Project acronym ACE-OF-SPACE
Project Analysis, control, and engineering of spatiotemporal pattern formation
Researcher (PI) Patrick MÜLLER
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Consolidator Grant (CoG), LS3, ERC-2019-COG
Summary A central problem in developmental biology is to understand how tissues are patterned in time and space - how do identical cells differentiate to form the adult body plan? Patterns often arise from prior asymmetries in developing embryos, but there is also increasing evidence for self-organizing mechanisms that can break the symmetry of an initially homogeneous cell population. These patterning processes are mediated by a small number of signaling molecules, including the TGF-β superfamily members BMP and Nodal. While we have begun to analyze how biophysical properties such as signal diffusion and stability contribute to axis formation and tissue allocation during vertebrate embryogenesis, three key questions remain. First, how does signaling cross-talk control robust patterning in developing tissues? Opposing sources of Nodal and BMP are sufficient to produce secondary zebrafish axes, but it is unclear how the signals interact to orchestrate this mysterious process. Second, how do signaling systems self-organize to pattern tissues in the absence of prior asymmetries? Recent evidence indicates that axis formation in mammalian embryos is independent of maternal and extra-embryonic tissues, but the mechanism underlying this self-organized patterning is unknown. Third, what are the minimal requirements to engineer synthetic self-organizing systems? Our theoretical analyses suggest that self-organizing reaction-diffusion systems are more common and robust than previously thought, but this has so far not been experimentally demonstrated. We will address these questions in zebrafish embryos, mouse embryonic stem cells, and bacterial colonies using a combination of quantitative imaging, optogenetics, mathematical modeling, and synthetic biology. In addition to providing insights into signaling and development, this high-risk/high-gain approach opens exciting new strategies for tissue engineering by providing asymmetric or temporally regulated signaling in organ precursors.
Summary
A central problem in developmental biology is to understand how tissues are patterned in time and space - how do identical cells differentiate to form the adult body plan? Patterns often arise from prior asymmetries in developing embryos, but there is also increasing evidence for self-organizing mechanisms that can break the symmetry of an initially homogeneous cell population. These patterning processes are mediated by a small number of signaling molecules, including the TGF-β superfamily members BMP and Nodal. While we have begun to analyze how biophysical properties such as signal diffusion and stability contribute to axis formation and tissue allocation during vertebrate embryogenesis, three key questions remain. First, how does signaling cross-talk control robust patterning in developing tissues? Opposing sources of Nodal and BMP are sufficient to produce secondary zebrafish axes, but it is unclear how the signals interact to orchestrate this mysterious process. Second, how do signaling systems self-organize to pattern tissues in the absence of prior asymmetries? Recent evidence indicates that axis formation in mammalian embryos is independent of maternal and extra-embryonic tissues, but the mechanism underlying this self-organized patterning is unknown. Third, what are the minimal requirements to engineer synthetic self-organizing systems? Our theoretical analyses suggest that self-organizing reaction-diffusion systems are more common and robust than previously thought, but this has so far not been experimentally demonstrated. We will address these questions in zebrafish embryos, mouse embryonic stem cells, and bacterial colonies using a combination of quantitative imaging, optogenetics, mathematical modeling, and synthetic biology. In addition to providing insights into signaling and development, this high-risk/high-gain approach opens exciting new strategies for tissue engineering by providing asymmetric or temporally regulated signaling in organ precursors.
