A5037010286- Cell death mechanisms and regulation
- Electron Spin Resonance Studies
- Lipid Membrane Structure and Behavior
- ATP Synthase and ATPases Research
- RNA Interference and Gene Delivery
- Lanthanide and Transition Metal Complexes
- Mitochondrial Function and Pathology
- Magnetism in coordination complexes
- Advanced NMR Techniques and Applications
- Cellular transport and secretion
- Fibroblast Growth Factor Research
- Macrophage Migration Inhibitory Factor
- Erythrocyte Function and Pathophysiology
- Analytical Chemistry and Chromatography
- Proteoglycans and glycosaminoglycans research
- Supramolecular Self-Assembly in Materials
- Ubiquitin and proteasome pathways
- Molecular Sensors and Ion Detection
- thermodynamics and calorimetric analyses
- Hippo pathway signaling and YAP/TAZ
- Computational Drug Discovery Methods
- Alkaline Phosphatase Research Studies
- Electrochemical Analysis and Applications
- Advanced MRI Techniques and Applications
- Nuclear Receptors and Signaling
Ruhr University Bochum
2017-2020
Max Planck Institute for Intelligent Systems
2012-2017
University of Tübingen
2014-2017
German Cancer Research Center
2012-2014
Heidelberg University
2012-2014
Max Planck Society
2009-2013
University of Nicosia
2013
Max Planck Institute of Biochemistry
2009-2012
Bax and Bid are pro-apoptotic members of the Bcl-2 protein family. Upon cleavage by caspase-8, activates Bax. Activated inserts into mitochondrial outer membrane forming oligomers which lead to poration, release cytochrome c, apoptosis. The detailed mechanism activation topology composition still under debate. Here molecular details oligomerization were obtained application several biophysical techniques, including atomic force microscopy, cryoelectron particularly electron paramagnetic...
Abstract Bax is a key regulator of apoptosis that mediates the release cytochrome c to cytosol via oligomerization in outer mitochondrial membrane before pore formation. However, molecular mechanism assembly and regulation by other Bcl-2 members remains obscure. Here, analysing stoichiometry oligomers at single-molecule level, we find binds monomeric state then self-assembles <1 min. Strikingly, active does not exist unique oligomeric state, but as several different species based on dimer...
Fibroblast growth factor 2 (FGF2) is a critical mitogen with central role in specific steps of tumor-induced angiogenesis. It known to be secreted by unconventional means bypassing the endoplasmic reticulum/Golgi-dependent secretory pathway. However, mechanism FGF2 membrane translocation into extracellular space has remained elusive. Here, we show that phosphatidylinositol 4,5-bisphosphate-dependent recruitment causes oligomerize, which turn triggers formation lipidic pore putative toroidal...
The Bcl-2 proteins form a complex interaction network that controls mitochondrial permeabilization and apoptosis. relative importance of different complexes their spatio-temporal regulation is debated. Using fluorescence cross-correlation spectroscopy to quantify the interactions within minimal network, comprised by cBid, Bax, Bcl-xL, we show membrane insertion drastically alters pattern complexes, C-terminal helix Bcl-xL determines its binding preferences. At physiological temperature, Bax...
Fibroblast growth factor 2 (FGF2) is a key signaling molecule in tumor-induced angiogenesis. FGF2 secreted by an unconventional secretory mechanism that involves phosphatidylinositol 4,5-bisphosphate-dependent insertion of oligomers into the plasma membrane. This process regulated Tec kinase-mediated tyrosine phosphorylation FGF2. Molecular interactions driving monomers membrane-inserted are unknown. Here we identify two surface cysteines critical for efficient secretion They represent...
Abstract The availability of bioresistant spin labels is crucial for the optimization site‐directed labeling protocols EPR structural studies biomolecules in a cellular context. As can affect proteins’ fold and/or function, having possibility to choose between different will increase probability produce spin‐labeled functional proteins. Here, we report synthesis and characterization iodoacetamide‐ maleimide‐functionalized based on gem ‐diethyl pyrroline structure. two nitroxide are compared...
Abstract The proteins of the Bcl-2 family have a crucial role in mitochondrial outer membrane permeabilization during apoptosis and regulation dynamics. Current models consider that Bax forms toroidal pores at mitochondria are responsible for release cytochrome c, whereas Bcl-xL inhibits pore formation. However, how regulate fission fusion remains poorly understood. By using systematic analysis single vesicle level, we found cBid, able to remodel membranes different ways. cBid induced...
Abstract Bax is a Bcl-2 protein crucial for apoptosis initiation and execution, whose active conformation only partially understood. Dipolar EPR spectroscopy has proven to be valuable tool determine coarse-grained models of membrane-embedded proteins. Here we show how the combination spectroscopically distinguishable nitroxide gadolinium spin labels Double Electron-Electron Resonance can help gain new insights into quaternary structure active, oligomers. We that attaching bulkier than...
The BH3-only protein Bid plays a key role in the induction of mitochondrial apoptosis, but its mechanism action is still not completely understood. Here we studied two main activation events Bid: Caspase-8 cleavage and interaction with membrane bilayer. We found striking reversible behaviour dissociation-association between fragments p15 p7. does induce per se separation fragments, which remain stable complex resembling full length Bid. Detergents trigger complete dissociation, can be fully...
Abstract Motivation: In order to obtain statistically relevant results, the study of membrane effects at single-vesicle level requires analysis several hundreds giant unilamellar vesicles (GUVs), which becomes a very time-consuming task if carried out manually. Complete and user-friendly software for fast bias-free automated has not been reported yet. Results: We developed framework detection, tracking individual GUVs on digital microscopy images. Our tool is suited quantify protein binding...
Pro-apoptotic Bax is a soluble and monomeric protein under normal physiological conditions. Upon its activation substantial structural rearrangements occur: The inserts into the mitochondrial outer membrane forms higher molecular weight oligomers. Subsequently, cells can undergo apoptosis. In our studies, we focused on of during oligomerization stability. Both conformations exhibit high stability against thermal denaturation, chemically induced unfolding proteolytic processing. oligomeric...
Abstract Invited for this month's cover picture is the group of Professor Enrica Bordignon at Ruhr University Bochum. The shows an artistic view E. coli cells and two spin‐labeled recombinantly produced proteins, which can be inserted into EPR studies. primary sequence proteins schematically shown with one‐letter amino acid code, cysteine residues are functionalized new gem diethyl nitroxide spin labels designed to better sustain reducing cellular environment. Read full text their Full Paper...
Apoptosis regulation by Bcl-2 proteins is pivotal for mammalians, not only because it key development but also aberrant apoptosis prerequisite to severe diseases, like cancer. Recently, we quantified interactions within the protein network in solution and membranes, addressed membrane recruitment, preference of interaction partners consequences Bax activation inhibition.