"Suddenly, infectious disease researchers got interested in our work"

Interview with new Max Planck Fellow Simone Reber

April 25, 2023

On the first of January, Simone Reber started her Max Planck Fellowship at the Max Planck Institute for Infection Biology. With her research group "Quantitative Biology", she investigates how cell organelles are organized and which biochemical and physical principles lie behind this self-organization. In the interview, Simone describes the research project that opened up the world of infection biology to her and explains the meaning of the group name "Quantitative Biology".

Welcome to the Institute, Simone. How did you come to be a Max Planck Fellow—what brings you to our Institute?

I guess the right word for it would be serendipity. I'm not an infectious disease researcher in the strict sense. My group focusses on the question of how organelles regulate their material properties and geometry. A classic example of this is the mitotic spindle. When a cell divides by mitosis, its genetic material must also be divided. The mitotic spindle pulls the chromosomes apart and divides them between the two new cells. For this task, the spindle must be long and elastic, otherwise the chromosomes will be split incorrectly and for example trisomies will result.

To investigate these material properties, we took a closer look at the individual fibers of the spindle, the so-called microtubules. They are a popular target of chemotherapies, for example against cancer, because the microtubules can directly influence cell division. We wondered whether this target could not only be used against our own cells, as in chemotherapy, but also against parasites.

My research group then succeeded in purifying tubulin, the building block of microtubules, from parasites—more precisely from Plasmodium, the parasite that causes malaria. We have already purified tubulin from various organisms, so for us this was not so special. But with the paper we published on this in 2021, we suddenly had a whole new peer group. Suddenly, infectious disease researchers were also interested in our work, and that was an impetus for my application for the Max Planck Fellowship.

Because we also have a malaria focus at the Max Planck Institute for Infection Biology?

That was one of two reasons. On the one hand, our research in the area of parasite tubulin also fits in with the research questions of Silvia Portugal and Elena Levashina, who both head malaria research groups. On the other hand, there are also research groups with which we have methodological overlaps. After all, our research approach is quantitative biology and especially quantitative imaginghere at the institute Marcus Taylor and Olivia Majer are working in very similar areas. 

You've been a fellow since the first of January, what were your first steps?

We first set up our microscope. It's homemade, so there are no instructions on how to easily set it up and take it down. We had to make sure everything was back up and running and that we could reproduce our measurements.

In research, our first step is that we want to purify parasite tubulin in larger quantities. When working biochemically with malaria parasites, five to ten milliliters of blood in which the parasites are cultivated are mostly sufficient. But we want to purify the protein tubulin from the parasites, and for that we need about five liters of blood cell culture. That's quite a leap and can't be scaled up easily. Just as baking a muffin is different from making a cake ten meters in diameter. What works with ten milliliters doesn't have to work in five liters. So that's our next step here at the institute.

Your research group is called "Quantitative Biology”—what is behind this name?

The name of my group "Quantitative Biology" describes our approach to biological research. Whereas in the pastto put it simplya single microscopy image of a cell was sufficient for control, we want to make things measurable. The concern of modern cell biologists should be to quantify everything you find out in experiments. We want to measure, analyze data, generate statistics and develop models to understand how much physics is in a cell.

In one of our projects we measure how dense different areas of a cell are. To understand the processes in the cell, we also need to understand under which conditions they take placethis includes material properties such as density. It makes a big difference whether a reaction takes place in aqueous solution or in a viscous liquid. Just as it makes a difference whether you want to swim in a normal pool or one filled with honey.

So far it was not possible to determine this specific density of areas of the cell, such as the nucleus. We built our own microscope and developed our own software for this purpose and were able to show that the cell nucleus is less dense than the cell plasma surrounding it. This is a surprising finding, because until now it was assumed that the cell nucleusin which meters of DNA are tightly packedis denser than the rest of the cell. After our first measurement, we therefore assumed that this was a slip, specific to the type of cell we were studying. However, we then asked some of our biologist friends to send us their "favorite cell" and measured their nuclei as well. And even in ten different organisms, from humans to fruit flies, the nucleus was always less dense than the rest of the cell. This surprised us and many others.

Showing once again—as with tubulin—that your research is interesting for many areas of biology.

Exactly, first of all this concerns almost every cell biologist, because almost every eukaryotic cell has a cell nucleus. And many essential processes between the nucleus and the cytoplasm depend on its material properties.

You have already worked at the Max Planck Institute for Cell Biology and Genetics. How does it feel to be back at the Max Planck Society now?

I am delighted! Not being asked what color to paint my cell culture was just about everything. But all joking aside, I have been to many great research institutions and I really appreciate the support in these institutions. Most of all, I'm happy that my team also gets to enjoy the benefits of the Max Planck community.

What excites you about research?

What I enjoy most is talking and discussing research with others. I'm interested in my research, of course, but I enjoy discussing it in thesis committees just as much as you can advance the research of doctoral students. For me, research is mostly about collaborating with people who have a similar mindset, ask interesting questions, and have fun doing it.

Interview conducted by Christian Denkhaus

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