Max ERC Funding
1 997 750 €
Duration
Start date: 2020-07-01, End date: 2025-06-30
Project acronym ACTMECH
Project Emergent Active Mechanical Behaviour of the Actomyosin Cell Cortex
Researcher (PI) Stephan Wolfgang Grill
Host Institution (HI) TECHNISCHE UNIVERSITAET DRESDEN
Call Details Starting Grant (StG), LS3, ERC-2011-StG_20101109
Summary The cell cortex is a highly dynamic layer of crosslinked actin filaments and myosin molecular motors beneath the cell membrane. It plays a central role in large scale rearrangements that occur inside cells. Many molecular mechanisms contribute to cortex structure and dynamics. However, cell scale physical properties of the cortex are difficult to grasp. This is problematic because for large scale rearrangements inside a cell, such as coherent flow of the cell cortex, it is the cell scale emergent properties that are important for the realization of such events. I will investigate how the actomyosin cytoskeleton behaves at a coarse grained and cellular scale, and will study how this emergent active behaviour is influenced by molecular mechanisms. We will study the cell cortex in the one cell stage C. elegans embryo, which undergoes large scale cortical flow during polarization and cytokinesis. We will combine theory and experiment. We will characterize cortex structure and dynamics with biophysical techniques such as cortical laser ablation and quantitative photobleaching experiments. We will develop and employ novel theoretical approaches to describe the cell scale mechanical behaviour in terms of an active complex fluid. We will utilize genetic approaches to understand how these emergent mechanical properties are influenced by molecular activities. A central goal is to arrive at a coarse grained description of the cortex that can predict future dynamic behaviour from the past structure, which is conceptually similar to how weather forecasting is accomplished. To date, systematic approaches to link molecular scale physical mechanisms to those on cellular scales are missing. This work will open new opportunities for cell biological and cell biophysical research, by providing a methodological approach for bridging scales, for studying emergent and large-scale active mechanical behaviours and linking them to molecular mechanisms.
Summary
The cell cortex is a highly dynamic layer of crosslinked actin filaments and myosin molecular motors beneath the cell membrane. It plays a central role in large scale rearrangements that occur inside cells. Many molecular mechanisms contribute to cortex structure and dynamics. However, cell scale physical properties of the cortex are difficult to grasp. This is problematic because for large scale rearrangements inside a cell, such as coherent flow of the cell cortex, it is the cell scale emergent properties that are important for the realization of such events. I will investigate how the actomyosin cytoskeleton behaves at a coarse grained and cellular scale, and will study how this emergent active behaviour is influenced by molecular mechanisms. We will study the cell cortex in the one cell stage C. elegans embryo, which undergoes large scale cortical flow during polarization and cytokinesis. We will combine theory and experiment. We will characterize cortex structure and dynamics with biophysical techniques such as cortical laser ablation and quantitative photobleaching experiments. We will develop and employ novel theoretical approaches to describe the cell scale mechanical behaviour in terms of an active complex fluid. We will utilize genetic approaches to understand how these emergent mechanical properties are influenced by molecular activities. A central goal is to arrive at a coarse grained description of the cortex that can predict future dynamic behaviour from the past structure, which is conceptually similar to how weather forecasting is accomplished. To date, systematic approaches to link molecular scale physical mechanisms to those on cellular scales are missing. This work will open new opportunities for cell biological and cell biophysical research, by providing a methodological approach for bridging scales, for studying emergent and large-scale active mechanical behaviours and linking them to molecular mechanisms.
Max ERC Funding
1 500 000 €
Duration
Start date: 2011-12-01, End date: 2017-08-31
Project acronym AngioBone
Project Angiogenic growth, specialization, ageing and regeneration
of bone vessels
Researcher (PI) Ralf Heinrich Adams
Host Institution (HI) WESTFAELISCHE WILHELMS-UNIVERSITAET MUENSTER
Call Details Advanced Grant (AdG), LS3, ERC-2013-ADG
Summary The skeleton and the sinusoidal vasculature form a functional unit with great relevance in health, regeneration, and disease. Currently, fundamental aspects of sinusoidal vessel growth, specialization, arteriovenous organization and the consequences for tissue perfusion, or the changes occurring during ageing remain unknown. Our preliminary data indicate that key principles of bone vascularization and the role of molecular regulators are highly distinct from other organs. I therefore propose to use powerful combination of mouse genetics, fate mapping, transcriptional profiling, computational biology, confocal and two-photon microscopy, micro-CT and PET imaging, biochemistry and cell biology to characterize the growth, differentiation, dynamics, and ageing of the bone vasculature. In addition to established angiogenic pathways, the role of highly promising novel candidate regulators will be investigated in endothelial cells and perivascular osteoprogenitors with sophisticated inducible and cell type-specific genetic methods in the mouse. Complementing these powerful in vivo approaches, 3D co-cultures generated by cell printing technologies will provide insight into the communication between different cell types. The dynamics of sinusoidal vessel growth and regeneration will be monitored by two-photon imaging in the skull. Finally, I will explore the architectural, cellular and molecular changes and the role of capillary endothelial subpopulations in the sinusoidal vasculature of ageing and osteoporotic mice.
