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Review
. 2012 Oct 15;11(20):3750-7.
doi: 10.4161/cc.21753. Epub 2012 Aug 16.

End-on microtubule-dynein interactions and pulling-based positioning of microtubule organizing centers

Liedewij Laan  1 , Sophie Roth, Marileen Dogterom
Affiliations
Review

End-on microtubule-dynein interactions and pulling-based positioning of microtubule organizing centers

Liedewij Laan et al. Cell Cycle. .

Abstract

During important cellular processes such as centrosome and spindle positioning, dynein at the cortex interacts with dynamic microtubules in an apparent "end-on" fashion. It is well-established that dynein can generate forces by moving laterally along the microtubule lattice, but much less is known about dynein's interaction with dynamic microtubule ends. In this paper, we review recent in vitro experiments that show that dynein, attached to an artificial cortex, is able to capture microtubule ends, regulate microtubule dynamics and mediate the generation of pulling forces on shrinking microtubules. We further review existing ideas on the involvement of dynein-mediated cortical pulling forces in the positioning of microtubule organizing centers such as centrosomes. Recent in vitro experiments have demonstrated that cortical pulling forces in combination with pushing forces can lead to reliable centering of microtubule asters in quasi two-dimensional microfabricated chambers. In these experiments, pushing leads to slipping of microtubule ends along the chamber boundaries, resulting in an anisotropic distribution of cortical microtubule contacts that favors centering, once pulling force generators become engaged. This effect is predicted to be strongly geometry-dependent, and we therefore finally discuss ongoing efforts to repeat these experiments in three-dimensional, spherical and deformable geometries.

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Figures

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Figure 1. Dynein interacting with MT ends can generate pulling forces. (A) Schematic representation of the end-on interaction between cortical dynein and dynamic MTs during spindle positioning in C. elegans embryos. (B–C) In vitro reconstructions of the dynein-MT end-on interaction. (B) Barrier experiment: Dynein molecules are attached to a microfabricated gold barrier; MTs are growing from a purified centrosome, as described in detail previously. (Left) Schematic view of the experiment. (Right) Spinning disk confocal fluorescence microscopy images without or with dynein at the barrier. The gold barrier position is marked by a yellow line. Scale bars: 5 μm. (C) Optical tweezers experiment. Dynamic MTs are growing from axonemes attached to a trapped bead, and interact with dynein coated barriers, as described previously. Left: Schematic view of the experiment. Right: Growth and shrinkage of MTs interacting with an uncoated barrier (upper trace) or a dynein-coated barrier in presence (middle) or absence (lower) of ATP.
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Figure 2. Scenario’s for pulling-based centering of MTOCs. (A) Dynamic MTs lead to a length distribution of MTs that favors contacts with nearby boundaries. This leads to a net pulling force away from the center when all cortical contacts generate a pulling force (decentering). (B) When all MTs reach the boundaries, the net pulling force is zero (neutral) independent of the position of the MTOC in the confining space. (C) If only a limited number of cortical contacts generate a pulling force, the net pulling force is directed toward the center (centering). (D) When slipping of MTs along the boundaries of the confining space leads to an anisotropic distribution of MTs, the net pulling force is directed toward the center even when all cortical contacts generate a pulling force (centering).
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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. 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. (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.
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Figure 4. Dynein-mediated centrosome positioning in emulsion droplets and liposomes. (A–C) Centrosome positioning in emulsion droplets. (A) Cartoon of the experiment. Dynein molecules are linked to phospholipids at the surface of the droplet. (B–C) Preliminary experiments show that dynein molecules attached to phospholipids can either center (B) or decenter (C) asters. MTs (red) growing from a purified centrosome interact with dynein (green) at the edge of the droplets. Shown is a single Z-plane of a spinning disk confocal fluorescence stack. Scale bars: 10 µm. (D) Centrosome positioning in GUVs. Cartoon of the desired experiment. (E) Cartoon explaining the accumulation of dynein at the entrance of the protrusions created by free MTs. Red arrows point to the accumulations. (F–G) Free taxol-stabilized MTs grown in GUVs, with membrane-bound dynein molecules. Scale bar: 3 µm (F) Z-projection of fluorescent MTs. (G) Individual Z-planes of the GUV seen in (F). Shown is a superposition of the MT (red) and dynein (green) signals. Arrows indicate the positions of dynein accumulation at the entrance of the protrusions. Z spacing = 0.3 μm. Scale bar: 3 µm.
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References

    1. Tran PT, Marsh L, Doye V, Inoué S, Chang F. A mechanism for nuclear positioning in fission yeast based on microtubule pushing. J Cell Biol. 2001;153:397–411. doi: 10.1083/jcb.153.2.397. - DOI - PMC - PubMed
    1. Adames NR, Cooper JA. Microtubule interactions with the cell cortex causing nuclear movements in Saccharomyces cerevisiae. J Cell Biol. 2000;149:863–74. doi: 10.1083/jcb.149.4.863. - DOI - PMC - PubMed
    1. Kimura A, Onami S. Local cortical pulling-force repression switches centrosomal centration and posterior displacement in C. elegans. J Cell Biol. 2007;179:1347–54. doi: 10.1083/jcb.200706005. - DOI - PMC - PubMed
    1. Desai A, Mitchison TJ. Microtubule polymerization dynamics. Annu Rev Cell Dev Biol. 1997;13:83–117. doi: 10.1146/annurev.cellbio.13.1.83. - DOI - PubMed
    1. Wühr M, Dumont S, Groen AC, Needleman DJ, Mitchison TJ. How does a millimeter-sized cell find its center? Cell Cycle. 2009;8:1115–21. doi: 10.4161/cc.8.8.8150. - DOI - PMC - PubMed

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