CHIMs are versatile cholesterol analogs mimicking and visualizing cholesterol behavior in lipid bilayers and cells

Anna L L Matos,Fabian Keller,Andreas Heuer,Frank Glorius,Sergej Kudruk,Anne Spang,David Grill,Tristan Wegner,Carla Elizabeth Cadena Del Castillo,Volker Gerke

doi:10.1038/s42003-021-02252-5

Anna L L Matos, Fabian Keller + Show 8 more

Open Access

https://doi.org/10.1038/s42003-021-02252-5

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Abstract

Cholesterol is an essential component of cellular membranes regulating the structural integrity and fluidity of biological bilayers and cellular processes such as signal transduction and membrane trafficking. However, tools to investigate the role and dynamics of cholesterol in live cells are still scarce and often show limited applicability. To address this, we previously developed a class of imidazolium-based cholesterol analogs, CHIMs. Here we confirm that CHIM membrane integration characteristics largely mimic those of cholesterol. Computational studies in simulated phospholipid bilayers and biophysical analyses of model membranes reveal that in biologically relevant systems CHIMs behave similarly to natural cholesterol. Importantly, the analogs can functionally replace cholesterol in membranes, can be readily labeled by click chemistry and follow trafficking pathways of cholesterol in live cells. Thus, CHIMs represent chemically versatile cholesterol analogs that can serve as a flexible toolbox to study cholesterol behavior and function in live cells and organisms.

Highlights

Cholesterol is an essential component of cellular membranes regulating the structural integrity and fluidity of biological bilayers and cellular processes such as signal transduction and membrane trafficking
In the molecular dynamics (MD) simulations we focused on a comparison between cholesterol and CHIM to characterize the effect of changing the hydroxyl group to an imidazolium salt residue
The amount of 30 mol% sterol was chosen to have a strong impact of these moieties on bilayer properties and because it resembles the amount of CHOL found in natural plasma membranes (PMs)[16,17]

Summary

Introduction

Cholesterol is an essential component of cellular membranes regulating the structural integrity and fluidity of biological bilayers and cellular processes such as signal transduction and membrane trafficking. 1234567890():,; Biological membranes are composed of different types of lipids, phospholipids, sphingolipids and cholesterol, and integral as well as associated proteins They can adopt a vast array of configurations and are highly dynamic in nature, allowing rapid lateral diffusion and assembly and disassembly of their principal components. Due to its unique design CHIM addresses many drawbacks of established cholesterol analogs; it should enable the visualization of cholesterol distribution in live cells without the need for cell fixation and should allow a flexible on-demand attachment of any fluorophore of choice or other functional groups (e.g. photoswitches, crosslinkers, or biotin labels) that could be used for the investigation and manipulation of the native cholesterol membrane environment. We envision that this highly modifiable class of cholesterol analogs will serve as important tools and flexible platforms for the investigation of cholesterol-dependent membrane processes

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