ERC FUNDED PROJECTS

Cell volume regulation is crucial for any living cell because changes in volume determine the metabolic activity through e.g. changes in ionic strength, pH, macromolecular crowding and membrane tension. These physical chemical parameters influence interaction rates and affinities of biomolecules, folding rates, and fold stabilities in vivo. Understanding of the underlying volume regulatory mechanisms has immediate application in biotechnology and health, yet these factors are generally ignored in systems analyses of cellular functions. My team has uncovered a number of mechanisms and insights of cell volume regulation. The next step forward is to elucidate how the components of a cell volume regulatory circuit work together and control the physicochemical conditions of the cell. I propose construction of a synthetic cell in which an osmoregulatory transporter and mechanosensitive channel form a minimal volume regulatory network. My group has developed the technology to reconstitute membrane proteins into lipid vesicles (synthetic cells). One of the challenges is to incorporate into the vesicles an efficient pathway for ATP production and maintain energy homeostasis while the load on the system varies. We aim to control the transmembrane flux of osmolytes, which requires elucidation of the molecular mechanism of gating of the osmoregulatory transporter. We will focus on the glycine betaine ABC importer, which is one of the most complex transporters known to date with ten distinct protein domains, transiently interacting with each other. The proposed synthetic metabolic circuit constitutes a fascinating out-of-equilibrium system, allowing us to understand cell volume regulatory mechanisms in a context and at a level of complexity minimally needed for life. Analysis of this circuit will address many outstanding questions and eventually allow us to design more sophisticated vesicular systems with applications, for example as compartmentalized reaction networks.

2 247 231 €

Start date: 2015-07-01, End date: 2020-06-30

In an era of rapid climate change there is a pressing need to understand whether and how organisms are able to adapt to novel environments. Such understanding is hampered by a major divide in the life sciences. Disciplines like systems biology or neurobiology make rapid progress in unravelling the mechanisms underlying the responses of organisms to their environment, but this knowledge is insufficiently integrated in eco-evolutionary theory. Current eco-evolutionary models focus on the response patterns themselves, largely neglecting the structures and mechanisms producing these patterns. Here I propose a new, mechanism-oriented framework that views the architecture of adaptation, rather than the resulting responses, as the primary target of natural selection. I am convinced that this change in perspective will yield fundamentally new insights, necessitating the re-evaluation of many seemingly well-established eco-evolutionary principles. My aim is to develop a comprehensive theory of the eco-evolutionary causes and consequences of the architecture underlying adaptive responses. In three parallel lines of investigation, I will study how architecture is shaped by selection, how evolved response strategies reflect the underlying architecture, and how these responses affect the eco-evolutionary dynamics and the capacity to adapt to novel conditions. All three lines have the potential of making ground-breaking contributions to eco-evolutionary theory, including: the specification of evolutionary tipping points; resolving the puzzle that real organisms evolve much faster than predicted by current theory; a new and general explanation for the evolutionary emergence of individual variation; and a framework for studying the evolution of learning and other general-purpose mechanisms. By making use of concepts from information theory and artificial intelligence, the project will also introduce various methodological innovations.

2 500 000 €

Start date: 2018-12-01, End date: 2023-11-30

For over a century it was believed that ammonium could only be oxidized by microbes in the presence of oxygen. The possibility of anaerobic ammonium oxidation (anammox) was considered impossible. However, about 10 years ago the microbes responsible for the anammox reaction were discovered in a wastewater plant. This was followed by the identification of the responsible bacteria. Recently, the widespread environmental occurrence of the anammox bacteria was demonstrated leading to the realization that anammox bacteria may play a major role in biological nitrogen cycling. The anammox bacteria are unique microbes with many unusual properties. These include the biological turn-over of hydrazine, a well known rocket fuel, the biological synthesis of ladderane lipids, and the presence of a prokaryotic organelle in the cytoplasma of anammox bacteria. The aim of this project is to obtain a fundamental understanding of the metabolism and ecological importance of the anammox bacteria. Such understanding contributes directly to our environment and economy because the anammox bacteria form a new opportunity for nitrogen removal from wastewater, cheaper, with lower carbon dioxide emissions than existing technology. Scientifically the results will contribute to the understanding how hydrazine and dinitrogen gas are made by the anammox bacteria. The research will show which gene products are responsible for the anammox reaction, and how their expression is regulated. Furthermore, the experiments proposed will show if the prokaryotic organelle in anammox bacteria is involved in energy generation. Together the environmental and metabolic data will help to understand why anammox bacteria are so successful in the biogeochemical nitrogen cycle and thus shape our planets atmosphere. The different research lines will employ state of the art microbial and molecular methods to unravel the exceptional properties of these highly unusual and important anammox bacteria.

2 500 000 €

Start date: 2009-01-01, End date: 2013-12-31

Life on earth is sustained by the process that converts sunlight energy into chemical energy: photosynthesis. This process is operating near the boundary between life and death: if the absorbed energy exceeds the capacity of the metabolic reactions, it can result in photo-oxidation events that can cause the death of the organism. Over-excitation is happening quite often: oxygenic organisms are exposed to (drastic) changes in environmental conditions (light intensity, light quality and temperature), which influence the physical (light-harvesting) and chemical (enzymatic reactions) parts of the photosynthetic process to a different extent, leading to severe imbalances. However, daily experience tells us that plants are able to deal with most of these situations, surviving and happily growing. How do they manage? The photosynthetic membrane is highly flexible and it is able to change its supramolecular organization and composition and even the function of some of its components on a time scale as fast as a few seconds, thereby regulating the light-harvesting capacity. However, the structural/functional changes in the membrane are far from being fully characterized and the molecular mechanisms of their regulation are far from being understood. This is due to the fact that all these mechanisms require the simultaneous presence of various factors and thus the system should be analyzed at a high level of complexity; however, to obtain molecular details of a very complex system as the thylakoid membrane in action has not been possible so far. Over the last years we have developed and optimized a range of methods that now allow us to take up this challenge. This involves a high level of integration of biological and physical approaches, ranging from plant transformation and in vivo knock out of individual pigments to ultrafast-spectroscopy in a mix that is rather unique for my laboratory and will allow us to unravel the photoprotective mechanisms in algae and plants.

1 696 961 €

Start date: 2011-12-01, End date: 2017-11-30