Detailed Programme - 30/05/18

10:30 Arrival and coffee

11:00 Andrew Goryachev (University of Edinbrugh)

Title: Symmetry breaking in biological cells: Molecular mechanisms of intracellular pattern formation

Abstract: Pattern formation in biological systems continues to captivate the attention of biologists, physicists, and mathematicians alike many decades after the seminal works by Turing, Prigogine, Murray and others. In fact, I claim that the area of biological pattern formation becomes only more and more exciting. The better are the microscopes that biologists develop, the more spectacular phenomena predicted by the nonlinear dynamical systems theory we can observe in live cells. I will present an overview of the work we have done over the past decade trying to understand the biophysical mechanisms of intracellular pattern formation and morphogenesis.

12:00 Jacob Halatek (LMU Munich)

Title: Rethinking pattern formation in reaction–diffusion systems

Abstract: The present theoretical framework for the analysis of pattern formation in complex systems is mostly limited to the vicinity of fixed (global) equilibria. Here we present a new theoretical approach to characterize dynamical states arbitrarily far from (global) equilibrium. We show that reaction–diffusion systems that are driven by locally mass-conserving interactions can be understood in terms of local equilibria of diffusively coupled compartments. Diffusive coupling generically induces lateral redistribution of the globally conserved quantities, and the variable local amounts of these quantities determine the local equilibria in each compartment. We find that, even far from global equilibrium, the system is well characterized by its moving local equilibria. We apply this framework to in vitro Min protein pattern formation, a paradigmatic model for biological pattern formation. Within our framework we can predict and explain transitions between chemical turbulence and order arbitrarily far from global equilibrium. Our results reveal conceptually new principles of self-organized pattern formation that may well govern diverse dynamical systems.

12:30 Lunch

14:00 Stan Maree (John Innes Centre)

Title: Coupling reaction-diffusion to cell shape to unravel emergent cell signalling behaviour

Abstract: Pattern formation through reaction-diffusion of proteins is core to establishing functionally distinct domains within cells. In fact, cells are able to be in either a “rest state”, in which such proteins are distributed homogeneously along its interior, or in a “polarised” state, in which clear domains are established. This phenomenon of polarisation also allows cells to change shape. Animal cell motility is driven by the formation of such domains, while plant cells, encased in a rigid cellulose cell wall, use them for cell shape changes and polar transmission of signals. Molecular studies reveal that even though plants and animals diverged 1.6 billion years ago, they still share a similar core machinery required for cell shape changes. A fascinating similarity between animal and plant cells with respect to the organisation of cytoskeletal elements in the regions of active protrusive growth and cell wall extension (the leading edges), is paralleled by a striking conserved molecular mechanism responsible for the creation and organisation of these leading edges. To unravel and understand the interplay and feedbacks which brings about cell motility, we have previously developed a multiscale model of a motile keratocyte, describing how the reaction-diffusion module can be biophysically coupled to the cells' deformation. We contrast this to the cell shape changes that occur outcome of feedbacks between intracellular reaction-diffusion patterning, cell shape dynamics and external signals.

15:00 Claire Grierson(University of Bristol)


15:30 Tea

16:00 Svitlana Braichenko (University of Southampton)

Title: The spatial arrangements of stochastic Ca2+ signals triggered by IP3 release

Abstract: Clusters of IP3 receptor channels in the membranes of the endoplasmic reticulum (ER) of many non-excitable cells release calcium ions in a cooperative manner giving rise to dynamical patterns such as Ca2+ puffs, waves and oscillations that occur on various spatial and temporal scales. We introduce a stochastic reaction-diffusion model of randomly distributed IP3 receptors using a principled reduction of a detailed Markov chain description of individual channels. Our model reveals how the crucial characteristic of cell regulation such as inter-wave intervals (IWI) depends on the IP3 loads. Furthermore, by performing a correlation analysis of the [Ca2+] at the neighbouring clusters, we obtain the principal characteristics of the membrane which define the possibility of Ca2+ wave initiation and propagation. Using given approach, we aim to link the local properties of IP3R channels and clusters, such as channel type or coupling between channels, with the global patterns which may emerge from these channels, e. g. spikes, waves or oscillations.

16:30 Hayley Mills (University of Nottingham)

Title: Compartmentalised signalling and signalling microdomains of intracellular calcium

Abstract: TBA

17:00 Close