"We currently seek for highly motivated students in Biology, Bioinformatics, Physics, or a related research area to perform a Master thesis in our group. If you are interested please contact PD Dr. U. Terpitz."
|Since 2011||Lecturer and Groupleader, Department of Biotechnology & Biophysics(Biocenter), University of Würzburg, Germany|
|2009-2011||Postdoctoral Researcher, Max-Planck-Institute of Biophysics, Frankfurt am Main, Germany|
|2005-2009||PhD in Biochemistry, Johann-Wolfgang-Goethe University and Max-Planck-Institute of Biophysics, Frankfurt am Main, Germany|
|2004||Research Assistant, University of Morelos, Cuernavaca, Mexico|
|2001-2004||Study of Biology, Friedrich-Schiller-University Jena, Germany|
|1998-2001||Study of Biology, University of Hamburg, Germany|
We combine super-resolution microscopy and electrophysiology (Patch-clamp technique) in order to understand the dynamics, interaction, and gating of membrane proteins and the interaction of microbes with their environment and other organisms. In our mechanistic studies we focus on light-gated membrane proteins, especially fungal rhodopsins. Although these green-light sensing proteins are widespread in the fungal kingdom, little is known about their physiological function and distribution in the hyphae. Within the collaborative research centre TR124 FungiNet (project A3) we use fluorescence microscopy for unravelling the interaction between innate immune cells and Aspergillus fumigatus or Lichtheimia corymbifera. Due to their tiny size and their often strong autofluorescence, fluorescence microscopy of fungi is challenging, but we recently established and currently optimize protocols for the visualisation of hyphae and spores. Another focus of our group is in developing optogenetical tools allowing for the analysis of physiological downstream processes upon light-trigger in isolated cells.
Microbial rhodopsins are widespread in the fungal kingdom and consist of seven transmembrane helices forming an interior pocket for the chromophore all-trans retinal, which is covalently bound to the protein via a protonated Schiff-base. Though it is known that upon light-activation fungal rhodopsins act as proton pumps or sensory proteins, detailed knowledge of their physiological function and biological role is still missing. As many substantial processes in filamentous fungi such as reproduction and pathogenicity are controlled by light, in this project we aim to unravel the task of these green light sensors in fungi.
Recently, we analysed the molecular function of elected fungal rhodopsins and gained insights into the biological and physiological function of the rhodopsin CarO of the rice pathogen Fusarium fujikuroi. Our data for the first time show a clear phenotype of a rhodopsin-deficient fungus, suggesting a role of rhodopsins in conidia germination and the fungus-plant interaction. Currently we combine a number of interdisciplinary methods to analyse the function of rhodopsins in the fungi F. fujikuroi and Ustilago maydis, which both are of economic relevance and cause severe plant disease.
García-Martínez et al., Sci. Rep.5, 7798 (2015); Brunk et al., Sci. Rep. 8, 605 (2018); Adam et al., Int. J. Mol. Sci., 19, 215 (2018)
Our group joined the CRC/TR 124 FungiNet in project A3 in the second funding period. This collaborative research centre combines the expertise of researchers in Jena and Würzburg and aims to decipher common principles of fungal pathogenesis and infection in the interplay with the innate immunity and adaptive immune system. In the long-term perspective the gained information will be used for the development of new therapeutic approaches. This is especially important, as the number of life-threatening infections due to opportunistic fungal pathogens has drastically increased over the past two decades, whereas the clinical diagnosis of these often mortal infections is still very difficult. In the recent past we developed a number of protocols suitable for the visualisation of fungi by super-resolved fluorescence techniques, now applied for the analysis of the interaction of immune cells and fungi.
The project A3 aims to uncover the key players of secondary immune defence mechanisms in neutropenic and/or alveolar macrophage-depleted conditions against A. fumigatus to uncover how these cells contribute to the regulation of inflammation and fungal clearance. We use super-resolution microscopy to unravel A. fumigatus-host myeloid cell interactions at the cellular and molecular level. Especially we will investigate quantitatively how receptors are organized and how they interact at the molecular level. From such investigations, we are able to improve our knowledge of the relations between receptor localization, receptor abundance, and receptor functionality, which is key to understanding how alterations of malfunction of any of these parameters can lead to mycosis and diverse other diseases.
