# Repurposing Bacterial Mechanosensitive Channel as a Membrane Tension Biosensor

> **NIH NIH R21** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $296,797

## Abstract

Defects in mechanotransduction – the cellular processes that convert mechanical stimuli into biochemical
signals – are implicated in the development of a wide range of diseases, including cardiomyopathies,
muscular dystrophies, and cancer progression. Tension of the plasma membrane has been increasingly
recognized to actively regulate many cellular processes, including cell migration and membrane trafficking.
The conventional view that the plasma membrane is a two-dimensional fluid lipid bilayer with embedded
proteins has led to the idea that membrane tension could transmit forces over long-range to regulate cell
polarity and migration. However, recent work has pointed to local variation of membrane tension can
mediate distinct sub-cellular processes. While there exist approaches to measure membrane tension, the
techniques require specialized setup and expertise. This has severely limited research progress in key
questions in cell mechanotransduction. To address this unmet need, the objective of the proposed work is
to repurpose bacterial mechanosensitive channel MscL as a membrane tension biosensor. The large
conformational changes predicted from structural and biophysical studies coupled with phenomenal
successes in recent years on protein-based biosensors make MscL an ideal candidate for engineering a
membrane tension sensor. Recent work in our lab has demonstrated functional reconstitution of MscL in
mammalian cells. Further, we have accrued a range of innovative methodologies for reconstituting MscL in
vitro and for manipulating and measuring cell mechanics properties. In Aim 1, we will insert circular
permutated GFP (cpGFP) in the periplasmic loop of MscL and systematically engineer it for increased
responsiveness and sensitivity. We will characterize cpGFP-MscL reconstituted into lipid bilayer vesicles
and select the most optimal sensor experiments in living cells. In Aim 2, we will establish the connection
between membrane tension and cell contractility, as this important relationship between the two has never
been determined but assumed. We will measure membrane tension in cells with different spreading areas
and also evaluate dynamic changes of membrane tension in cells subjected to hypo-osmotic shock. These
experiments will resolve the spatiotemporal dynamics of membrane tension in cellular process known to
have membrane tension changes. The high spatial and temporal resolution afforded by the fluorescence-
based membrane tension biosensor is expected to have transformative impact in membrane biophysics,
developmental biology (where dramatic morphological dynamics that takes place is expected to elevate
membrane tension), and mechanobiology.

## Key facts

- **NIH application ID:** 9986844
- **Project number:** 5R21GM134157-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Allen Po-Chih Liu
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $296,797
- **Award type:** 5
- **Project period:** 2019-08-01 → 2021-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9986844

## Citation

> US National Institutes of Health, RePORTER application 9986844, Repurposing Bacterial Mechanosensitive Channel as a Membrane Tension Biosensor (5R21GM134157-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9986844. Licensed CC0.

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