Technological advancements, such as new transgenic strains, mutant models or cell printing approaches, are important aspects of this proposal. AngioBone will provide a first conceptual framework for normal and deregulated function of the bone sinusoidal vasculature. It will also break new ground by analyzing the role of blood vessels in ageing and identifying novel strategies for tissue engineering and, potentially, the prevention/treatment of osteoporosis.
Summary
The skeleton and the sinusoidal vasculature form a functional unit with great relevance in health, regeneration, and disease. Currently, fundamental aspects of sinusoidal vessel growth, specialization, arteriovenous organization and the consequences for tissue perfusion, or the changes occurring during ageing remain unknown. Our preliminary data indicate that key principles of bone vascularization and the role of molecular regulators are highly distinct from other organs. I therefore propose to use powerful combination of mouse genetics, fate mapping, transcriptional profiling, computational biology, confocal and two-photon microscopy, micro-CT and PET imaging, biochemistry and cell biology to characterize the growth, differentiation, dynamics, and ageing of the bone vasculature. In addition to established angiogenic pathways, the role of highly promising novel candidate regulators will be investigated in endothelial cells and perivascular osteoprogenitors with sophisticated inducible and cell type-specific genetic methods in the mouse. Complementing these powerful in vivo approaches, 3D co-cultures generated by cell printing technologies will provide insight into the communication between different cell types. The dynamics of sinusoidal vessel growth and regeneration will be monitored by two-photon imaging in the skull. Finally, I will explore the architectural, cellular and molecular changes and the role of capillary endothelial subpopulations in the sinusoidal vasculature of ageing and osteoporotic mice.
Technological advancements, such as new transgenic strains, mutant models or cell printing approaches, are important aspects of this proposal. AngioBone will provide a first conceptual framework for normal and deregulated function of the bone sinusoidal vasculature. It will also break new ground by analyzing the role of blood vessels in ageing and identifying novel strategies for tissue engineering and, potentially, the prevention/treatment of osteoporosis.
Max ERC Funding
2 478 750 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym APOQUANT
Project The quantitative Bcl-2 interactome in apoptosis: decoding how cancer cells escape death
Researcher (PI) Ana Jesús García Sáez
Host Institution (HI) EBERHARD KARLS UNIVERSITAET TUEBINGEN
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary The proteins of the Bcl-2 family function as key regulators of apoptosis by controlling the permeabilization of the mitochondrial outer membrane. They form an intricate, fine-tuned interaction network which is altered in cancer cells to avoid cell death. Currently, we do not understand how signaling within this network, which combines events in cytosol and membranes, is orchestrated to decide the cell fate. The main goal of this proposal is to unravel how apoptosis signaling is integrated by the Bcl-2 network by determining the quantitative Bcl-2 interactome and building with it a mathematical model that identifies which interactions determine the overall outcome. To this aim, we have established a reconstituted system for the quantification of the interactions between Bcl-2 proteins not only in solution but also in membranes at the single molecule level by fluorescence correlation spectroscopy (FCS).
(1) This project aims to quantify the relative affinities between an reconstituted Bcl-2 network by FCS.
(2) This will be combined with quantitative studies in living cells, which include the signaling pathway in its entirety. To this aim, we will develop new FCS methods for mitochondria.
(3) The structural and dynamic aspects of the Bcl-2 network will be studied by super resolution and live cell microscopy.
(4) The acquired knowledge will be used to build a mathematical model that uncovers how the multiple interactions within the Bcl-2 network are integrated and identifies critical steps in apoptosis regulation.
These studies are expected to broaden the general knowledge about the design principles of cellular signaling as well as how cancer cells alter the Bcl-2 network to escape cell death. This systems analysis will allow us to predict which perturbations in the Bcl-2 network of cancer cells can switch signaling towards cell death. Ultimately it could be translated into clinical applications for anticancer therapy.
