Department Biological Physics
Frank Jülicher

for the Physics of Complex Systems
Nöthnitzer Straße 38
01187 Dresden

Tel. +49 351 871-1202
Fax. +49 351 871-1299
Curriculum Vitae
List of Publications
Research Interests

Theory of Biological Systems and Processes

The main focus of our research are theoretical approaches to understand dynamic processes in cells and tissues. Work on active cellular processes includes the study of cellular oscillations, cellular signaling and the cytoskeletal dynamics during cell division and cell motility. We furthermore study the biophysical basis of hearing. Finally, we investigate the biophysical properties and dynamics of tissues and epithelia. Based on the properties of individual cells and of cellular signaling systems, we are interested in the dynamics of developmental processes, for example wing development in the fruit fly.

Research topics include:

Active cellular processes
Cellular oscillations
Swimming of microorganisms
Cell locomotion

Physics of the cytoskeleton and of motor proteins
Active gels and fluids
Collective behaviors of motor proteins
Self-organization phenomena in the cytoskeleton

Physics of Cell Division

Tissues and developmental processes
Cellular packings in epithelia
Cellular rearrangements during growth and development
Morphogen signaling and morphogen gradient formation

Biophysics of hearing
Active mechanics of hair cells
Cochlear waves
Signal amplification by nonlinear oscillators

Research Highlights

An Active Oscillator Model Describes the Statistics of Spontaneous Otoacoustic Emissions
F. Fruth, F. Jüicher, B. Lindner
Biophys J. 107, 817 (2014)
PDF (1,6 MB)]

Local Increases in Mechanical Tension Shape Compartment Boundaries by
Biasing Cell Intercalations
D. Umetsu, B. Aigouy, M. Aliee, S. Sui, S. Eaton, F. Jülicher and C. Dahmann
Curr. Biol. 24, 1798 (2014)
PDF (3,9 MB)]

Active Phase and Amplitude Fluctuations of Flagellar Beating
R. Ma, G. S. Klindt, I. H. Riedel-Kruse, F. Jülicher and B. Friedrich
Phys. Rev. Lett. 113, 048101 (2014)
PDF (1,3 MB)]

Multimotor Transport in a System of Active and inactive Kinesin-1 Motors
L. Scharrel, R. Ma, R. Schneider, F. Jülicher and S. Diez
Biophys. J. 107, 365 (2014)
PDF (1 MB)]

A Doppler effect in embryonic pattern formation
D. Soroldoni, D. J. Jörg, L. G. Morelli, D. L. Richmond, J. Schindelin, F. Jülicher and A. C. Oates
Science 345, 222 (2014)
PDF (623 kB)] Supplementary Material

Centrosomes are Autocatalytic Droplets of Pericentriolar Material Organized by Centrioles

Centrosomes are located at the poles of mitotic spindles during cell division. They assemble around centrioles and can occur in different sizes. We propose that centrosome properties can be understood as a liquid like phase that assembles by an autiocatalytic reaction. The centrioles are active nucleators of centrosome assembly by starting the autocatalyic process by their catalytic activity. Our theory can quantitatively account for the observed assembly dynamics of centrosomes in normal and perturbed conditions.

D. Zwicker, M. Decker, S. Jaensch, A. A. Hyman and F. Jülicher
Proc. Natl. Acad. Sci. USA 111, E2636 (2014)
PDF (1,2 MB)]

Active Elastic Thin Shell Theory for Cellular Deformations

Cell shape is governed by the mechanics of the action cytoskeletion together with cell- cell adhesion. The actin cytoskeleton forms athin layer near the cell membraje called cell cortex. The cell cortex is an active material in which contractile stresses are generated by motor molecules. At short times the cortex is an elastic solid which at longer times exhibits viscous material properties. We develop a theory of active and elastic thin shells in order to calculate shapes of cells at short times after forced detachment of cell-cell adhesion.

H. Berthoumieux, J.-L. Maître, C.-P. Heisenberg, E. K. Paluch, F. Jülicher and G. Salbreux
New J. Phys. 16 065005 (2014)
PDF (950 kB)]

Motor Regulation Results in Distal Forces that Bend Partially Disintegrated Chlamydomonas Axonemes
into Circular Arcs

We investigate the mechanics of microtubule doublets interacting with dynein motors that can lead to circular configurations of filaments. We show that these shapes can be understood as the consquence of a dependence of the motor detachmenht rate by forces acting normal to filaments. This mechanism of motor regulation could have an important role in beating cilia such as those of swimming algea.

V. Mukundan, P. Sartori, V. F. Geyer, F. Jülicher and J. Howard
Biophys J., 106, 2434 (2014)
PDF (1 MB)]

Pulsatory Patterns in Active Fluids

The regulation of active stresses by diffusing regulatory molecules provides a simple example for mechano-chemical pattern formation. In such systems, flows are generated by gradients of active stresses which lead to the transport of regulators. The regulators themselves organize the profiles of active stress. We show that two diffusing regulators, one which upregulates and one which downregulates stress can lead to oscillating spatial patterns and waves.

K. V. Kumar, J. S. Bois, F. Jülicher and S. W. Grill
Phys. Rev. Lett. 112, 208101 (2014)
PDF (721 kB]

Transduction Channels' Gating can Control Friction on Vibrating Hair-Cell Bundles in the Ear

Hair bundles are the sensory organelles of auditory hair cells. We study the mechanical response of hair bundles to mechanical stimuli of different velocity. We show that the hair bundle exhibits a friction that is due to dissipation associated with the opening and closing of mechanosensitive ion channels. This channel friction can be larger than the friction due to motion in the viscous environment of the hair bundle.

