Project acronym ACE-OF-SPACE
Project Analysis, control, and engineering of spatiotemporal pattern formation
Researcher (PI) Patrick MueLLER
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Country Germany
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 ADHESWITCHES
Project Adhesion switches in cancer and development: from in vivo to synthetic biology
Researcher (PI) Mari Johanna Ivaska
Host Institution (HI) TURUN YLIOPISTO
Country Finland
Call Details Consolidator Grant (CoG), LS3, ERC-2013-CoG
Summary Integrins are transmembrane cell adhesion receptors controlling cell proliferation and migration. Our objective is to gain fundamentally novel mechanistic insight into the emerging new roles of integrins in cancer and to generate a road map of integrin dependent pathways critical in mammary gland development and integrin signalling thus opening new targets for therapeutic interventions. We will combine an in vivo based translational approach with cell and molecular biological studies aiming to identify entirely novel concepts in integrin function using cutting edge techniques and synthetic-biology tools.
The specific objectives are:
1) Integrin inactivation in branching morphogenesis and cancer invasion. Integrins regulate mammary gland development and cancer invasion but the role of integrin inactivating proteins in these processes is currently completely unknown. We will investigate this using genetically modified mice, ex-vivo organoid models and human tissues with the aim to identify beneficial combinational treatments against cancer invasion.
2) Endosomal adhesomes – cross-talk between integrin activity and integrin “inside-in signaling”. We hypothesize that endocytosed active integrins engage in specialized endosomal signaling that governs cell survival especially in cancer. RNAi cell arrays, super-resolution STED imaging and endosomal proteomics will be used to investigate integrin signaling in endosomes.
3) Spatio-temporal co-ordination of adhesion and endocytosis. Several cytosolic proteins compete for integrin binding to regulate activation, endocytosis and recycling. Photoactivatable protein-traps and predefined matrix micropatterns will be employed to mechanistically dissect the spatio-temporal dynamics and hierarchy of their recruitment.
We will employ innovative and unconventional techniques to address three major unanswered questions in the field and significantly advance our understanding of integrin function in development and cancer.
Summary
Integrins are transmembrane cell adhesion receptors controlling cell proliferation and migration. Our objective is to gain fundamentally novel mechanistic insight into the emerging new roles of integrins in cancer and to generate a road map of integrin dependent pathways critical in mammary gland development and integrin signalling thus opening new targets for therapeutic interventions. We will combine an in vivo based translational approach with cell and molecular biological studies aiming to identify entirely novel concepts in integrin function using cutting edge techniques and synthetic-biology tools.
The specific objectives are:
1) Integrin inactivation in branching morphogenesis and cancer invasion. Integrins regulate mammary gland development and cancer invasion but the role of integrin inactivating proteins in these processes is currently completely unknown. We will investigate this using genetically modified mice, ex-vivo organoid models and human tissues with the aim to identify beneficial combinational treatments against cancer invasion.
2) Endosomal adhesomes – cross-talk between integrin activity and integrin “inside-in signaling”. We hypothesize that endocytosed active integrins engage in specialized endosomal signaling that governs cell survival especially in cancer. RNAi cell arrays, super-resolution STED imaging and endosomal proteomics will be used to investigate integrin signaling in endosomes.
3) Spatio-temporal co-ordination of adhesion and endocytosis. Several cytosolic proteins compete for integrin binding to regulate activation, endocytosis and recycling. Photoactivatable protein-traps and predefined matrix micropatterns will be employed to mechanistically dissect the spatio-temporal dynamics and hierarchy of their recruitment.
We will employ innovative and unconventional techniques to address three major unanswered questions in the field and significantly advance our understanding of integrin function in development and cancer.
