Mads Schak Toustrup-Jensen

Research

My work focuses on structure-function relationships of the Na+,K+-ATPase studied by site-directed mutagenesis. In our lab we have through many years developed a variety of assays, including fast kinetic measurements at a millisecond time scale, for measuring the individual partial reaction steps in the Na+,K+-ATPase pump cycle of mutants expressed in cell culture. This allows us to detect specific functional effects of amino acid substitutions, and we have become able to distinguish direct effects of mutations on cation binding from indirect effects due to changes in conformational equilibria. Our techniques also include measurements of K+ (86Rb+) transport into intact transfected cells, and measurements of intracellular Na+ and K+ content in transfected cells. These techniques are e.g. used to examine the Pathophysiology underlying the neurological disorders familial hemiplegic migraine type 2 (FHM2) and rapid-onset dystonia parkinsonism (RDP) caused by mutations in the genes encoding the brain specific Na+,K+-ATPase isoforms a2 and a3, respectively. Another focus area is the localization and structure of the unique third Na+ binding site in the Na+,K+-ATPase, as well as the possible role of the C-terminus as a gate controlling the access to the third Na+ site.

Research interests

  • Structure-function relationships in Na+,K+-ATPase and in P-type ATPases generally.
  • Pathophysiology of the neurological disorders familial hemiplegic migraine (FHM) and rapid-onset dystonia parkinsonism (RDP).

Methodologies

  • Cloning and DNA-purification
  • Eukaryotic expression systems: COS cells
  • Isotope techniques: Using the radioactive isotopes 32P and 86Rb.
  • Enzyme kinetics: Including fast kinetic measurements at a millisecond time scale, measurements of overall ATPase activity, phosphorylation/dephosphorylation using [?-32P]ATP.
  • Transport assays in intact cells: Including K+-mediated 86Rb uptake.
  • Flame photometry: Measurements of intracellular Na+ and K+ concentrations.

Collaborators and centres

  • Professor Bente Vilsen, Department of Biomedicine, Aarhus University, Denmark
  • Professor Jens Peter Andersen, Department of Biomedicine, Aarhus University, Denmark
  • Professor Torben Clausen, Department of Biomedicine, Aarhus University, Denmark
  • Interdisciplinary Center for Membrane Proteins: MEMBRANES at Aarhus University, Denmark

Research group members

 

 

Group leader

Publications

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Revideret 20.09.2017