Probing force-dependent interactions between aE-catenin, vinculin and F-actin
Abstract/Contents
- Abstract
- Classical cadherins are transmembrane proteins whose extracellular domains link neighboring cells, and whose intracellular domains connect to the actin cytoskeleton via β-catenin and α-catenin. The cadherin-catenin complex transmits forces that drive tissue morphogenesis and wound healing. αE-catenin binds directly to filamentous actin (F-actin) and displays catch bond behavior, such that force applied to the cadherin-catenin complex increases its lifetime on actin. Tension-dependent changes in αE-catenin conformation enable it to recruit the actin-binding protein vinculin to cell-cell junctions, where it contributes to junctional strengthening. Vinculin also plays a similar role at cell-matrix adhesions, where it is recruited to talin in a tension-dependent manner. I used single-molecule optical trap assays to probe the force-dependence of vinculin's interaction with F-actin. I found that vinculin's interaction with F-actin displays directional catch bond behavior -- that is, force directed towards the pointed (-) end of the F-actin results in mean binding lifetimes 3-fold longer than when load was applied towards the barbed (+) end. In a second set of experiments, I sought to assess whether vinculin might regulate the binding interaction between αE-catenin and F-actin. To do this, I measured force-dependent actin binding by a quaternary complex comprising the cadherin-catenin complex and the vinculin head region, which cannot itself bind actin. Binding lifetimes of this quaternary complex increased as additional complexes bound F-actin, but only when load was oriented toward the (-) end of the filament. In contrast, the cadherin-catenin complex alone did not show this form of cooperativity. Together, my findings reveal molecular mechanisms which may facilitate the higher-order cytoskeletal organization necessary for cellular functions such as cell-cell adhesion and cell mobility.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Bax, Nicolas A |
|---|---|
| Degree supervisor | Dunn, Alexander Robert |
| Degree supervisor | Weis, William I |
| Thesis advisor | Dunn, Alexander Robert |
| Thesis advisor | Weis, William I |
| Thesis advisor | Brünger, Axel T |
| Thesis advisor | Bryant, Zev David |
| Degree committee member | Brünger, Axel T |
| Degree committee member | Bryant, Zev David |
| Associated with | Stanford University, Department of Structural Biology |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Nicolas A Bax. |
|---|---|
| Note | Submitted to the Department of Structural Biology. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/yd574ws4040 |
Access conditions
- Copyright
- © 2021 by Nicolas A Bax
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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