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Actin Co-Sedimentation Assay; for the Analysis of Protein Binding to F-Actin
Published on: March 28, 2008
Structural studies on full-length talin1 reveal a compact auto-inhibited dimer: implications for talin activation
Benjamin T Goult1, Xiao-Ping Xu, Alexandre R Gingras
1Department of Biochemistry, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK.
Journal of Structural Biology
|June 4, 2013
Summary
Talin, a protein crucial for cell adhesion, forms a compact, donut-shaped dimer. This structure masks its binding sites, indicating it must unfold to activate integrins and connect to the cytoskeleton.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Talin is a large adaptor protein essential for integrin activation and linkage to the actin cytoskeleton.
- It comprises an N-terminal FERM domain (head) and a C-terminal rod domain (R1-R13) ending in a dimerizable helix (DD).
Purpose of the Study:
- To determine the three-dimensional structural model of full-length talin.
- To understand the conformation of talin in its resting state and its implications for protein function.
Main Methods:
- Electron microscopy (EM) reconstruction of full-length talin.
- Integration of small-angle X-ray scattering (SAXS) data for domain shapes and angles.
Main Results:
- A 3D structural model of full-length talin was generated at ~2.5nm resolution.
- Talin adopts a compact, donut-shaped dimeric conformation.
- The talin heads (FERM domains) are located in the center of the donut, and the actin-binding sites are masked.
Conclusions:
- The compact talin dimer structure explains how integrin and actin binding sites are sequestered in an inactive state.
- Talin must undergo significant conformational changes (unraveling) to become active and mediate cell adhesion.
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