Max ERC Funding
1 887 910 €
Duration
Start date: 2014-05-01, End date: 2019-04-30
Project acronym APOSITE
Project Apoptotic foci: composition, structure and dynamics
Researcher (PI) Ana GARCIA SAEZ
Host Institution (HI) UNIVERSITAET ZU KOELN
Country Germany
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 AutoRecon
Project Molecular mechanisms of autophagosome formation during selective autophagy
Researcher (PI) Sascha Martens
Host Institution (HI) UNIVERSITAT WIEN
Country Austria
Call Details Consolidator Grant (CoG), LS3, ERC-2014-CoG
Summary I propose to study how eukaryotic cells generate autophagosomes, organelles bounded by a double membrane. These are formed during autophagy and mediate the degradation of cytoplasmic substances within the lysosomal compartment. Autophagy thereby protects the organism from pathological conditions such as neurodegeneration, cancer and infections. Many core factors required for autophagosome formation have been identified but the order in which they act and their mode of action is still unclear. We will use a combination of biochemical and cell biological approaches to elucidate the choreography and mechanism of these core factors. In particular, we will focus on selective autophagy and determine how the autophagic machinery generates an autophagosome that selectively contains the cargo.
To this end we will focus on the cytoplasm-to-vacuole-targeting pathway in S. cerevisiae that mediates the constitutive delivery of the prApe1 enzyme into the vacuole. We will use cargo mimetics or prApe1 complexes in combination with purified autophagy proteins and vesicles to reconstitute the process and so determine which factors are both necessary and sufficient for autophagosome formation, as well as elucidating their mechanism of action.
In parallel we will study selective autophagosome formation in human cells. This will reveal common principles and special adaptations. In particular, we will use cell lysates from genome-edited cells in combination with purified autophagy proteins to reconstitute selective autophagosome formation around ubiquitin-positive cargo material. The insights and hypotheses obtained from these reconstituted systems will be validated using cell biological approaches.
Taken together, our experiments will allow us to delineate the major steps of autophagosome formation during selective autophagy. Our results will yield detailed insights into how cells form and shape organelles in a de novo manner, which is major question in cell- and developmental biology.
Summary
I propose to study how eukaryotic cells generate autophagosomes, organelles bounded by a double membrane. These are formed during autophagy and mediate the degradation of cytoplasmic substances within the lysosomal compartment. Autophagy thereby protects the organism from pathological conditions such as neurodegeneration, cancer and infections. Many core factors required for autophagosome formation have been identified but the order in which they act and their mode of action is still unclear. We will use a combination of biochemical and cell biological approaches to elucidate the choreography and mechanism of these core factors. In particular, we will focus on selective autophagy and determine how the autophagic machinery generates an autophagosome that selectively contains the cargo.
To this end we will focus on the cytoplasm-to-vacuole-targeting pathway in S. cerevisiae that mediates the constitutive delivery of the prApe1 enzyme into the vacuole. We will use cargo mimetics or prApe1 complexes in combination with purified autophagy proteins and vesicles to reconstitute the process and so determine which factors are both necessary and sufficient for autophagosome formation, as well as elucidating their mechanism of action.
In parallel we will study selective autophagosome formation in human cells. This will reveal common principles and special adaptations. In particular, we will use cell lysates from genome-edited cells in combination with purified autophagy proteins to reconstitute selective autophagosome formation around ubiquitin-positive cargo material. The insights and hypotheses obtained from these reconstituted systems will be validated using cell biological approaches.
Taken together, our experiments will allow us to delineate the major steps of autophagosome formation during selective autophagy. Our results will yield detailed insights into how cells form and shape organelles in a de novo manner, which is major question in cell- and developmental biology.
Max ERC Funding
1 999 640 €
Duration
Start date: 2016-03-01, End date: 2021-02-28
Project acronym BACTIN
Project Shaping the bacterial cell wall: the actin-like cytoskeleton, from single molecules to morphogenesis and antimicrobials
Researcher (PI) Rut CARBALLIDO LOPEZ
Host Institution (HI) INSTITUT NATIONAL DE RECHERCHE POUR L'AGRICULTURE, L'ALIMENTATION ET L'ENVIRONNEMENT
Country France
Call Details Consolidator Grant (CoG), LS3, ERC-2017-COG
Summary One of the ultimate goals in cell biology is to understand how cells determine their shape. In bacteria, the cell wall and the actin-like (MreB) cytoskeleton are major determinants of cell shape. As a hallmark of microbial life, the external cell wall is the most conspicuous macromolecule expanding in concert with cell growth and one of the most prominent targets for antibiotics. Despite decades of study, the mechanism of cell wall morphogenesis remains poorly understood. In rod-shaped bacteria, actin-like MreB proteins assemble into disconnected membrane-associated structures (patches) that move processively around the cell periphery and are thought to control shape by spatiotemporally organizing macromolecular machineries that effect sidewall elongation. However, the ultrastructure of MreB assemblies and the mechanistic details underlying their morphogenetic function remain to be elucidated.
