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The interaction of Ras with GTPase-activating proteins
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
Summary
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.