Membrane Remodeling of Giant Vesicles in Response to Localized Calcium Ion Gradients
Journal article, 2018

In a wide variety of fundamental cell processes, such as membrane trafficking and apoptosis, cell membrane shape transitions occur concurrently with local variations in calcium ion concentration. The main molecular components involved in these processes have been identified; however, the specific interplay between calcium ion gradients and the lipids within the cell membrane is far less known, mainly due to the complex nature of biological cells and the difficultly of observation schemes. To bridge this gap, a synthetic approach is successfully implemented to reveal the localized effect of calcium ions on cell membrane mimics. Establishing a mimic to resemble the conditions within a cell is a severalfold problem. First, an adequate biomimetic model with appropriate dimensions and membrane composition is required to capture the physical properties of cells. Second, a micromanipulation setup is needed to deliver a small amount of calcium ions to a particular membrane location. Finally, an observation scheme is required to detect and record the response of the lipid membrane to the external stimulation. This article offers a detailed biomimetic approach for studying the calcium ion-membrane interaction, where a lipid vesicle system, consisting of a giant unilamellar vesicle (GUV) connected to a multilamellar vesicle (MLV), is exposed to a localized calcium gradient formed using a microinjection system. The dynamics of the ionic influence on the membrane were observed using fluorescence microscopy and recorded at video frame rates. As a result of the membrane stimulation, highly curved membrane tubular protrusions (MTPs) formed inside the GUV, oriented away from the membrane. The described approach induces the remodeling of the lipid membrane and MTP production in an entirely contactless and controlled manner. This approach introduces a means to address the details of calcium ion-membrane interactions, providing new avenues to study the mechanisms of cell membrane reshaping.

microinjection

Issue 137

Giant vesicles

calcium ions

calcium gradient

membrane tubular protrusions

Chemistry

spontaneous curvature

lipid membrane

membrane remodeling

micromanipulation

Author

Baharan Ali Doosti

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry, Physical Chemistry

Ann-Sofie Cans

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Gavin Jeffries

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry, Physical Chemistry

Tatsiana Lobovkina

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Journal of Visualized Experiments

1940-087X (ISSN)

137 e57789

Subject Categories

Cell Biology

Cell and Molecular Biology

Biophysics

PubMed

30059020

More information

Latest update

3/19/2019