Molecular Insight into the Regulation of Vimentin by Cysteine Modifications and Zinc Binding

Area of Science:

• Biochemistry
• Cell Biology
• Structural Biology

Background:

• Vimentin, an intermediate filament protein, is crucial for cellular processes and disease.
• Oxidative stress significantly reorganizes vimentin, with Cys328 modifications playing a key role.
• The precise molecular mechanisms of vimentin regulation by zinc remain unclear.

Purpose of the Study:

• To elucidate the molecular basis of vimentin regulation by zinc availability.
• To investigate the role of Cys328 in vimentin's response to oxidative stress and zinc.
• To understand how zinc binding affects vimentin structure and reactivity.

Main Methods:

• In vitro alkylation and oxidation assays.
• Combined oxidation and crosslinking experiments.
• Molecular dynamics simulations.
• Computational modeling of vimentin conformations.

Main Results:

• Cys328 exhibits low pKa, indicating high reactivity, and readily undergoes oxidation and alkylation.
• Zinc ions bind to the thiolate form of Cys328, stabilized by Glu329 and Asp331.
• Micromolar zinc concentrations inhibit Cys328 alkylation, lipoxidation, and disulfide formation.
• Zinc selectively protects vimentin from cysteine-reactive crosslinking agents, unlike magnesium.
• Computational models support Cys328 proximity in certain vimentin conformations, enabling disulfide crosslinking.

Conclusions:

• The Cys328 region is a critical zinc-binding hotspot modulating vimentin reactivity.
• Zinc availability dynamically regulates vimentin's response to oxidative stress via Cys328.
• These findings offer a molecular perspective on vimentin regulation and potential drug targeting.