Ziegler et al., Sci. Rep. 7, 6238 (2017)
We recently developed an implementation for the open source software ImageJ called “HyphaTracker”, allowing for computer-assisted analysis of fungal area alteration over time. This plugin is optimized for the analysis of germinating spores and allows for automatic area analysis of the fungal germlings after manual image processing. HyphaTracker allows for analysing the germination profile of the conidia of rhodopsin-deficient F. fujikuroi strains versus their reference strains and by that for revealing differences in the dynamics of the conidia germination. Before performing area analysis, the application filters the recordings and excludes particles and crossing hyphae from the analysis (Fig. 3).
The imageJ toolbox “HyphaTracker” can be downloaded here.
Brunk et al., Sci. Rep. 8, 605 (2018)
Ca2+ is a key signal in cell regulation, modulating the activity of a plenitude of sensitive proteins. Prerequisite for accurate signalling is the exact buffering of Ca2+ concentrations within the cell. The steep Ca2+ gradients between the cytosol (100 nM), endosomes (4-40 μM), lysosomes (~500 μM), and the extracellular lumen (~1 mM) allow for the generation of fast, spatially, and temporally modulated Ca2+ signals.
We developed an optochemokine tandem to control the release of Ca2+ from endosomes into the cytosol by light and to analyse the internalization kinetics of G-protein coupled receptors (GPCRs) by electrophysiology (Fig. 4). The light-gated Ca2+-permeable cation channel ChR2(L132C), CatCh was combined with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas. As shown by patch-clamp measurements and confocal laser scanning microscopy, heterologously expressed tCXCR4/CatCh was internalized via the endocytic SDF1/CXCR4 signalling pathway. The kinetics of internalization was followed electrophysiologically via the amplitude of the CatCh signal. The light-induced release of Ca2+ by tandem endosomes into the cytosol via CatCh was visualized using the Ca2+- sensitive dye rhod2(AM) showing an increase of intracellular Ca2+ in response to light.
Kleinlogel et al., Nat. Meth. 8, 1083-1088 (2011); Feldbauer et al., PLoS ONE 11(10): e0165344 (2016)
Adam, A., Deimel, S., Pardo-Medina, J., García-Martínez, J., Konte, T., Limón, M., Avalos, J., Terpitz, U.: Protein Activity of the Fusarium fujikuroi Rhodopsins CarO and OpsA and Their Relation to Fungus–Plant Interaction.International Journal of Molecular Sciences.19,215 (2018)
Brunk, M., Sputh, S., Doose, S., van de Linde, S., Terpitz, U.: HyphaTracker: An ImageJ toolbox for time-resolved analysis of spore germination in filamentous fungi. Sci. Rep. 8, 605 (2018).
Feldbauer, K., Schlegel, J., Weissbecker, J., Sauer, F., Wood, P.G., Bamberg, E., Terpitz, U., Optochemokine Tandem for Light-Control of Intracellular Ca2+. PLoS ONE 11(10): e0165344 (2016)
García-Martínez, J., Brunk, M., Avalos, J., and Terpitz, U., The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination. Sci. Rep. 5, 7798 (2015)
Kleinlogel, S., Terpitz, U., Legrum, B., Gökbuget, D., Boyden, E. S., Bamann, C., Wood, P. G., and Bamberg, E., A gene-fusion strategy for stoichiometric and co-localized expression of light-gated membrane proteins. Nature Meth. 8, 1083-1088 (2011)
Ziegler, S., Weiss, E., Schmitt, A.-L., Schlegel, J., Burgert, A., Terpitz, U., Sauer, M., Moretta, L., Sivori, S., Leonhardt, I., Kurzai, O., Einsele, H., Loeffler, J.: CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells.Scientific Reports.7,6138 (2017)