Simultaneous monitoring of surfaces and protein distribution in cells

May 28, 2018, Ruhr-Universitaet-Bochum
In order to facilitate analysis in living cells, the team is planning to develop a combined instrument in the next step. Credit: © RUB, Kramer

In a first proof-of-concept study, researchers at Ruhr-Universität Bochum (RUB) have combined two microscopy methods that render both a cell's surface and the distribution of a protein in the cell visible, at a resolution in the nanometre range. The method can be used for living cells. It might for example help analyse how cancer metastases are formed or assess the efficacy of specific drugs. The researchers from the nanoscopy workgroup at Rubion, the Central Unit for Ionbeams and Radionuclides at RUB, reported their findings in the renowned journal ACS Nano on May 23, 2018.

A first step

Significantly smaller than 250 nanometres, complexes cannot be depicted in detail using light-microscopy techniques. In order to find a way in, the RUB workgroup combined stimulated emission depletion microscopy (STED) with scanning ion conductance microscopy (SICM).

"STED microscopy enables us to analyse the distribution of proteins in . SICM facilitates high-resolution probing of the . Accordingly, we have been able to link the distribution of the cellular protein actin with the nanostructure of the cell ," explains Philipp Hagemann, Ph.D. researcher in the workgroup. "Our results constitute a first step towards high-res analysis of the surface structure, i.e. the biochemical organisation of the cell and its surrounding membrane," elaborates Dr. Patrick Happel, head of the nanoscopy workgroup.

Understanding the role of the cell membrane

The cell membrane is a fatty layer that encloses each cell, thus separating it from its surroundings. In order to communicate with their environment, have a number of different proteins that are embedded in the cell membrane and convey external stimuli into the interior of the cell. "The way proteins are organised in the cell membrane, the way their position changes, and the way those changes are orchestrated has not yet been fully understood," says Happel. The proteins in the cell membrane as well as the cell membrane itself are significant factors in this process, as cells alter their position during wound healing, during development, and also while cancer metastases are formed. Researchers refer to this process as migration.

Even though cell migration differs between different cell types, one common aspect is an expansion of the cell membrane into the direction of movement. Within the organism, migrating cells have to move through extremely narrow gaps between other cells. This is only possible if the cell is considerably deformed, and if adhesion complexes are formed at the front edge of the cell and are detached at the trailing edge. The interplay of these biochemical and biophysical processes has as yet been barely understood on the molecular level, as no method exists capable of monitoring this dynamic process in high resolution over an extended period of time.

Two-part device planned

"We have recorded the data successively with different devices. Thus, we were able to demonstrate that our method makes novel analyses possible," explains Astrid Gesper, Ph.D. researcher in the workgroup.

In order to facilitate analysis in living cells, the team is planning to develop a combined instrument in the next step. "The combination of both methods will render the transport processes visible in detail – which also plays a crucial role for targeted application of drugs via nanoparticles," concludes Patrick Happel.

Explore further: The stiffness of cell plasma membranes affects nanomedicine uptake

More information: Philipp Hagemann et al. Correlative Stimulated Emission Depletion and Scanning Ion Conductance Microscopy, ACS Nano (2018). DOI: 10.1021/acsnano.8b01731

Related Stories

Islands in yeast membrane revealed by extreme microscopy

February 5, 2018

University of Groningen microbiologists have visualized tiny islands in the cell membrane of baker's yeast. These membrane compartments appear to store transport proteins before use. The scientists observed that these proteins ...

Flipping lipids for cell transport-tubules

March 29, 2018

Researchers are getting closer to understanding the molecular processes that cause parts of cell membranes to morph into tiny tubes that can transport molecules in and out of cells.

Ras protein's role in spreading cancer

February 18, 2018

Protein systems, such as Ras, make up the complex signaling pathways that control whether a cell divides or, in some cases, becomes cancerous and metastasizes into other regions of the body. For example, 98 percent of pancreatic ...

Recommended for you

Engineers produce smallest 3-D transistor yet

December 10, 2018

Researchers from MIT and the University of Colorado have fabricated a 3-D transistor that's less than half the size of today's smallest commercial models. To do so, they developed a novel microfabrication technique that modifies ...

New traffic rules in 'Graphene City'

December 6, 2018

In the drive to find new ways to extend electronics beyond the use of silicon, physicists are experimenting with other properties of electrons, beyond charge. In work published today (Dec 7) in the journal Science, a team ...

Artificial synapses made from nanowires

December 6, 2018

Scientists from Jülich together with colleagues from Aachen and Turin have produced a memristive element made from nanowires that functions in much the same way as a biological nerve cell. The component is able to save and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.