Summary
The proteins of the Bcl-2 family function as key regulators of apoptosis by controlling the permeabilization of the mitochondrial outer membrane. They form an intricate, fine-tuned interaction network which is altered in cancer cells to avoid cell death. Currently, we do not understand how signaling within this network, which combines events in cytosol and membranes, is orchestrated to decide the cell fate. The main goal of this proposal is to unravel how apoptosis signaling is integrated by the Bcl-2 network by determining the quantitative Bcl-2 interactome and building with it a mathematical model that identifies which interactions determine the overall outcome. To this aim, we have established a reconstituted system for the quantification of the interactions between Bcl-2 proteins not only in solution but also in membranes at the single molecule level by fluorescence correlation spectroscopy (FCS).
(1) This project aims to quantify the relative affinities between an reconstituted Bcl-2 network by FCS.
(2) This will be combined with quantitative studies in living cells, which include the signaling pathway in its entirety. To this aim, we will develop new FCS methods for mitochondria.
(3) The structural and dynamic aspects of the Bcl-2 network will be studied by super resolution and live cell microscopy.
(4) The acquired knowledge will be used to build a mathematical model that uncovers how the multiple interactions within the Bcl-2 network are integrated and identifies critical steps in apoptosis regulation.
These studies are expected to broaden the general knowledge about the design principles of cellular signaling as well as how cancer cells alter the Bcl-2 network to escape cell death. This systems analysis will allow us to predict which perturbations in the Bcl-2 network of cancer cells can switch signaling towards cell death. Ultimately it could be translated into clinical applications for anticancer therapy.
Max ERC Funding
1 462 900 €
Duration
Start date: 2013-04-01, End date: 2019-03-31
Project acronym APOSITE
Project Apoptotic foci: composition, structure and dynamics
Researcher (PI) Ana GARCIA SAEZ
Host Institution (HI) UNIVERSITAET ZU KOELN
Call Details Consolidator Grant (CoG), LS3, ERC-2018-COG
Summary Apoptotic cell death is essential for development, immune function or tissue homeostasis, and it is often deregulated in disease. Mitochondrial outer membrane permeabilization (MOMP) is central for apoptosis execution and plays a key role in its inflammatory outcome. Knowing the architecture of the macromolecular machineries mediating MOMP is crucial for understanding their function and for the clinical use of apoptosis.
Our recent work reveals that Bax and Bak dimers form distinct line, arc and ring assemblies at specific apoptotic foci to mediate MOMP. However, the molecular structure and mechanisms controlling the spatiotemporal formation and range of action of the apoptotic foci are missing. To address this fundamental gap in our knowledge, we aim to unravel the composition, dynamics and structure of apoptotic foci and to understand how they are integrated to orchestrate function. We will reach this goal by building on our expertise in cell death and cutting-edge imaging and by developing a new analytical pipeline to:
1) Identify the composition of apoptotic foci using in situ proximity-dependent labeling and extraction of near-native Bax/Bak membrane complexes coupled to mass spectrometry.
2) Define their contribution to apoptosis and its immunogenicity and establish their assembly dynamics to correlate it with apoptosis progression by live cell imaging.
3) Determine the stoichiometry and structural organization of the apoptotic foci by combining single molecule fluorescence and advanced electron microscopies.
This multidisciplinary approach offers high chances to solve the long-standing question of how Bax and Bak mediate MOMP. APOSITE will provide textbook knowledge of the mitochondrial contribution to cell death and inflammation. The implementation of this new analytical framework will open novel research avenues in membrane and organelle biology. Ultimately, understanding of Bax and Bak structure/function will help develop apoptosis modulators for medicine.
Summary
Apoptotic cell death is essential for development, immune function or tissue homeostasis, and it is often deregulated in disease. Mitochondrial outer membrane permeabilization (MOMP) is central for apoptosis execution and plays a key role in its inflammatory outcome. Knowing the architecture of the macromolecular machineries mediating MOMP is crucial for understanding their function and for the clinical use of apoptosis.
Our recent work reveals that Bax and Bak dimers form distinct line, arc and ring assemblies at specific apoptotic foci to mediate MOMP. However, the molecular structure and mechanisms controlling the spatiotemporal formation and range of action of the apoptotic foci are missing. To address this fundamental gap in our knowledge, we aim to unravel the composition, dynamics and structure of apoptotic foci and to understand how they are integrated to orchestrate function. We will reach this goal by building on our expertise in cell death and cutting-edge imaging and by developing a new analytical pipeline to:
1) Identify the composition of apoptotic foci using in situ proximity-dependent labeling and extraction of near-native Bax/Bak membrane complexes coupled to mass spectrometry.
