Molecular mechanisms governing integrin-mediated force transmission in living cells
Abstract/Contents
- Abstract
- Living cells are exquisitely tuned to the mechanical properties of their surroundings. Indeed, physical forces such as substrate rigidity, fluid shear, and stretch guide cellular processes such as stem cell differentiation, wound healing, and development. Additionally, disruption in the ability of cells to sense the mechanical properties of their surroundings represents a hallmark of many diseases, including muscular dystrophy, arteriosclerosis, cardiomyopathies, and cancer. Although cells have numerous mechanisms for detecting mechanical inputs, one of the most prominent is through integrins, heterodimeric transmembrane proteins that cluster into micrometer-sized assemblies termed focal adhesions (FAs). FAs link the extracellular matrix (ECM) to the cell cytoskeleton and are composed of hundreds of different proteins, many of which are proposed to sense force. How the many proteins within FAs are organized into force sensing and transmitting structures is poorly understood. Additionally, the mechanisms describing how FAs regulate force transduction is not well established, due primarily to a lack of tools to visualize cell-generated forces at molecular resolution. Here, we describe Förster resonance energy transfer (FRET)-based molecular tension sensors that allow us to directly visualize cell-generated forces with single-molecule sensitivity. We apply these sensors to measure forces transmitted by integrins in living cells and find that relatively modest tensions at the molecular level are sufficient to drive robust cellular adhesion. We observe strikingly complex distributions of tension within individual FAs, and characterize the organization of various adhesion components with respect to tension generation. We combine fluorescent molecular tension sensors with super-resolution light microscopy to visualize traction forces within FAs at < 100 nm spatial resolution. Finally, using these sensors we establish that metastatic cancer cells generate modest increases in integrin-mediated forces and we use proteomics to identify potential molecular associations that contribute to this increase in tension and thus the progression of cancer.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Mekhdjian, Armen Haig |
|---|---|
| Associated with | Stanford University, Department of Chemical Engineering. |
| Primary advisor | Dunn, Alexander Robert |
| Thesis advisor | Dunn, Alexander Robert |
| Thesis advisor | Khosla, Chaitan, 1964- |
| Thesis advisor | Nelson, William |
| Advisor | Khosla, Chaitan, 1964- |
| Advisor | Nelson, William |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Armen Haig Mekhdjian. |
|---|---|
| Note | Submitted to the Department of Chemical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Armen Mekhdjian
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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