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Center of Cellular Nanoanalytics Osnabrück


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C: Qualitative and quantitative analytics of composition and interactions


Projects

Analysis of sphingolipid levels from different yeast mutants by mass spectrometry based lipidomics (Fröhlich et al., Elife 2015)

C1: Molecular Membrane Biology - Mechanisms of sphingolipid and sterol homeostasis in Sacchomyces cerevisiae

Florian Fröhlich, Biology

Research of the Fröhlich group is focused upon sphingolipid and sterol homeostasis in the model organism Saccharomyces cerevisiae. To this end we investigate the sorting of lipids throughout the endocytic pathway and how these processes are regulated. In addition to the classic methods of cell biology we use proteomics, lipidomics, and systematic screenings. Unraveling these basic mechanisms will be the foundation to understand neurodegenerative disorders which are caused by the dysregulation of sphingolipid and sterol homeostasis.

Cluster mapping of sensor complexes at the cell surface of yeast cells (left) and mechanical properties of single sensors measured via atomic force microscopy and spectroscopy (right) (Dupres et al., Nat. Chem. Biol., 2009).

C2: Signal transduction in the yeast cell wall integrity pathway

Jürgen Heinisch, Biology

Description coming soon...

C3: Pathogen-host interactions

Michael Hensel, Biology

Description coming soon...

C4: Metabolic cross-feeding interactions

Christian Kost, Biology

The Kost group studies cooperative cross-feeding interactions among different bacterial cells. For this, metabolite concentrations in- and outside bacterial cells as well as activities of the underlying metabolic pathways need to be determined. The group establishes protocols to accurately quantify metabolite concentrations using tools of analytical chemistry or genetically-encoded, intracellular biosensors. By analyzing both fluxes through the cells’ metabolic networks and the transcriptomes of individual cells or entire consortia, quantitative insights into the focal metabolic interactions can be derived.

HRTEM images of {Mn4}-complexes on CNTs (left) and of C60 within CNTs (center). Right: AFM image of a CNT-FET with sketch of a TERS tip

C6: Electronic Transport - Ultra-Sensitive Sensors for Molecular and Nanoscale Phenomena

Carola Meyer, Physics

The group of Carola Meyer investigates upon electronic transport in carbon nanotubes  (CNTs) functionalized with molecules. We focus on molecular interactions to gain a deeper understanding of spin interactions and molecular dynamics in magnetic and biomolecules. This includes the fabrication of nano-devices, the synthesis and chemical functionalization of the CNTs, and their characterization using cutting edge microscopy and spectroscopy. Electronic transport is investigated in quantum transport, noise and magnetoresistance measurements.

Quantification of low-affinity protein interactions by tethering to phase-separated plymer-supported membranes (Beutel et al., ACS Nano, 2015)

C7: Signal propagation across biological membranes - Surface architectures for quantitative interaction analysis

Jacob Piehler, Biology

The Piehler group develops surface modification techniques for functional tethering of proteins including the reconstitution of integral membrane proteins into polymer-supported membranes. By combination of microstructured surface functionalization with optically or chemically switchable molecular recognition, spatiotemporally controlled organization of proteins on surfaces and in membranes has been achieved. Recently, this method has been extended to capturing proteins in the plasma membrane of living cells. These surface architectures offer versatile opportunities for quantitative biomolecular interaction analysis by a broad spectrum of spectroscopic and microscopic detection techniques as established in the group.

Scanning electron microscopy image showing a fibroblast grown on an artificial array of aligned polymer nanorods (Grimm et al., J. Mater. Chem. 2010)

C8: Mesoscopic structure formation - Functional micro- and nanostructured surfaces

Martin Steinhart, Chemistry

The Steinhart group investigates upon the design of topographically patterned surfaces to be used as synthetic biological interfaces. The topographic surface patterns may be combined with nanoscopic fine structures which represent additional functional hierarchical structure levels. Examples for surfaces with topographies tailored such as to control cellular interactions or adhesive properties include nanorod arrays and monolithic microsphere arrays. Examples for additional hierarchical structure levels with nanoscale dimensions are continuous pore systems enabling supply of liquid to synthetic biological interfaces and gold nanostructures for surface enhanced Raman spectroscopy.

Distance distribution of the aspartate transporter Glt(Ph) in the presence (blue) and absence (black) of substrate as determined by DEER (Hänelt et al., Nat. Struct. Mol. Biol. 2013)

C9: Macromolecular structure - EPR spectroscopy of membrane proteins

Heinz-Jürgen Steinhoff, Physics
Johann Klare, Physics

The Steinhoff group studies the conformation and dynamics of biomolecules in order to understand their function on the atomic level. The group develops and applies advanced electron paramagnetic resonance (EPR) and double electron-electron resonance (DEER) methods in combination with site directed spin labeling, which are complemented by molecular dynamics simulations. The group focuses on exploring the functional mechanisms of transmembrane transport and signaling.

Measurement of membrane fusion with SNARE-proteoliposomes containing two fluorophores (top). Content mixing requires the Rab7-like Ypt7 and the activator MC1, as well as the hexameric HOPS complex (Langemeyer et al., 2018).

C10: Membrane remodeling in the endolysosomal system

Christian Ungermann, Biology

The Ungermann lab is interested in the fusion of membranes of the endolysosomal pathway in yeast and higher eukaryots. The group had developed protocols to purify and characterize large protein complexes involved in membrane fusion and membrane remodeling at endosomes and vacuoles. The group has established new in vitro assays to analyze the membrane association and the subsequent membrane fusion, and has experience on liposome-based interaction analyses. A further focus in the group is the in vivo analysis of endosomes and vacuoles, and their association with protein complexes to clarify protein dynamics and function within the endosomal system.

Single cell pull-down assay of individual cytosolic STAT1 (red)/STAT2 (green) complexes on a micropatterned surface (Wedeking, et al., Nano Lett. 2015)

C11: Surface biofunctionalization for quantification and manipulation of cell signaling

Changjiang You, Biology

The You group biofunctionalizes nanoparticles and planar substrates for the functional immobilization and lateral organization of proteins on surfaces. Monofunctionalization of quantum dots was successfully implemented for probing molecular and cellular determinants of cytokine signaling at single molecule level. Micropatterned biofunctionalized surfaces were developed for quantifying dynamics and stoichiometry protein-protein interactions involved in downstream signal propagation of cytokine receptor signaling. Currently, these tools are being expanded to spatiotemporally control the organization of signaling complexes in the plasma membrane of live cells.