2) Define their contribution to apoptosis and its immunogenicity and establish their assembly dynamics to correlate it with apoptosis progression by live cell imaging.
3) Determine the stoichiometry and structural organization of the apoptotic foci by combining single molecule fluorescence and advanced electron microscopies.
This multidisciplinary approach offers high chances to solve the long-standing question of how Bax and Bak mediate MOMP. APOSITE will provide textbook knowledge of the mitochondrial contribution to cell death and inflammation. The implementation of this new analytical framework will open novel research avenues in membrane and organelle biology. Ultimately, understanding of Bax and Bak structure/function will help develop apoptosis modulators for medicine.
Max ERC Funding
2 000 000 €
Duration
Start date: 2019-04-01, End date: 2024-03-31
Project acronym ASYMMEM
Project Lipid asymmetry: a cellular battery?
Researcher (PI) André NADLER
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Starting Grant (StG), LS3, ERC-2017-STG
Summary It is a basic textbook notion that the plasma membranes of virtually all organisms display an asymmetric lipid distribution between inner and outer leaflets far removed from thermodynamic equilibrium. As a fundamental biological principle, lipid asymmetry has been linked to numerous cellular processes. However, a clear mechanistic justification for the continued existence of lipid asymmetry throughout evolution has yet to be established. We propose here that lipid asymmetry serves as a store of potential energy that is used to fuel energy-intense membrane remodelling and signalling events for instance during membrane fusion and fission. This implies that rapid, local changes of trans-membrane lipid distribution rather than a continuously maintained out-of-equilibrium situation are crucial for cellular function. Consequently, new methods for quantifying the kinetics of lipid trans-bilayer movement are required, as traditional approaches are mostly suited for analysing quasi-steady-state conditions. Addressing this need, we will develop and employ novel photochemical lipid probes and lipid biosensors to quantify localized trans-bilayer lipid movement. We will use these tools for identifying yet unknown protein components of the lipid asymmetry regulating machinery and analyse their function with regard to membrane dynamics and signalling in cell motility. Focussing on cell motility enables targeted chemical and genetic perturbations while monitoring lipid dynamics on timescales and in membrane structures that are well suited for light microscopy. Ultimately, we aim to reconstitute lipid asymmetry as a driving force for membrane remodelling in vitro. We expect that our work will break new ground in explaining one of the least understood features of the plasma membrane and pave the way for a new, dynamic membrane model. Since the plasma membrane serves as the major signalling hub, this will have impact in almost every area of the life sciences.
Summary
It is a basic textbook notion that the plasma membranes of virtually all organisms display an asymmetric lipid distribution between inner and outer leaflets far removed from thermodynamic equilibrium. As a fundamental biological principle, lipid asymmetry has been linked to numerous cellular processes. However, a clear mechanistic justification for the continued existence of lipid asymmetry throughout evolution has yet to be established. We propose here that lipid asymmetry serves as a store of potential energy that is used to fuel energy-intense membrane remodelling and signalling events for instance during membrane fusion and fission. This implies that rapid, local changes of trans-membrane lipid distribution rather than a continuously maintained out-of-equilibrium situation are crucial for cellular function. Consequently, new methods for quantifying the kinetics of lipid trans-bilayer movement are required, as traditional approaches are mostly suited for analysing quasi-steady-state conditions. Addressing this need, we will develop and employ novel photochemical lipid probes and lipid biosensors to quantify localized trans-bilayer lipid movement. We will use these tools for identifying yet unknown protein components of the lipid asymmetry regulating machinery and analyse their function with regard to membrane dynamics and signalling in cell motility. Focussing on cell motility enables targeted chemical and genetic perturbations while monitoring lipid dynamics on timescales and in membrane structures that are well suited for light microscopy. Ultimately, we aim to reconstitute lipid asymmetry as a driving force for membrane remodelling in vitro. We expect that our work will break new ground in explaining one of the least understood features of the plasma membrane and pave the way for a new, dynamic membrane model. Since the plasma membrane serves as the major signalling hub, this will have impact in almost every area of the life sciences.
