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General Information

The BioInterface Seminars take place in seminar room Sem.R. DB gelb 07 (Freihaus, yellow area, 7th floor) on friday afternoons (13:30-16:30). This semester, the seminar will start with the students' talks followed by a talk given by the invited speaker. We intend to create an open space for discussions and exchange of experiences. Feel free to join- there will be snacks and drinks!



(08.11.2019) Stefan Scheiner: Bone remodeling studied by means of a coupled systems biology and multiscale bone mechanobiology approach



Schedule

Date of Seminar
External Speaker
Title of Seminar
Internal Speakers
2 PhD students per Seminar (20 min. each)
11.10.2019 Heinrich Krobath
(JKU Linz)
Thermal membrane undulations affect equilibrium binding and domain stability of membrane proteins in adhesion zones Joschka Hellmeier
Agnes Dobos
08.11.2019 Stefan Scheiner
(TU Wien)
Bone remodeling studied by means of a coupled systems biology and multiscale bone mechanobiology approach Iris Dorner
Valentina Wittner
06.12.2019 TBA
(University)
TBA Stefan Helfert
Raffaela Conceicao
10.01.2020 TBA
(University)
TBA Susanne Wagner
Andreas Rohatschek
06.03.2020 TBA
(University)
TBA Tobia Cavalli
Clara Bodner


Past Talks

(11.10.2019) Heinrich Krobath: Thermal membrane undulations affect equilibrium binding and domain stability of membrane proteins in adhesion zones

Abstract: Membrane protein binding and unbinding processes stand out as a reliable means of intercellular adhesion-based signal transduction. Based Helfrich’s elastic membrane model [1], we attempt to shed light on the subtle effects of thermal membrane undulations on equilibrium binding and domain formation of membrane-anchored proteins maintaining a cellular adhesion zone. Devising a statistical mechanics approach supported by Monte-Carlo (MC) simulations [2], we find that successful receptor-ligand binding locally encourages the establishment of proximal bound complexes. This mechanistic picture entails a local cooperative law of mass action for receptor-ligand interactions in membrane adhesion zones [3]. On the other hand, we present an extension of this adhesion model reminiscent of the immunological synapse containing two pairs of receptors and ligands – e.g. pMHC-TCR and LFA/ICAM – differing in size and binding affinity. In such a setting, stable domain formation is possible. We corroborate the existence of a critical point [4] of domain formation caused by membrane shape fluctuations and use classical nucleation theory to derive stability criteria for co-existing micro-domains. In this context, we show that membrane undulations increase the energetic penalty for domain formation by modulating line tension scaling near the critical point [5]. These thermally stable micro-domains may merge to macroscopic domains conducive to immunological synapse formation.

References:

[1] TR Weikl, M Asfaw, H Krobath, et al. Soft Matter, 2009, 5(17):3213-3224.

[2] H Krobath, GJ Schütz, R Lipowsky, TR Weikl. Europhys Lett., 2007, 78:38003

[3] H Krobath, B Różycki, R Lipowsky, TR Weikl. Soft Matter, 2009, 5:3354-3361.

[4] M Asfaw, B Różycki, R Lipowsky, TR Weikl. Europhys Lett., 2006, 76(4):703-709.

[5] H Krobath, B Różycki, R Lipowsky, TR Weikl. PLoS ONE, 2011, 6(8): e23284.