Related Experiment Video
Updated: May 15, 2026

06:17
Measuring Protein Binding to F-actin by Co-sedimentation
Published on: May 18, 2017
Dimer asymmetry defines α-catenin interactions
Erumbi S Rangarajan1, Tina Izard
1Department of Cancer Biology, Scripps Research Institute, Jupiter, Florida, USA.
Nature Structural & Molecular Biology
|January 8, 2013
Summary
Alpha-catenin, a protein crucial for cell junctions, forms an asymmetric dimer. This unique structure explains its varying interactions with F-actin and vinculin, clarifying cell adhesion mechanisms.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Alpha-catenin (α-catenin) is a cytoskeletal protein essential for stabilizing cell-cell junctions by interacting with β-catenin-cadherin complexes.
- Its interaction with F-actin is regulated, and it appears necessary for adherens junction stability through interactions with vinculin.
Purpose of the Study:
- To determine the crystal structure of human α-catenin.
- To elucidate the structural basis for α-catenin's differential binding affinities to F-actin and its role in cell adhesion.
Main Methods:
- X-ray crystallography of nearly full-length human α-catenin.
- Analysis of the resulting 3.7-Å resolution structure.
Main Results:
- The crystal structure reveals α-catenin forms an asymmetric dimer with distinct subunit conformations, resembling a 'left handshake'.
- This dimeric structure explains higher F-actin affinity compared to monomeric α-catenin.
- The structure clarifies why the β-catenin-α-catenin complex doesn't bind F-actin and how vinculin links to the cytoskeleton.
Conclusions:
- The asymmetric dimeric structure of α-catenin is key to its function in cell-cell junction stability.
- Understanding this structure provides insights into the regulation of cell adhesion and the cytoskeleton.
Related Concept Videos
Catenins
Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
Tension Response at Adherens Junctions
The adherens junctions that anchor cells together are multi-protein complexes that dynamically adapt to mechanical stimuli such as tensile forces and shear stress. Mechanosensory proteins in these junctions can sense such mechanical stimuli and undergo a shift in their conformation, resulting in an altered function — a process called mechanotransduction.
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
Polarity of the Cytoskeleton
The intrinsic polarity of cells can be primarily attributed to two factors- i) the asymmetric accumulation of mobile components such are regulatory molecules and subcellular components across the cell and ii) the orientation of polar cytoskeletal filaments that make up the cytoskeletal networks, specifically microfilaments, and microtubules arranged along the axis of polarity. Interactions between the cytoskeletal filaments are crucial for the establishment and maintenance of the polar nature...
Cadherins in Tissue Organization
The cadherins are a superfamily of cell adhesion molecules comprising over 180 variants, with specific tissues expressing a particular combination of cadherin types. Cadherins generally exhibit homophilic binding; i.e., cadherins on one cell bind to cadherins of the same or closely related type on another cell. Thus, cells of the same type have a specific affinity to bind to each other and sort themselves into clusters to form tissues.
Cell Sorting During Development
Cell sorting plays an...
Cell Sorting During Development
Cell sorting plays an...
Cytoskeletal Coordination in Cell Migration
A migrating cell changes its shape during the cyclic events of attachment and detachment from the substratum and repositions the cell organelles correspondingly. These complex events are orchestrated by the dynamic cytoskeletal network comprising actin filaments, intermediate filaments, and microtubules. Cytoskeletal crosstalk — the direct and indirect communication between the different components — is crucial for this coordination. Direct communication involves various linker proteins that...
Structure of Cadherins
The cadherins were one of the first cell adhesion molecules discovered; the term “cadherins” is based on their calcium-dependent adhering properties. The first cadherins discovered on the epithelial, neuronal, and placental cells were named E-cadherin, P-cadherin, and N-cadherin, respectively. These classical cadherins share sequence and structural similarities. Other cadherins, including those involved in cell signaling, are grouped into non-classical cadherins. This diversity of cadherins...