Max ERC Funding
1 500 000 €
Duration
Start date: 2018-01-01, End date: 2022-12-31
Project acronym BacForce
Project Quantifying minute forces: How mechanoregulation determines the behavior of pathogenic bacteria
Researcher (PI) Benedikt SABASS
Host Institution (HI) LUDWIG-MAXIMILIANS-UNIVERSITAET MUENCHEN
Call Details Starting Grant (StG), LS3, ERC-2019-STG
Summary Bacteria can generate mechanical forces that are important for the colonization of surfaces, formation of biofilms, and infection of host cells. This proposal addresses the fundamental question of how bacteria can control their force generation to robustly respond to chemo-mechanical cues on complex surfaces. Currently, a knowledge gap exists between the molecular regulation pathways on the one hand and the mechanical behavior on the other hand. One major impediment for understanding of how behavior is connected to control is, to date, the impossibility of studying bacterial force directly in unconstrained situations. Based on an initial study, I propose employing new methods for the unperturbed, high-resolution measurement of bacterial traction forces on wide spatiotemporal scales. Thus, the force-generation linking behavior to control can be investigated directly.
The objectives are to (A) gain access to nanoscopic mechanical phenomena through the development of cutting-edge super-resolution traction force microscopy, (B) employ the methods to characterize how Pseudomonas aeruginosa controls pilus-generated forces while responding to chemical cues, and (C) establish how surface rigidity affects force generation by P. aeruginosa during biofilm formation. In an interdisciplinary approach, I will combine traction measurements with genetic perturbations, molecule labeling, and computer simulations to produce functional models of the mechanocontrol strategies.
Altogether, I will establish a novel technique, opening up the possibility of studying nanoscopic force generation in many types of cells. Through these advances, I will characterize a set of mechanoregulation strategies in P. aeruginosa that are paradigmatic for diverse Gram-negative pathogens employing the same type of pili. Broadly, I expect that the studied bacterial control strategies have a generic, minimal nature and can appear as basic motives throughout development, homeostasis, and disease.
Summary
Bacteria can generate mechanical forces that are important for the colonization of surfaces, formation of biofilms, and infection of host cells. This proposal addresses the fundamental question of how bacteria can control their force generation to robustly respond to chemo-mechanical cues on complex surfaces. Currently, a knowledge gap exists between the molecular regulation pathways on the one hand and the mechanical behavior on the other hand. One major impediment for understanding of how behavior is connected to control is, to date, the impossibility of studying bacterial force directly in unconstrained situations. Based on an initial study, I propose employing new methods for the unperturbed, high-resolution measurement of bacterial traction forces on wide spatiotemporal scales. Thus, the force-generation linking behavior to control can be investigated directly.
The objectives are to (A) gain access to nanoscopic mechanical phenomena through the development of cutting-edge super-resolution traction force microscopy, (B) employ the methods to characterize how Pseudomonas aeruginosa controls pilus-generated forces while responding to chemical cues, and (C) establish how surface rigidity affects force generation by P. aeruginosa during biofilm formation. In an interdisciplinary approach, I will combine traction measurements with genetic perturbations, molecule labeling, and computer simulations to produce functional models of the mechanocontrol strategies.
Altogether, I will establish a novel technique, opening up the possibility of studying nanoscopic force generation in many types of cells. Through these advances, I will characterize a set of mechanoregulation strategies in P. aeruginosa that are paradigmatic for diverse Gram-negative pathogens employing the same type of pili. Broadly, I expect that the studied bacterial control strategies have a generic, minimal nature and can appear as basic motives throughout development, homeostasis, and disease.
Max ERC Funding
1 498 864 €
Duration
Start date: 2020-08-01, End date: 2025-07-31
Project acronym bi-BLOCK
Project Building and bypassing plant polyspermy blocks
Researcher (PI) Rita Helene Groß-Hardt
Host Institution (HI) UNIVERSITAET BREMEN
Call Details Consolidator Grant (CoG), LS3, ERC-2014-CoG
Summary The ultimate goal for the survival of all species on earth is to reproduce. This uncompromising principle has triggered the evolution of numerous adaptations. One strategy commonly employed by sexually reproducing eukaryotes is the production of tremendous amounts of sperm to maximize the likelihood of an egg becoming fertilised. High sperm to egg ratios are, however, associated with an increased risk of supernumerary sperm fusion. This so-called polyspermy is lethal in many organisms. Accordingly, eukaryotes have evolved polyspermy barriers, which are implemented at different levels in the reproductive process. Flowering plants tightly control the number of sperm-transporting pollen tubes approaching a single ovule by a so-called pollen tube block. We have recently shown that the pollen tube block is relaxed in ethylene hyposensitive plants. Capitalizing on these results, this project aims at identifying and characterising the molecular mechanisms underlying plant polyspermy barriers.
