Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 22: Posters: Cytoskeletal filaments

BP 22.4: Poster

Dienstag, 17. März 2015, 14:00–16:00, Poster A

Investigation of vimentin assembly and aggregation in continuous and segmented flow by small angle X-ray scattering — •Oliva Saldanha, Martha Brennich, Clément Hémonnot, Rita Graceffa, and Sarah Köster — Institute for X-ray Physics, Uni Göttingen

Intermediate filaments (IFs) are fibrous cytoskeletal proteins, which provide mechanical support in metazoan cells. These proteins (along with actin filaments and microtubules) play a crucial role in cell mechanics and stability. In cells, IFs form distinct bundle and network structures but the precise assembly mechanisms are not yet fully understood. In vitro, rod-like IF monomers self-assemble in a hierarchical manner to form filaments with a diameter of about 10 nm and, subsequently, bundles and networks. In vitro, upon the addition of divalent salts (such as MgCl2), bundling and network formation is initiated. We employ small angle X-ray scattering (SAXS) to study vimentin assembly and network formation on millisecond to second time scales in continuous microflow as well as in microfluidic droplets. Microfluidics offers the possibility to mix in different types of ions successively and with precise control. Droplet microfluidics enables us to encapsulate the micro-reaction in a unique aqueous-in-oil environment. Both complementary approaches ensure decreased radiation damage and higher signal-to-noise ratio by longer accumulative exposure times. Given the sensitivity of SAXS measurements to the size of the molecular aggregates, we can distinguish between different stages of the assembly process and relate the results to the flow conditions in the device.