Karsten Kruse - Physics of Cell Division
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Previous and current research
Subcellular processes during cell division are highly coordinated in space
and time. For example, in eukaryotes the division site is located between the
two newly forming nuclei and the cell is cleaved only after the chromosomes
have been distributed onto the future daughter cells. The cytoskeleton plays
an important part in these processes and cytoskeletal self-organization might
be a key element. Our group is interested in developing tools for analyzing
possible self-organization of cytoskeletal elements and in connecting the results
of the analysis to structures in vivo.
In the past we have developed several approaches for describing cytoskeletal
dynamics, ranging from microscopic models to a phenomenological description
of the dynamics on large space and time scales (hydrodynamic theory). In this
context we have studied in particular possible scenarios for the formation
of contractile rings and investigated conditions for the existence of microtubule
asters. The cytoskeleton is also important for the division of prokaryotes.
For example, in Escherichia coli, the Min-proteins, MinC, MinD, and MinE select
the cell centre as division site. This process involves pole-to-pole oscillations
of the Min-proteins, which are a consequence of continuous polymerization and
depolymerization of MinD-filaments. We have proposed a mechanism for the oscillations
that is based self-organization of the Min-proteins.
In tissues, cell division is in part regulated by external cues. In developing
organisms these cues involve in particular morphogens. Morphogens are molecules
that are secreted by a localized source from where they spread into the adjacent
tissue. There they form a gradient that imposes a spatial pattern because the
fate of a cell depends on the morphogen concentration it senses. The formation
of morphogen gradients is so far not well understood. There is evidence, that
building the gradient of Dpp in imaginal wing discs of Drosophila requires
transport of Dpp through cells. We have developed a description of this transport
process and are currently aiming at a quantitative comparison of theoretical
results and experimental observations.
Future prospects and goals
Our research plans include:
Quantitative description of the Min-oscillations in Escherichia coli
Analyzing the influence of polymerization and depolymerization of filaments on cytoskeletal dynamics
Application of the hydrodynamic theory of active polar gels to selected in vitro situations
Selected publications
Riedel, I.H., Kruse, K., and Howard, J. (2005): A self-organized vortex array of hydrodynamically entrained sperm cells. Science 309, 300.Grill, S.W., Kruse, K., and Jülicher, F. (2005): Theory of mitotic spindle oscillations. Phys. Rev. Lett. 94, 108104.
Meacci, G. and Kruse, K. (2005): Min-oscillations in Escherichia coli induced by interactions of membrane-bound proteins. Phys. Biol. 2, 89.
Kruse, K., Pantazis, P., Bollenbach, T., Jülicher, F., and González-Gaitán, M. (2004): Dpp gradient formation by dynamin-dependent endocytosis: receptor trafficking and the diffusion model. Development, 131: 4843-4856.
Kruse, K., Joanny, J.-F., Jülicher, F., Prost, J., and Sekimoto, K. (2004): Asters, Vortices and Rotating Spirals in Active Gels of Polar Filaments. Phys. Rev. Lett. 92, 078101.
Karsten Kruse
1998: PhD University of Frankfurt/M.
1999-2000: Post-Doc at Institut Curie, Paris
2001: Guest Scientist at Landau Institute, Moscow
2002-2004: Senior Scientist at MPI for the Physics of Complex Systems
since 2004: Group Leader at MPI for the Physics of Complex Systems
