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Redox regulation of Cdc25C
Pavel A Savitsky1, Toren Finkel
1Cardiovascular Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1622, USA.
The Journal of Biological Chemistry
|April 2, 2002
Summary
Oxidative stress degrades Cdc25C protein via disulfide bond formation, independent of Chk1. This degradation, involving specific cysteine residues, contributes to cell cycle arrest.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cdc25 phosphatases regulate cell cycle progression.
- Ultraviolet light triggers Cdc25A degradation via Chk1.
- The role of oxidative stress on Cdc25C stability was unclear.
Purpose of the Study:
- Investigate the effect of hydrogen peroxide on Cdc25A and Cdc25C levels.
- Determine the mechanism of Cdc25C degradation under oxidative stress.
- Examine the role of specific cysteine residues and disulfide bond formation in Cdc25C stability.
Main Methods:
- Cellular stress experiments with hydrogen peroxide.
- Pharmacological inhibition of Chk1.
- Site-directed mutagenesis of Cdc25C cysteine residues.
- In vitro and in vivo protein stability assays.
- Analysis of 14-3-3 binding.
Main Results:
- Hydrogen peroxide degrades Cdc25C, but not Cdc25A.
- Cdc25C degradation occurs independently of Chk1.
- Oxidative stress induces an intramolecular disulfide bond in Cdc25C.
- Mutations in active site cysteines (C330, C377) reduce Cdc25C stability.
- A double cysteine mutant (C2) is resistant to oxidative degradation and shows reduced 14-3-3 binding.
Conclusions:
- Oxidative stress induces Cdc25C degradation through disulfide bond formation.
- This degradation pathway is distinct from the Chk1-dependent pathway affecting Cdc25A.
- Cdc25C cysteine residues are critical for oxidative stress-induced degradation.
- Oxidative stress-mediated Cdc25C degradation contributes to cell cycle arrest.