates.
  • Structural biology techniques to elucidate protein-protein interactions and conformational changes.
  • Review of existing literature on Ras-GAP interactions.

Main Results:

  • GTP hydrolysis of oncogenic Ras mutants is not altered.
  • Recent findings support the hypothesis that GAPs accelerate the GTP cleavage step.
  • GAP action involves stabilizing the transition state of the phosphoryl transfer reaction.

Conclusions:

  • GAPs are key regulators of Ras signaling by enhancing the GTPase reaction.
  • The mechanism of GAP action involves transition state stabilization.
  • Understanding GAP mechanisms provides insights into cell growth and differentiation control.

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