ZMB Member Michael Ehrmann

ZMB Member
Michael Ehrmann

Next ZMB-Member
Michael Ehrmann portrait
© M. Ehrmann

Prof. Dr. Michael Ehrmann

Faculty of Biology
Center of Medical Biotechnology (ZMB)
University of Duisburg-Essen
Universitätsstr. 2
45141 Essen

Research Overview

Mechanism and Translational Aspects of Protein Quality Control
Each cell hosts thousands of different proteins that vary greatly in copy number and in their chemical properties. Despite this complication, nature has evolved efficient mechanisms of quality control to ensure that all proteins are biologically active, localised to the proper cellular compartment and present in appropriate quantity. This functional state must be maintained under normal as well as under stress conditions. The failure of quality control can influence cell growth and can cause severe diseases ranging for example from bacterial infections to neurodegenerative and arthritic diseases or cancer.
We are studying evolutionarily conserved cellular factors that are involved in key aspects of quality control, such as detection of misfolded proteins, signal recognition and integration into the unfolded protein response pathways and regeneration of the functional state. These studies aim at revealing the general concepts governing the underlying molecular mechanisms of protein diagnosis, repair and degradation.

The focus of our research is on the widely conserved HtrA family of serine proteases that are involved in all aspects of ATP-independent protein quality control. We showed that a protein can combine the antagonistic functions of chaperone and protease activities within a single polypeptide. Furthermore, in collaboration with Tim Clausen (IMP Vienna), it was shown that HtrAs can switch between various oligomeric states and the mechanism of activation by oligomerisation has been elucidated. In recent years, work on human HTRA1 has revealed its involvement in cancer (as a tumor suppressor), in arthritis (by remodelling of the extracellular matrix) and in Alzheimer's disease (by degrading proteins and protein fragments that aggregate to form senile plaques).
Since a number of years we are using chemical biology approaches, mainly in collaboration with Markus Kaiser (Uni Duisburg-Essen), Biotech and Pharmaceutical companies to generate tools for basic research and for drug development purposes. In addition, the structure of HTRA1 with a bound inhibitor provides leads for the search of HTRA1 modulators that are of therapeutic relevance.
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Selected Publications

    Journal articles

  • Poepsel, Simon; Sprengel, Andreas; Sacca, Barbara; Kaschani, Farnusch; Kaiser, Markus; Gatsogiannis, Christos; Raunser, Stefan; Clausen, Tim; Ehrmann, Michael
    Determinants of amyloid fibril degradation by the PDZ protease HTRA1
    In: Nature Chemical Biology Vol. 11 (2015) Nr. 11, pp. 862 - 869
  • Mastny, Markus; Heuck, Alexander; Kurzbauer, Robert; Heiduk, Anja; Boisguerin, Prisca; Volkmer, Rudolf; Ehrmann, Michael; Rodrigues, Christopher D.A.; Rudner, David Z.; Clausen, Tim
    XCtpB assembles a gated protease tunnel regulating cell-cell signaling during spore formation in bacillus subtilis
    In: Cell Vol. 155 (2013) Nr. 3, pp. 647 - 658
  • Malet, Hélène; Canellas, Flavia; Sawa, Justyna; Yan, Jun; Thalassinos, Konstantinos; Ehrmann, Michael; Clausen, Tim; Saibil, Helen R.
    Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ
    In: Nature Structural & Molecular Biology Vol. 19 (2012) Nr. 2, pp. 152 - 157
  • Clausen, Tim; Kaiser, Markus; Huber, Robert; Ehrmann, Michael
    HTRA proteases : regulated proteolysis in protein quality control
    In: Nature Reviews Molecular Cell Biology Vol. 12 (2011) Nr. 3, pp. 152 - 162
  • Merdanovic, Melisa; Clausen, Tim; Kaiser, Markus; Huber, Robert; Ehrmann, Michael
    Protein quality control in the bacterial periplasm
    In: Annual Review of Microbiology Vol. 65 (2011) pp. 149 - 168
  • Kley, Juliane; Schmidt, Bastian; Boyanov, Boril; Stolt-Bergner, Peggy C.; Kirk, Rebecca; Ehrmann, Michael; Knopf, Ronit R.; Naveh, Leah; Adam, Zach; Clausen, Tim
    Structural adaptation of the plant protease Deg1 to repair photosystem II during light exposure
    In: Nature Structural & Molecular Biology Vol. 18 (2011) Nr. 6, pp. 728 - 731
  • Trübestein, Linda; Tennstaedt, Annette; Mönig, Timon; Krojer, Tobias; Canellas, Flavia; Kaiser, Markus; Clausen, Tim; Ehrmann, Michael
    Substrate induced remodeling of the active site regulates human HtrA1 activity
    In: Nature Structural & Molecular Biology Vol. 18 (2011) pp. 386 - 388
  • Merdanovic, Melisa; Mamant, Nicolette; Meltzer, Michael; Poepsel, Simon; Auckenthaler, Alexandra; Melgaard, Rie; Hauske, Patrick; Nagel-Steger, Luitgard; Clarke, Anthony R.; Kaiser, Markus; Huber, Robert; Ehrmann, Michael
    Determinants of structural and functional plasticity of a widely conserved protease chaperone complex
    In: Nature Structural & Molecular Biology Vol. 17 (2010) Nr. 7, pp. 837 - 843
  • Hasenbein, Sonja; Merdanovic, Melisa; Ehrmann, Michael
    Determinants of regulated proteolysis in signal transduction
    In: Genes and Development Vol. 21 (2007) Nr. 1, pp. 6 - 10
  • Hasselblatt, Hanna; Kurzbauer, Robert; Wilken, Corinna; Krojer, Tobias; Sawa, Justyna; Kurt, Juliane; Kirk, Rebecca; Hasenbein, Sonja; Ehrmann, Michael; Clausen, Tim
    Regulation of the σE stress response by DegS: How the PDZ domain keeps the protease inactive in the resting state and allows integration of different OMP-derived stress signals upon folding stress
    In: Genes and Development Vol. 21 (2007) Nr. 20, pp. 2659 - 2670
  • Wilken, Corinna; Kitzing, Karina; Kurzbauer, Robert; Ehrmann, Michael; Clausen, Tim
    Crystal structure of the DegS stress sensor: How a PDZ domain recognizes misfolded protein and activates a protease
    In: Cell Vol. 117 (2004) Nr. 4, pp. 483 - 494
  • Ehrmann, Michael; Clausen, Tim
    Proteolysis as a regulatory mechanism
    In: Annual Review of Genetics Vol. 38 (2004) pp. 709 - 724
  • Krojer, Tobias; Garrido-Franco, Marta; Hubert, Robert; Ehrmann, Michael; Clausen, Tim
    Crystal structure of DegP (HtrA) reveals a new protease-chaperone machine
    In: Nature Vol. 416 (2002) Nr. 6879, pp. 455 - 459
  • Clausen, Tim; Southan, Chris; Ehrmann, Michael
    The HtrA family of proteases : Implications for protein composition and cell fate
    In: Molecular Cell Vol. 10 (2002) Nr. 3, pp. 443 - 455