Regensburg 2013 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 12: Molecular Motors
BP 12.4: Vortrag
Dienstag, 12. März 2013, 10:30–10:45, H43
Positioning of microtubule organizing centers by cortical pushing and pulling forces — •Nenad Pavin1,2, Liedewij Laan3, Rui Ma1,4, Marileen Dogterom3, and Frank Jülicher1 — 1MPI-PKS, Dresden, Germany — 2University of Zagreb, Zagreb, Croatia — 3AMOLF, Amsterdam, The Netherlands — 4Tsinghua University, Beijing, China
Positioning of microtubule organizing centers (MTOC) with respect to the confining geometry of cells depends on pushing and/or pulling forces generated by MTs that interact with the cell cortex. How, in living cells, these forces lead to proper positioning is still largely an open question. Using in vitro experiments in artificial microchambers it was shown that in a square geometry, MT asters center more reliably by a combination of pulling and pushing forces than by pushing forces alone. Theoretically, we show that pulling and pushing forces acting on the MTOC in different geometries depend on orientations of MTs. We find that these forces can have centering or off-centering behavior in different geometries. Pushing forces center in a one-dimensional and a square geometry, but lead to off-centering in a circle if reorientation is sufficiently pronounced. Pulling forces, however, do not center in a one-dimensional geometry, but improve centering in a circle and a square. In an elongated stadium geometry, positioning along the short axis depends mainly on pulling forces, while positioning along the long axis depends mainly on pushing forces. Our theoretical results suggest that different positioning strategies could be used by different cell types (Laan et al 2012 Cell, Pavin et al NJP 2012).