Abstract
Molecular optogenetic switch systems are extensively employed as a powerful tool to spatially and temporally modulate a variety of signal transduction processes in cells. However, the applications of such systems in mechanotransduction processes where the mechanosensing proteins are subject to mechanical forces of several piconewtons are poorly explored. In order to apply molecular optogenetic switch systems to mechanobiological studies, it is crucial to understand their mechanical stabilities which have yet to be quantified. In this work, we quantify a frequently used molecular optogenetic switch, iLID-nano, which is an improved light-induced dimerization between LOV2-SsrA and SspB. Our results show that the iLID-nano system can withstand forces up to 10 pN for seconds to tens of seconds that decrease as the force increases. The mechanical stability of the system suggests that it can be employed to modulate mechanotransduction processes that involve similar force ranges. We demonstrate the use of this system to control talin-mediated cell spreading and migration. Together, we establish the physical basis for utilizing the iLID-nano system in the direct control of intramolecular force transmission in cells during mechanotransduction processes.
- Received 10 July 2019
- Revised 9 January 2020
- Accepted 26 February 2020
DOI:https://doi.org/10.1103/PhysRevX.10.021001
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
To sense mechanical stimuli and translate them into biochemical reactions, cells rely on a process known as mechanotransduction, mediated by force-transmitting linkages within the cell built from a few linked proteins. Previous investigations of the mechanisms underlying mechanotransduction have mainly focused on individual proteins that constitute the linkages. However, the roles of the linkages have remained largely unexplored. To address this lack of understanding, it is necessary to spatially and temporally control the physical connectivity of these force-transmission linkages and observe the resulting responses of cells. We show that it is possible to do this using a common light-based technique for connecting proteins known as light-induced dimerization.
The key is to identify a mechanically stable complex formed by a pair of light-dependent interacting protein domains. Inserted into a force-transmission linkage, the pair of domains enable the direct control of the linkage connectivity by light. Using single-molecule manipulation and single-cell imaging approaches, we quantify the mechanical stability of a popular light-induced dimerization system and show that it confers enough mechanical stability to connect an important force-transmission linkage from the extracellular matrix to the cytoskeleton network, which in turn activates the migration of single cells by light.
These approaches can be used to develop a toolbox of mechanically stable light-induced dimerization systems to reveal the mechanisms of specific force-transmission linkage-dependent mechanotransduction. In addition, the toolbox can also be used to develop light-sensitive functional materials.