Summary
The ultimate goal for the survival of all species on earth is to reproduce. This uncompromising principle has triggered the evolution of numerous adaptations. One strategy commonly employed by sexually reproducing eukaryotes is the production of tremendous amounts of sperm to maximize the likelihood of an egg becoming fertilised. High sperm to egg ratios are, however, associated with an increased risk of supernumerary sperm fusion. This so-called polyspermy is lethal in many organisms. Accordingly, eukaryotes have evolved polyspermy barriers, which are implemented at different levels in the reproductive process. Flowering plants tightly control the number of sperm-transporting pollen tubes approaching a single ovule by a so-called pollen tube block. We have recently shown that the pollen tube block is relaxed in ethylene hyposensitive plants. Capitalizing on these results, this project aims at identifying and characterising the molecular mechanisms underlying plant polyspermy barriers.
Max ERC Funding
1 910 769 €
Duration
Start date: 2015-09-01, End date: 2021-03-31
Project acronym BRAINEVODEVO
Project A Neuron Type Atlas of the Annelid Brain: Development and Evolution of Chemosensory-Motor Circuits
Researcher (PI) Detlev Arendt
Host Institution (HI) EUROPEAN MOLECULAR BIOLOGY LABORATORY
Call Details Advanced Grant (AdG), LS3, ERC-2011-ADG_20110310
Summary Neural circuits, composed of interconnected neurons, represent the basic unit of the nervous system. One way to understand the highly complex arrangement of cross-talking, serial and parallel circuits is to resolve its developmental and evolutionary emergence. The rationale of the research proposal presented here is to elucidate the complex circuitry of the vertebrate and insect forebrain by comparison to the much simpler and evolutionary ancient “connectome” of the marine annelid Platynereis dumerilii. We will build a unique resource, the Platynereis Neuron Type Atlas, combining, for the first time, neuronal morphologies, axonal projections, cellular expression profiling and developmental lineage for an entire bilaterian brain. We will focus on five days old larvae when most adult neuron types are already present in small number and large part of the axonal scaffold in place.
Building on the Neuron Type Atlas, the second part of the proposal envisages the functional dissection of the Platynereis chemosensory-motor forebrain circuits. A newly developed microfluidics behavioural assay system, together with a cell-based GPCR screening will identify partaking neurons. Zinc finger nuclease-mediated knockout of circuit-specific transcription factors as identified from the Atlas will reveal circuit-specific gene regulatory networks, downstream effector genes and functional characteristics. Laser ablation of GFP-labeled single neurons and axonal connections will yield further insight into the function of circuit components and subcircuits. Given the ancient nature of the Platynereis brain, this research is expected to reveal a simple, developmental and evolutionary “blueprint” for the olfactory circuits in mice and flies and to shed new light on the evolution of information processing in glomeruli and higher-level integration in sensory-associative brain centres.
Summary
Neural circuits, composed of interconnected neurons, represent the basic unit of the nervous system. One way to understand the highly complex arrangement of cross-talking, serial and parallel circuits is to resolve its developmental and evolutionary emergence. The rationale of the research proposal presented here is to elucidate the complex circuitry of the vertebrate and insect forebrain by comparison to the much simpler and evolutionary ancient “connectome” of the marine annelid Platynereis dumerilii. We will build a unique resource, the Platynereis Neuron Type Atlas, combining, for the first time, neuronal morphologies, axonal projections, cellular expression profiling and developmental lineage for an entire bilaterian brain. We will focus on five days old larvae when most adult neuron types are already present in small number and large part of the axonal scaffold in place.
