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AKB: Biologische Physik

AKB 1: Cellular Processes

AKB 1.2: Vortrag

Montag, 27. März 2006, 10:30–10:45, ZEU 255

Mechanics and dynamics of actin ring constriction during cytokinesis: The role of filament polymerization — •Alexander Zumdieck, Karsten Kruse, and Frank Jülicher — MPI-PKS, Nöthnitzer Str. 38, Dresden

The cytoskeleton is a complex network of protein filaments. Driven by active processes such as filament polymerization and depolymerization and the action of molecular motors it represents an active, soft material. It is intrinsically dynamic and able to generate mechanical stress and flow of filaments.

We present a theoretical description of the dynamics and mechanics of contractile actin rings, important cytoskeletal structures, which constrict cells during cytokinesis. Quantitative comparison of experimental data together with a phenomenological description of ring contraction allows us to estimate the essential parameters characterizing mechanics and dynamics of a contracting ring. We discuss in particular the cell elastic modulus, the mechanical stress generated by the ring as well as the filament density in the ring and the rates of filament turnover.

Using a more microscopic description of filament interactions in the ring, we identify physical mechanisms of ring contraction driven by motors and filament turnover. In particular we discuss how filament bundles may generate tension in the absence of molecular motors.