Tracking the dynamics of individual keratin filaments (poster)

• Dmytro Kotsur
• Roman Yakobenchuk
• R. E. Leube
• Julian Mattes
• R. Windoffer

Keratin networks have a dominant impact on the mechanical properties of epithelial cells. Surprisingly the cellular keratin network topology is quite variable between different tissues and cell types. The most obvious differences occur in the amount of filament bundling and branching. Within the keratin network of a single cell three major organization-types of filaments can be observed. A very prominent structure observed in most epithelial cell types in culture and in tissue is a well-defined nuclear cage. These fibers show a regularly branching and relatively less reorganization over time. The second class are radial keratin fibers that connect desmosomes to the perinuclear keratin network. These fibers can become quite prominent and may rearrange under changing mechanical load. A third class is arranged more or less concentrically around the nucleus and parallel to the cell border. These fibers are more diverse as they show a wide variation in branching and bundling. This group is quite dynamic and reorganized in a cycle of assembly and disassembly. To further characterize these three classes of filaments we have developed an image analysis tool that allows us to automatically track individual filaments in fluorescently labelled living cells over time and determine their movements and deformations. This allows us to extract motion relevant parameters for classification and analysis of different filament subgroups within living cells.