Building on the Neuron Type Atlas, the second part of the proposal envisages the functional dissection of the Platynereis chemosensory-motor forebrain circuits. A newly developed microfluidics behavioural assay system, together with a cell-based GPCR screening will identify partaking neurons. Zinc finger nuclease-mediated knockout of circuit-specific transcription factors as identified from the Atlas will reveal circuit-specific gene regulatory networks, downstream effector genes and functional characteristics. Laser ablation of GFP-labeled single neurons and axonal connections will yield further insight into the function of circuit components and subcircuits. Given the ancient nature of the Platynereis brain, this research is expected to reveal a simple, developmental and evolutionary “blueprint” for the olfactory circuits in mice and flies and to shed new light on the evolution of information processing in glomeruli and higher-level integration in sensory-associative brain centres.
Max ERC Funding
2 489 048 €
Duration
Start date: 2012-03-01, End date: 2017-02-28
Project acronym C18Signaling
Project Regulation of Cellular Growth and Metabolism by C18:0
Researcher (PI) Aurelio TELEMAN
Host Institution (HI) DEUTSCHES KREBSFORSCHUNGSZENTRUM HEIDELBERG
Call Details Consolidator Grant (CoG), LS3, ERC-2016-COG
Summary My lab studies how cells regulate their growth and metabolism during normal development and in disease. Recent work in my lab, published last year in Nature, identified the metabolite stearic acid (C18:0) as a novel regulator of mitochondrial function. We showed that dietary C18:0 acts via a novel signaling route whereby it covalently modifies the cell-surface Transferrin Receptor (TfR1) to regulate mitochondrial morphology. We found that modification of TfR1 by C18:0 ('stearoylation') is analogous to protein palmitoylation by C16:0 - it is a covalent thio-ester link and requires a transferase enzyme. This work made two conceptual contributions. 1) It uncovered a novel signaling route regulating mitochondrial function. 2) Relevant to this grant application, we found by mass spectrometry multiple other proteins that are stearoylated in mammalian cells. This thereby opens a new avenue of research, suggesting that C18:0 signals via several target proteins to regulate cellular growth and metabolism. I propose here to study this C18:0 signaling.
To study C18:0 signaling we will exploit tools recently developed in my lab to 1) identify as complete a set as possible of proteins that are stearoylated in human and Drosophila cells, thereby characterizing the cellular 'stearylome', 2) study how stearoylation affects the molecular function of these target proteins, and thereby cellular growth and metabolism, and 3) study how stearoylation is added, and possibly removed, from target proteins.
This work will change the way we view C18:0 from simply being a metabolite to being an important dietary signaling molecule that links nutritional uptake to cellular physiology. Via unknown mechanisms, dietary C18:0 is clinically known to have special properties for cardiovascular risk. Hence this proposal, discovering how C18:0 signals to regulate cells, will have implications for both normal development and for disease.
Summary
My lab studies how cells regulate their growth and metabolism during normal development and in disease. Recent work in my lab, published last year in Nature, identified the metabolite stearic acid (C18:0) as a novel regulator of mitochondrial function. We showed that dietary C18:0 acts via a novel signaling route whereby it covalently modifies the cell-surface Transferrin Receptor (TfR1) to regulate mitochondrial morphology. We found that modification of TfR1 by C18:0 ('stearoylation') is analogous to protein palmitoylation by C16:0 - it is a covalent thio-ester link and requires a transferase enzyme. This work made two conceptual contributions. 1) It uncovered a novel signaling route regulating mitochondrial function. 2) Relevant to this grant application, we found by mass spectrometry multiple other proteins that are stearoylated in mammalian cells. This thereby opens a new avenue of research, suggesting that C18:0 signals via several target proteins to regulate cellular growth and metabolism. I propose here to study this C18:0 signaling.
To study C18:0 signaling we will exploit tools recently developed in my lab to 1) identify as complete a set as possible of proteins that are stearoylated in human and Drosophila cells, thereby characterizing the cellular 'stearylome', 2) study how stearoylation affects the molecular function of these target proteins, and thereby cellular growth and metabolism, and 3) study how stearoylation is added, and possibly removed, from target proteins.
This work will change the way we view C18:0 from simply being a metabolite to being an important dietary signaling molecule that links nutritional uptake to cellular physiology. Via unknown mechanisms, dietary C18:0 is clinically known to have special properties for cardiovascular risk. Hence this proposal, discovering how C18:0 signals to regulate cells, will have implications for both normal development and for disease.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-03-01, End date: 2022-02-28
