Prof.Dr. Mireille Claessens

trying to unravel unstructured protein

From an early age, Mireille Claessens has had a broad interest and great curiosity. “I'm always looking for how things work,” she says. When she became a student in Wageningen, this question specified to ‘how life works’. Since her PhD research on drought tolerance in plants, her attention has shifted from entire cells to proteins, which perform most of the tasks in the cell.

More specifically, Claessens investigates intrinsically disordered proteins. “The vast majority of proteins are folded in some way and their shape is linked to their function in the cell,” she says. “However, some proteins do not fold into a certain structure and are still functional. Alpha-synuclein, the protein that clumps together in Parkinson's brain disease, is one such unstructured protein that we don’t understand very well yet. In our research we are trying to unravel the normal function of alpha-synuclein in the cell and to discover what makes these proteins clump together and cause problems in a condition such as Parkinson's disease.”

The Nanobiophysics group led by Claessens leads has an excellent infrastructure for their research, because they can ‘look at’ the proteins individually as well as in bulk. “That combination is quite unique,” says the professor. “We combine fluorescence microscopy with bulk spectroscopy to make predictions and investigate the protein’s behavior under different conditions.” Claessens and her colleagues now suspect that intrinsically unfolded or unstructured proteins, such as alpha-synuclein, fulfill a kind of network function in the cell. “These proteins are very adaptable for interactions with each other and with other proteins. This also makes them clump together easily when the cell is disturbed due to illness, old age or an external cause (like a virus infection). We are trying to discover what goes wrong, exactly where in the protein it goes wrong, and what the causes could be.”

Prof. Dr. Mireille Claessens

We are trying to understand the role and function of unstructured proteins, so that we may one day be able to intervene with medication when these proteins cause problems, like in Parkinson's disease

Prof. Dr. Mireille Claessens

The techniques Claessens uses for protein research, are also relevant for other research areas, like the detection of nanoplastics for example. “To investigate the effect of nanoplastics on ecosystems or organisms, we first need to be able to find them, which is already very complicated with (larger) microplastics,” Claessens says. “With our equipment it is possible to determine the concentration of even smaller (nano)plastic particles. Although this field of research is only just emerging, I think it is important to get further into this, because it is a big problem and we should not burden future generations with.” 


Although she has many organizational tasks as a professor, Claessens tries to be involved as much as possible with the PhD students and postdocs in her group. “I still really enjoy lab work and don't want to be only involved indirectly. I also like to occasionally elaborate some data myself,” she says.

Claessens also teaches various courses in the field of physical biology and biochemistry within the Applied Physics and Chemical Science & Engineering educational programs. She sees an important role for research groups in the education: “We constantly have students in our lab working on their bachelor's or master's research assignment. They are taking their first steps towards independent research and I think it is important to contribute to this. Although I do not supervise the students on a day-to-day basis, I do try to play a modest role in their development.”

About Mireille Claessens

Mireille Claessens is professor of Nanobiophysics at the Faculty of Applied Sciences of the University of Twente. Claessens studied Molecular Sciences at the University of Wageningen and also obtained her PhD there. After a postdoc period in Munich, she became a university lecturer in 2007 at the University of Twente, where she started her research into protein clumping in diseases such as Parkinson's. In 2009 she received a Vidi grant from NWO to start her own research group and in 2018 she became one of the four Westerdijk professors at the University of Twente. Her group investigates intrinsically unfolded proteins using the latest microscopy and spectroscopy techniques, which they can also use for other issues at the interface of nanotechnology and biology, such as the detection of viruses or nanoplastics.

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