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Ligand-induced conformational changes in villin, a calcium-controlled actin-modulating protein
The Journal of Biological Chemistry
|January 10, 1983
Summary
Calcium binding induces a significant conformational change in villin, altering its structure and function as an actin filament regulator. This structural shift is crucial for its role in microvillus stability and calcium-mediated disassembly.
Area of Science:
- Biochemistry
- Structural Biology
- Cell Biology
Background:
- Villin is a calcium-modulated protein regulating actin filament organization.
- Actin filament dynamics are critical for cellular structure and function, particularly in microvilli.
Purpose of the Study:
- To investigate the structural changes of villin in response to calcium binding.
- To elucidate the role of the villin headpiece domain in calcium-induced conformational changes.
Main Methods:
- Analytical ultracentrifugation
- Gel chromatography
- Ultraviolet difference spectroscopy
- Circular dichroism
Main Results:
- Villin undergoes a conformational change upon calcium binding, indicated by altered sedimentation coefficients and Stokes radii.
- Calcium binding increases villin's asymmetry and length, suggesting a more extended conformation.
- The villin headpiece domain is essential for this calcium-induced structural transition.
Conclusions:
- Villin acts as a cross-linker in microvillus core filaments, and its structure is dynamically regulated by calcium.
- Calcium-mediated structural changes in villin lead to the disintegration of microvillus core filament bundles.