During her PhD studies, Marlene investigated the activation and inhibition of the p90 ribosomal S6 kinases. These kinases are known to be activated in disease mechanisms underlying psoriasis, multiple sclerosis and cancers. Further Marlene studied the sodium potassium pump, a protein that maintains large electrochemical gradients of sodium and potassium across the plasma cell membrane. These gradients are essential for the communication and transport in and out of the cell of nutrients and ions. By using X-ray crystallography, an important conformational state of the pump during its functional transport cycle, known as the E2P state, was determined. Additionally, Marlene determined the first cryo-electron microscopy structure of a neurological disease mutant of the sodium potassium pump.             

The new research findings contribute to the understanding of how these proteins function, and the studies provide a foundation for further investigations into the mechanisms of these proteins.

The PhD study was completed at the Department of Molecular Biology and Genetics, Faculty of Natural Sciences, Aarhus University. This summary was prepared by the PhD student.

Time: Friday, 18 March 2022 at 13:00
Place: Building 1252, room 204, Lecture Theatre Eduard Biermann, Aarhus University, Bartholins Allé 3, 8000 Aarhus C
Title of PhD thesis: Elucidating functional properties of the p90 ribosomal S6 kinases and the Na⁺,K⁺-ATPase: 1) Investigation of the activation and inhibition of the C-terminal kinase domain of the p90 ribosomal S6 kinases, 2) Functional and structural characterization of the beryllium fluoride inhibited Na⁺,K⁺-ATPase, 3) Towards cryo-electron microscopy studies of Alternating Hemiplegia of Childhood diseases mutants of the Na⁺,K⁺-ATPase.

Contact information: Marlene Uglebjerg Fruergaard, e-mail: marlenef@mbg.au.dk, tel.: +45 60833536

Members of the assessment committee:

• Director of Structural Biology and Protein Biochemistry Katharina Dürr, OMass Therapeutics, United Kingdom
• Professor Jens Preben Morth, Department of Biotechnology and Biomedicine, Technical University of Denmark, Denmark
• Chair: Associate Professor Knud Larsen, Department of Molecular Biology and Genetics, Aarhus University, Denmark

Main supervisor:
Professor Poul Nissen, Department of Molecular Biology and Genetics, Aarhus University, Denmark 

Co-supervisor:
Clinical Professor and Chair Lars Iversen, Department of Clinical Medicine – The Department of Dermatology and Venereology, Aarhus University, Denmark

Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS,

Katrinebjergvej 89F, building 5132, 8200 Aarhus N.