# Deciphering Signaling and Cell Behavior with Subcellular Optogenetics

> **NIH NIH R35** · WASHINGTON UNIVERSITY · 2021 · $583,311

## Abstract

Abstract
GPCR signaling pathways regulate many cellular functions including migration. GPCR mediated cell migration
is at the basis of immune and tumor cell migration and is central to pathologies such as tumor invasiveness. A
number of signaling and cytoskeletal proteins involved in cell migration have been identified. But it is not clear
how these molecules respond to extracellular cues and operate together in a spatially dynamic network to
govern cell migration. To address this question, in the existing grants, we have focused on the development of
optogenetic strategies to control GPCR and G protein subunit signaling. In this proposal for a MIRA, we have
expanded the optogenetic strategies to newer targets: to small G proteins -- Cdc42, Rac and RhoA;
cytoskeletal proteins; and plasma membrane tension. Our recent results using these strategies show firstly,
that selective optical activation of Cdc42 and RhoA can direct the entire range of migratory responses.
Secondly, that a novel optogenetic tool that induces localized decrease in plasma membrane tension can lead
to cell migration in a direction precisely sensitive to the location of decreased tension. Based on these results,
here we propose to examine a model that an extracellular signal evokes spatially coordinated changes in
signaling activity, cytoskeletal proteins and localized plasma membrane tension that result in the migratory
response. To test this hypothesis we will address the following questions. How does the front of the cell
communicate with the back? How does a cell respond globally to localized retraction? What is the function of
the uropod? What is the role of adhesion dynamics? How does plasma membrane tension control migration?
Optogenetic strategies will be used to perturb signaling activity, cytoskeletal proteins and localized plasma
membrane tension. Sensors will be used to detect subcellular molecular and cellular responses. Magnetic
tweezers will be used to measure tension across migrating cells. The transition of immune cells such as
macrophages and tumor cells from amoeboid to mesenchymal state and back plays an important role in tumor
invasiveness. Using transcriptome analysis we will identify genes upregulated in amoeboid cells in comparison
to mesenchymal cells and target them optically, genetically and chemically to understand the basis of
amoeboid cell movement. We will examine migration in 3D matrices where cells undergo this transition in
migratory mode. We anticipate this approach to identify how dynamic interactions between signaling,
cytoskeleton and plasma membrane govern migration.

## Key facts

- **NIH application ID:** 10132745
- **Project number:** 5R35GM122577-05
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** NARASIMHAN GAUTAM
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $583,311
- **Award type:** 5
- **Project period:** 2017-04-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10132745

## Citation

> US National Institutes of Health, RePORTER application 10132745, Deciphering Signaling and Cell Behavior with Subcellular Optogenetics (5R35GM122577-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10132745. Licensed CC0.

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