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The structure of Aip1p, a WD repeat protein that regulates Cofilin-mediated actin depolymerization
Walter C Voegtli1, A Yarrow Madrona, David K Wilson
1Section of Molecular and Cellular Biology, University of California, Davis, California 95616, USA.
The Journal of Biological Chemistry
|June 17, 2003
Summary
Actin-interacting protein 1 (Aip1p), a WD repeat protein, was structurally analyzed. Its unique "clamshell" shape and conserved residues suggest a binding site for actin and cofilin, impacting filament dynamics.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biology
Background:
- Actin-interacting protein 1 (Aip1p) is a conserved protein regulating actin filament depolymerization with cofilin.
- Aip1p possesses a WD repeat structure, with sequence data previously suggesting a maximum of 10 repeats.
Purpose of the Study:
- To determine the crystal structure of Saccharomyces cerevisiae Aip1p.
- To elucidate the structural basis for Aip1p's function in actin dynamics.
Main Methods:
- X-ray crystallography was used to determine the 3D structure of Aip1p.
- Sequence conservation analysis was mapped onto the determined structure.
Main Results:
- The crystal structure revealed Aip1p comprises two connected seven-bladed beta-propellers, forming an unexpected "clamshell" shape.
- Conserved residues cluster on one propeller surface and the inter-propeller interface, indicating potential F-actin and actin-cofilin binding sites.
- The interface between the beta-propellers appears rigid, potentially limiting large conformational changes.
Conclusions:
- The Aip1p structure provides insights into WD repeat protein architecture and actin-binding mechanisms.
- The identified conserved regions suggest a model for how Aip1p interacts with F-actin and the actin-cofilin complex.
- Structural rigidity may influence Aip1p's regulatory role in actin filament dynamics.