V. Bormuth, J. Barral, J.-F. Joanny, F. Jülicher and P. Martin
Proc. Natl. Acad. Sci. USA, 111, 7185 (2014)
PDF (1,1 MB)]

Synchronization Dynamics in the Presence of Coupling Delays and Phase Shifts

We study the synchronization of dynamic oscillators in spatially extended systems. Oscillatiors are coupled to their neighbors with a time delay. We show that for sufficiently large time delay long wavelength modes can relax faster than certain short wavelength modes.

D. J. Jörg, L. G. Morelli, S. Ares and F. Jülicher
Phys. Rev. Lett. 112, 174101 (2014)
PDF (328 kB)]

Growth Control by a Moving Morphogen Gradient during Drosophila Eye Development

We study the spatial profile of cell division in the developing eye of the fly. We show that the observed pattern of tissue growth can be understood as the result of a growth control mechanism mediated by a moving morphogen profile. Our work shows that the very different proliferation patterns in the wing an the eye can be understood by a common simple principle. Cell growth and division is stimulated by the relative rate of increase of a morphogen induced signal.

O. Wartlick, F. Jülicher and M. Gonzales-Gaitan
Development. 141 1884 (2014)
PDF (4,8 MB)]

Wnt-regulated Dynamics of Positional Information in Zebrafish Somitogenesis

All vertebrate animals generate the segmented body plan and the precursors of vertebra by a dynamic oscillatory process that involves genetic wave patterns. We study the influence of Wnt signaling on the dynamics of the wavefront. We show that the segment size can be varied by varying the speed of the wave front while leaving the clock period unchanged.

L. Bajard, L. G. Morelli, S. Ares, J. Pécréaux, F. Jülicher and A. C. Oates
Development. 141 1381 (2014)
PDF (5,7 MB)]

Mechanically Driven Interface Propagation in Biological Tissues

We discuss the competition of two tissues with different homeostatic pressure in a continuum theory. We show that a tissue with larger homeostatic pressure invades the second tissue by a propagating interface and calculate the propagation velocity. This is a generalization of the Fisher-Kolmogorov wave taking in to account stress distributions and mechanics. Interestingly, we find both pulled and pushed fronts as a function of parameter values.

J. Ranft, M. Aliee, J. Prost, F. Jülicher and J.-F. Joanny
New J. Phys. 16 035002 (2014)
PDF (406 kb)]

General Theory for the Mechanics of Confined Microtubule Asters

We discuss the positioning of microtubule asters in confined geometries mediated by pushing and pulling forces on the boundary. Pulling forces can lead to robust centering and off-center positioning due to asymmetric districutions of force generators. This work applies to the positioning of mitotic spindles in the cell during symmetric and asymmetric cell divisions.

R. Ma, L. Laan, M. Dogterom, N. Pavin and F. Jülicher
New J. Phys. 16 013018 (2014)
PDF (885 kb)]

Cell-body Rocking is a Dominant Mechanism for Flagellar Synchronization in a Swimming Alga

We study the mechanisms of flagellar synchronization in the green algae Chlamydomonas. Using a combination of theory and experiment, we show that cell body rocking generated by nonsynchronous beats effectively produces an interaction between the two flagella that drives their synchronization.

V. F. Geyer, F. Jülicher, J. Howard, and B. M. Friedrich
Proc. Natl. Acad. Sci. USA, 110, 18058 (2013)
PDF (1,3 MB)]

Spatial Organization of the Cell Cytoplasm by Position-Dependent Phase Separation

The cell cytoplasm can undergo phase separation leading to the coexistence of drop-like objects with the remaining cytoplasm. Such phase separation generates droplets which concentrate certain components and provide specific chemical environments. We show how such phase separation can be used to segregate components in the cell cytoplams using a gradient of a regulator of phase separation. Such segregation plays an important role during asymmetric cell division. Cellular components can be distributed unequally to the two daughter cells.

C. F. Lee, C. P. Brangwynne, J. Gharakhani, A. A. Hyman and F. Jülicher
Phys. Rev. Lett. 111, 088101 (2013)
PDF (1,6 MB)]

XMAP215 Activity Sets Spindle Length by Controlling the Total Mass of Spindle Microtubules

During cell division, a bipolar spindle assembles from a large numbers of dynamic microtubules. We show that length of meiotic spindles, which is much bigger than the average microtubule length is set by mass balance via localized microtubule nucleation and global disassembly. We show that perturbing microtubule growth rate using mutants of microtubule growth promotor. The spindle length is proportional to microtubule growth rate which can be understood by our theory.

S. B. Reber, J. Baumgart, P. O. Widlund, A. Pozniakovsky, J. Howard, A. A. Hyman and F. Jülicher
Nature Cell Biol. 15, 1116 (2013)
PDF (4,6 MB)]

Active Chiral Processes in Thin Films

Active fluids exhibit unconventional behaviors such as the generation of spontaneous movements and flows, driven e.g. by the action of molecular motors in cells. The interactions between motors and filaments can amplify chiral asymmetries of helical filaments and lead to relative rotations and chiral flows. Active chiral processes are most striking near surfaces. We develop a thin film theory of chiral active processes which could be relevant for the emergence of chiral flows in the actin cytoskeleton in cells.

S. Fürthauer, M. Strempel, S. W. Grill and F. Jülicher
Phys. Rev. Lett. 110, 048103 (2013)
[PDF (340 kB)]

Highlights 2012
Highlights 2011
Highlights 2010
Highlights 2009
Highlights 2008
Highlights 2007
The European Physical Journal E
Last updated: 28 August 2014