Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 43: Cytoskeletal Filaments
BP 43.4: Vortrag
Mittwoch, 22. März 2017, 16:00–16:15, HÜL 386
Lateral association and elongation of vimentin intermediate filament proteins: A time-resolved light-scattering study — •Carlos Lopez1, Oliva Saldanha2, Klaus Huber1, and Sarah Köster2 — 1Department Chemie, Universität Paderborn, 33098 Paderborn, Germany — 2Institut für Röntgenphysik, Georg-August-Universitat Göttingen, 37077 Göttingen, Germany
Intermediate filaments constitute one of the three protein filament systems in the cytoskeleton of metazoa. Together with actin filaments and microtubules they form a sophisticated composite network, which has been identified as a main player in cell mechanics. The assembly pathway of the cytoskeletal protein vimentin may be responsible for the mechanical properties of the emerging filaments, such as high flexibility and extensibility, and thus play a key role in cellular mechanics.
Assembly of Vimentin from its tetrameric form can be triggered by addition of a monovalent salt. A two-step assembly mechanism: lateral association and a subsequent elongational step, has been established; however, the elongational step has not be followed in solution.
We present direct in situ observation and modeling of the elongation reaction of the filaments on the relevant length (60-600nm) and time scales, using time-resolved, multiangle static and dynamic light scattering. We thus achieve sufficient spatio-temporal resolution without the need of labeling, staining, or adsorption to substrates. The mass per unit length, hydrodynamic diameter and the end-to-end elongation rate constant of the assembling filaments are evaluated as a function of added salt.