# Label-Free Super-Resolution Imaging of Membrane Proteins

> **NIH NIH R35** · UNIVERSITY OF MINNESOTA · 2020 · $277,730

## Abstract

Probing nanoscale membrane dynamics with label-free super-resolution microscopy
 Renee R. Frontiera, Department of Chemistry, University of Minnesota
 The objective of this research is to determine how the membrane environment around a
given membrane protein affects its function. Membrane proteins are critical for cellular
signaling and transport, and are the targets of a large number of currently-marketed
pharmaceuticals. These proteins exist in a dynamic and heterogeneous membrane environment,
with highly variable chemical composition, thickness, and fluidity. These membrane parameters
are thought to have significant impact of protein function, but direct causative correlations
between the molecular-level membrane environment and the effectiveness of processes like
drug binding and signal transduction are largely unknown. This is primarily due to the
challenges of studying these small proteins in their natural environment, as they have sizes on
the 1-100 nm length scale, well below the traditional optical diffraction limit.
 The proposed research will utilize an original label-free super-resolution microscopy
technique to investigate how the local environment around a membrane protein affects its
function. The chemical composition of a living cellular membrane will be mapped without the
need for exogenous labels by using a new technique which couples ideas from the Stimulated
Emission Depletion (STED) microscopy and Femtosecond Stimulated Raman Spectroscopy
(FSRS) techniques. The use of a label-free, super-resolution imaging technique with the ability
to follow ultrafast reaction dynamics represents a fundamentally new and innovative approach
to studying reactions in biological systems.
 The proposed investigations are designed to demonstrate the broad role of membrane
protein environments on membrane protein function through an examination of several
systems. In particular, investigations will focus on (i) agonist binding rates and efficiencies to G-
protein coupled receptors; (ii) endocytosis of siRNA in various drug delivery vehicles; and (iii)
ion channel activation and transport efficiency. The work will have significant impact on human
health by providing a molecular-level picture of how dynamics heterogeneous local
environments affect the function of membrane proteins, particularly during drug binding and
signaling events. The results of the proposed studies will lead to a better understanding of how
currently marketed pharmaceuticals function, and determine which specific molecular-scale
factors are responsible for a wide range of responses and efficacies.

## Key facts

- **NIH application ID:** 9952381
- **Project number:** 5R35GM119441-05
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **Principal Investigator:** Renee R Frontiera
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $277,730
- **Award type:** 5
- **Project period:** 2016-08-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9952381

## Citation

> US National Institutes of Health, RePORTER application 9952381, Label-Free Super-Resolution Imaging of Membrane Proteins (5R35GM119441-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9952381. Licensed CC0.

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