Introducing ZMB People - Katharina Severin

Katharina Severin

PhD student, Group Michael Ehrmann, Department of Microbiology II

Interview with Katharina on July 20th, 2018

What brings you here?

Actually, I was born in Essen and I also grew up here. Then I started studying medical biology here because I really liked the curriculum. I thought that it was great because I was interested in medicine, but I also wanted to do science and to be a researcher. For my master’s thesis I went abroad for one year and I worked in the lab of Tom Rapoport at Harvard Medical School. After that, I decided to come back to Michael Ehrmann’s lab, where I had previously done my bachelor’s thesis, and that’s how I ended up here for my PhD.

What are you currently working on?

Our group works on HTRAs. HTRAs are key players in protein quality control. They can act as chaperones, helping other proteins that are not folded correctly to be folded again, or they can act as a protease. That means they can digest other proteins. I work on HTRA1, which is a human protein.

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HTRA1 is important in several severe human diseases, for example in Alzheimer’s disease, in cancer, in an eye disease called age-related macular degeneration and also in arthritis. We hope that we can help to treat these diseases by modulating HTRA1 activity.

My goal is to examine the molecular role of HTRA1 in more detail. To that end I have identified interaction partners of HTRA1. These interaction partners can either be substrates of HTRA1 which means they can be proteolyzed by HTRA1 or they can interact in some other way and have a different function. And now I examine these interactions in more detail.

What is the practical importance of your work to society?

I think that we can uncover new mechanisms of regulation through the work on HTRA1 and proteolysis, but for society just as important is the relevance in disease. HTRA1 plays a very important role in several diseases, such as Alzheimer’s disease, cancer, age-related macular degeneration and arthritis. We envision that by understanding the exact molecular mechanisms in detail, we can probably help to cure some of these diseases and for other diseases find treatments that work much better than any medicine available today.

Portrait of Katharina Severin
Portrait of Katharina Severin Portrait of Katharina Severin

What special skills are needed for your work?

I find whenever part of a project is completed successfully, there are about a hundred new questions. And it’s really important to think long and hard which questions you want to answer because there is so much that can be done but only so many hours in the day. So, I find this is one of the key aspects. Since you cannot know the outcome of an experiment, you also cannot plan everything in advance. But you can and have to make smart choices about these trials.

What was a moment of success during your research?

One of my biggest challenges was to identify interaction partners of HTRA1, which in theory is basic research and should be a thing that is not too hard to accomplish. But it turned out that for this particular protein it was challenging and so I spent quite a lot of time cloning constructs with different tags, producing my own antibody in rabbits that I had to purify and did so many different things...
Then finally, I managed to identify interaction partners and not just one but quite many. I could verify that many of these interactions are most likely real. And that was really cool, because after that I could basically pick from many proteins and decide what I wanted to work on next.

And is there something that didn’t work – that drove you nuts?

I’m wrapping up my PhD project and still have some biochemical experiments to do. I work with many different proteins and mutations. Many of these protein stocks are almost depleted, so whenever I thaw one of these proteins I really have to think carefully which experiments I want to do and then do as much as possible at once before the protein cannot be used anymore.

What do you enjoy about doing science?

I find it really exciting to try to find out what is going on in cells on a molecular level and to understand what some of the key players are doing exactly. But most importantly for me, science is a little bit like detective work. You do your experiments and after doing the experimental design, it is very manual work – you pipet and do things here and there. But when you’re done you have this result and it either makes a lot of sense or you are totally surprised, and then you have to find out what’s going on. You talk to people and you dig in the research and you have to be smart and creative and I find that super exciting and fulfilling.

What do you value here at the ZMB?

I really like that there are a lot of other researchers: young researchers, professors, students and postdocs. Everyone is really helpful. In my project I often had the situation where I had to do something that nobody in my group was really experienced in. I always found someone else who was willing to help – who had a lot of expertise and was more than willing to share their knowledge. I really like that, because there is always someone you can talk to and often you can exchange reagents and knowledge and that is a really great surrounding to do science.

Does science influence your everyday life?

Well, my husband always jokes about this, because when we cook and especially when we prepared food for our baby, he said that I did it very scientifically. Because I liked to sterilize things and then I used a scale to add the proper amount of everything.

How do you balance science and life?

I find that most of the time it works quite well because in science I often can be my own boss when it comes to working hours. I can do my experiments very early in the morning or even at night when I have to. And that is very convenient because I have two young children. This flexibility helps a lot. Sometimes it can also be difficult because some experiments just take time and you have to spend a lot of hours in the lab and that can be a challenge at times. But I have a lot of nice colleagues and it's common to help each other out when needed. So sometimes if something really goes wrong… I had this situation where I was purifying a protein and some things just cannot be planned with this. So then I was not done in time and I could not find anybody else to pick up my son from kindergarten – so one of my colleagues offered to finish the work for me. It was not a lot, but it was invaluable for me.

What do you do in your leisure time?

Since I have two children, I enjoy as much family time as I can when I’m not working in the lab or doing science. I enjoy spending a lot of time outside and I’m an absolute coffee junky – now more than ever. I like to do yoga and Pilates and I also love to read whenever I can. These are my favorite acts of self-care during this very full season of my life.

Interview, photos and video by Carola Schubert and Christian Denkhaus.
Copyright for all images and video: ZMB.

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