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Divalent cations crosslink vimentin intermediate filament tail domains to regulate network mechanics
Yi-Chia Lin1, Chase P Broedersz, Amy C Rowat
1Department of Physics, Harvard University, Pierce 231, 29 Oxford Street, Cambridge, MA 02138, USA.
Journal of Molecular Biology
|May 8, 2010
Summary
Divalent cations like Ca(2+) and Mg(2+) crosslink vimentin intermediate filament networks, influencing cellular mechanical integrity. This study elucidates their role in network elasticity and identifies specific protein regions mediating this crucial interaction.
Area of Science:
- Cell Biology
- Biophysics
- Materials Science
Background:
- Intermediate filament networks are vital for cell mechanical integrity.
- The crosslinking mechanisms and mechanical properties of these networks remain poorly understood.
Purpose of the Study:
- To investigate the role of divalent cations in crosslinking vimentin intermediate filament networks.
- To elucidate the origins of the mechanical properties of vimentin networks.
Main Methods:
- Rheological experiments were performed on in vitro vimentin networks.
- Vimentin variants with truncated C-terminal tails were used to identify crosslinking regions.
- A theoretical framework was applied to describe network elastic response.
Main Results:
- Divalent cations (Ca(2+), Mg(2+)) were identified as crosslinkers, stiffening vimentin networks.
- Network elasticity exhibits nonlinear behavior explained by entropic and enthalpic contributions.
- The C-terminal tail domain, specifically the last 11 amino acids, mediates divalent ion crosslinking.
Conclusions:
- Divalent cations play a significant role in crosslinking vimentin networks.
- Understanding this crosslinking mechanism provides insight into cytoskeletal mechanics.
- Divalent ions may regulate cellular structure and mechanical properties.
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