Evolved and engineered molecular force sensors in the brain
Abstract/Contents
- Abstract
- Mechanical force plays an integral role in biological processes ranging from tissue development to cancer metastasis, but the ways by which forces are transduced remain largely unknown. In particular, force has emerged as a potentially important driver of processes involved in the formation and function of the nervous system and brain. In the first portion of this work, I discuss two ways in which mechanical force can regulate important physiological processes in the brain at the molecular and cellular scales. First, I describe our efforts to characterize the mechanosensitivity of latrophilins, a class of adhesion G-protein coupled receptors (aGPCRs) that are implicated in multiple neuropsychiatric diseases and control excitatory synapse formation. These molecules were hypothesized to function as mechanosensors at the synapse, but the physiological plausibility of such a hypothesis was unknown. Using magnetic tweezers, we demonstrate that forces of 1-10 pN, well within the physiological range of forces, are sufficient to accelerate the rate of a key conformational change in the latrophilin-3 receptor by 10000-fold compared to the rate in the absence of force. Thus, mechanical force may be a driver of latrophilin signaling during synapse formation, suggesting a physiological mechanism by which aGPCRs may mediate mechanically induced signal transduction. As a second example, I discuss our work exploring changes in the force generation capabilities of neural stem cells in the aging brain. ATAC-seq of activated neural stem cells (aNSCs) from mouse brains reveals that chromatin accessibility is enhanced at loci associated with cell-substrate adhesion in older brains compared to younger brains. We use FRET-based force sensors to measure forces associated with cell-ECM adhesion in aNSCs and demonstrate that these adhesive forces are heightened in aNSCs from older brains. In the second portion of this work, I describe a new class of molecular tension sensors that we have engineered to increase the accessibility of force measurements in biological systems. These tension sensors are derived from the human muscle protein titin and can be used in fixed or live cells to provide either fluorescent or bioluminescent readout of the spatiotemporal dynamics of force transmission. We use magnetic tweezers to demonstrate that our sensor responds to forces > 2 pN and apply our sensor to living systems to visualize physiological, cell-generated adhesive forces. These results illustrate the utility of our tools for measuring molecular-scale forces in biological systems, which may facilitate a better understanding of mechanical forces in the brain and in biology more broadly. Taken together, these studies highlight several mechanisms that nature has evolved for force sensing in the brain and outline ways in which force sensors can be engineered to uncover new insights about mechanotransduction.
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 | 2024; ©2024 |
| Publication date | 2024; 2024 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Zhong, Brian Lawrence |
|---|---|
| Degree supervisor | Dunn, Alexander Robert |
| Thesis advisor | Dunn, Alexander Robert |
| Thesis advisor | Khosla, Chaitan, 1964- |
| Thesis advisor | Südhof, Thomas C |
| Degree committee member | Khosla, Chaitan, 1964- |
| Degree committee member | Südhof, Thomas C |
| Associated with | Stanford University, School of Engineering |
| Associated with | Stanford University, Department of Chemical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Brian L. Zhong. |
|---|---|
| Note | Submitted to the Department of Chemical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2024. |
| Location | https://purl.stanford.edu/yb345zk2583 |
Access conditions
- Copyright
- © 2024 by Brian Lawrence Zhong
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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