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Start Over Author "Felix Wolf" Publication Type Academic Journals
62 results on '"Felix Wolf"'

2. Building a realistic, scalable memory model with independent engrams using a homeostatic mechanism

Author

Marvin Kaster, Fabian Czappa, Markus Butz-Ostendorf, and Felix Wolf

Subjects
learning, memory, homeostatic plasticity, structural plasticity, scalable, Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571
Abstract

Memory formation is usually associated with Hebbian learning and synaptic plasticity, which changes the synaptic strengths but omits structural changes. A recent study suggests that structural plasticity can also lead to silent memory engrams, reproducing a conditioned learning paradigm with neuron ensembles. However, this study is limited by its way of synapse formation, enabling the formation of only one memory engram. Overcoming this, our model allows the formation of many engrams simultaneously while retaining high neurophysiological accuracy, e.g., as found in cortical columns. We achieve this by substituting the random synapse formation with the Model of Structural Plasticity. As a homeostatic model, neurons regulate their activity by growing and pruning synaptic elements based on their current activity. Utilizing synapse formation based on the Euclidean distance between the neurons with a scalable algorithm allows us to easily simulate 4 million neurons with 343 memory engrams. These engrams do not interfere with one another by default, yet we can change the simulation parameters to form long-reaching associations. Our model's analysis shows that homeostatic engram formation requires a certain spatiotemporal order of events. It predicts that synaptic pruning precedes and enables synaptic engram formation and that it does not occur as a mere compensatory response to enduring synapse potentiation as in Hebbian plasticity with synaptic scaling. Our model paves the way for simulations addressing further inquiries, ranging from memory chains and hierarchies to complex memory systems comprising areas with different learning mechanisms.

Published
2024
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3. Warhead biosynthesis and the origin of structural diversity in hydroxamate metalloproteinase inhibitors

Author

Franziska Leipoldt, Javier Santos-Aberturas, Dennis P. Stegmann, Felix Wolf, Andreas Kulik, Rodney Lacret, Désirée Popadić, Daniela Keinhörster, Norbert Kirchner, Paulina Bekiesch, Harald Gross, Andrew W. Truman, and Leonard Kaysser

Subjects
Science
Abstract

Metalloproteinase inhibitors are leads for drug development, but their biosynthetic pathways are often unknown. Here the authors show that the acyl branched warhead of actinonin and matlystatins derives from an ethylmalonyl-CoA-like pathway and the structural diversity of matlystatins is due to the activity of a decarboxylase-dehydrogenase enzyme.

Published
2017
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4. Phosphorylation-Dependent Differences in CXCR4-LASP1-AKT1 Interaction between Breast Cancer and Chronic Myeloid Leukemia

Author

Elke Butt, Katrin Stempfle, Lorenz Lister, Felix Wolf, Marcella Kraft, Andreas B. Herrmann, Cristina Perpina Viciano, Christian Weber, Andreas Hochhaus, Thomas Ernst, Carsten Hoffmann, Alma Zernecke, and Jochen J. Frietsch

Subjects
lasp1, cxcr4, akt1, cml, breast cancer, Cytology, QH573-671
Abstract

The serine/threonine protein kinase AKT1 is a downstream target of the chemokine receptor 4 (CXCR4), and both proteins play a central role in the modulation of diverse cellular processes, including proliferation and cell survival. While in chronic myeloid leukemia (CML) the CXCR4 is downregulated, thereby promoting the mobilization of progenitor cells into blood, the receptor is highly expressed in breast cancer cells, favoring the migratory capacity of these cells. Recently, the LIM and SH3 domain protein 1 (LASP1) has been described as a novel CXCR4 binding partner and as a promoter of the PI3K/AKT pathway. In this study, we uncovered a direct binding of LASP1, phosphorylated at S146, to both CXCR4 and AKT1, as shown by immunoprecipitation assays, pull-down experiments, and immunohistochemistry data. In contrast, phosphorylation of LASP1 at Y171 abrogated these interactions, suggesting that both LASP1 phospho-forms interact. Finally, findings demonstrating different phosphorylation patterns of LASP1 in breast cancer and chronic myeloid leukemia may have implications for CXCR4 function and tyrosine kinase inhibitor treatment.

Published
2020
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5. Malleability in Modern HPC Systems: Current Experiences, Challenges, and Future Opportunities.

Author

Ahmad Tarraf, Martin Schreiber 0001, Alberto Cascajo, Jean-Baptiste Besnard, Marc-André Vef, Dominik Huber, Sonja Happ, André Brinkmann, David E. Singh, Hans-Christian Hoppe, Alberto Miranda, Antonio J. Peña, Rui Machado, Marta Garcia-Gasulla, Martin Schulz 0001, Paul M. Carpenter, Simon Pickartz, Tiberiu Rotaru, Sergio Iserte, Víctor López 0003, Jorge Ejarque, Heena Sirwani, Jesús Carretero 0001, and Felix Wolf 0001

Published
2024
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43. Interoperation of world-wide production e-Science infrastructures.

Author

Morris Riedel, Erwin Laure, Thomas Soddemann, Laurence Field, John-Paul Navarro, James Casey, Maarten Litmaath, Jean-Philippe Baud, Birger Koblitz, Charlie Catlett, Dane Skow, Cindy Zheng, Philip M. Papadopoulos, Mason J. Katz, Neha Sharma 0001, Oxana Smirnova, Balázs Kónya, Peter W. Arzberger, Frank Würthwein, Abhishek Singh Rana, Terrence Martin, M. Wan, Von Welch, Tony Rimovsky, Steven J. Newhouse, Andrea Vanni, Yoshio Tanaka, Yusuke Tanimura, Tsutomu Ikegami, David Abramson 0001, Colin Enticott, Graham Jenkins, Ruth Pordes, Steven Timm, Gidon Moont, Mona Aggarwal, D. Colling, Olivier van der Aa, Alex Sim, Vijaya Natarajan, Arie Shoshani, Junmin Gu, S. Chen, Gerson Galang, Riccardo Zappi, Luca Magnoni, Vincenzo Ciaschini, Michele Pace, Valerio Venturi, Moreno Marzolla, Paolo Andreetto, Robert Cowles, Shaowen Wang, Yuji Saeki, Hitoshi Sato, Satoshi Matsuoka, Putchong Uthayopas, Somsak Sriprayoonsakul, Oscar Koeroo, Matthew Viljoen, Laura Pearlman, Stephen Pickles, David Wallom, Glenn Moloney, Jerome Lauret, Jim Marsteller, Paul Sheldon, Surya Pathak, Shaun De Witt, Jirí Mencák, Jens Jensen, Matt Hodges, Derek Ross, Sugree Phatanapherom, Gilbert Netzer, Anders Rhod Gregersen, Mike Jones 0002, Péter Kacsuk, Achim Streit, Daniel Mallmann, Felix Wolf 0001, Thomas Lippert, Thierry Delaitre, Eduardo Huedo, and Neil Geddes

Published
2009
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