Figure 3. Dynein-mediated pulling and MT slipping lead to centrosome centering in a square chamber. (A) Artistic view of the experiment. Microtubules grow from a centrosome in a microfabricated chamber as described previously.²⁰ Dynein molecules are attached to a gold layer in the walls of the chambers. (B) Spinning disk confocal fluorescence images of MTs grown from centrosome in square chambers (side lengths: 15 μm), in absence (upper), or presence (lower) of dynein at the walls.²⁰ (C) Cartoon showing the net pulling force without (upper) and with (lower) MT slipping in a square geometry. (D) Evidence for MT slipping in vitro. A MT grows against a dynein coated barrier, slips and is then captured by dynein at the barrier. The gold barrier is indicated by the yellow line. Scale bar: 10 μm.