Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 2: Physics of Cells I

BP 2.2: Vortrag

Montag, 26. März 2012, 10:00–10:15, H 1028

Mixing dynamics of the actin cytoskeleton in motile cells — •Matthias Gerhardt, Michael Walz, and Carsten Beta — Institut für Physik und Astronomie, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam-Golm, Germany

We investigate the dynamics of the actin cytoskeleton during and immediately after electrofusion of cells of the social amoeba Dictyostelium discoideum. Two cell lines are used, one expressing a green (GFP) the other one a red fluorescent protein (mRFP) linked to a Lim-domain protein that serves as a marker for filamentous actin. Using a custom designed fusion chamber mounted on a confocal microscope, we are able to study the mixing dynamics of the actin cytoskeleton during cell fusion. The fusion process typically proceeds via three stages: I.) The early state is characterized by an initial pore, which connects the cells. F-actin fragments with a green label invade the cell expressing the red label and vica versa. II.) In the intermediate state, the cells are connected by a junction of hour-glass shape. The actin cytoskeleton starts mixing, resulting in a yellow overlay of the two labels. III.) The final state is characterized by a completely mixed actin cytoskeleton in a fused cell. The timescale of mixing and remodeling of the cytoskeleton is surprisingly short, indicating that the active, self-organized processes in the actin cytoskeleton quickly integrate constituents of both cells into one overall cortex of the fused cell.