The aim of this project is to combine ground-breaking light microscopy and spectroscopy techniques with cutting-edge genetic, biochemical and systems biology approaches available in the model rod-shaped bacterium Bacillus subtilis to elucidate how MreB and cell wall biosynthetic enzymes collectively act to build a cell. Within this context, new features of MreB assemblies will be determined in vivo and in vitro, and a “toolbox” of approaches to determine the modes of action of antibiotics targeting cell wall processes will be developed. Parameters measured by the different approaches will be used to refine a mathematical model aiming to quantitatively describe the features of bacterial cell wall growth. The long-term goals of BActin are to understand general principles of bacterial cell morphogenesis and to provide mechanistic templates and new reporters for the screening of novel antibiotics.
Summary
One of the ultimate goals in cell biology is to understand how cells determine their shape. In bacteria, the cell wall and the actin-like (MreB) cytoskeleton are major determinants of cell shape. As a hallmark of microbial life, the external cell wall is the most conspicuous macromolecule expanding in concert with cell growth and one of the most prominent targets for antibiotics. Despite decades of study, the mechanism of cell wall morphogenesis remains poorly understood. In rod-shaped bacteria, actin-like MreB proteins assemble into disconnected membrane-associated structures (patches) that move processively around the cell periphery and are thought to control shape by spatiotemporally organizing macromolecular machineries that effect sidewall elongation. However, the ultrastructure of MreB assemblies and the mechanistic details underlying their morphogenetic function remain to be elucidated.
The aim of this project is to combine ground-breaking light microscopy and spectroscopy techniques with cutting-edge genetic, biochemical and systems biology approaches available in the model rod-shaped bacterium Bacillus subtilis to elucidate how MreB and cell wall biosynthetic enzymes collectively act to build a cell. Within this context, new features of MreB assemblies will be determined in vivo and in vitro, and a “toolbox” of approaches to determine the modes of action of antibiotics targeting cell wall processes will be developed. Parameters measured by the different approaches will be used to refine a mathematical model aiming to quantitatively describe the features of bacterial cell wall growth. The long-term goals of BActin are to understand general principles of bacterial cell morphogenesis and to provide mechanistic templates and new reporters for the screening of novel antibiotics.
Max ERC Funding
1 902 195 €
Duration
Start date: 2019-02-01, End date: 2024-01-31
Project acronym bi-BLOCK
Project Building and bypassing plant polyspermy blocks
Researcher (PI) Rita Helene Gross-Hardt
Host Institution (HI) UNIVERSITAET BREMEN
Country Germany
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: 2021-09-30
Project acronym BinD
Project Mitotic Bookmarking, Stem Cells and early Development
Researcher (PI) Pablo Navarro Gil
Host Institution (HI) INSTITUT PASTEUR
Country France
Call Details Consolidator Grant (CoG), LS3, ERC-2017-COG
Summary The goal of this proposal is to deliver a new theoretical framework to understand how transcription factors (TFs) sustain cell identity during developmental processes. Recognised as key drivers of cell fate acquisition, TFs are currently not considered to directly contribute to the mitotic inheritance of chromatin states. Instead, these are passively propagated through cell division by a variety of epigenetic marks. Recent discoveries, including by our lab, challenge this view: developmental TFs may impact the propagation of regulatory information from mother to daughter cells through a process known as mitotic bookmarking. This hypothesis, largely overlooked by mainstream epigenetic research during the last two decades, will be investigated in embryo-derived stem cells and during early mouse development. Indeed, these immature cell identities are largely independent from canonical epigenetic repression; hence, current models cannot account for their properties. We will comprehensively identify mitotic bookmarking factors in stem cells and early embryos, establish their function in stem cell self-renewal, cell fate acquisition and dissect how they contribute to chromatin regulation in mitosis. This will allow us to study the relationships between bookmarking factors and other mechanisms of epigenetic inheritance. To achieve this, unique techniques to modulate protein activity and histone modifications specifically in mitotic cells will be established. Thus, a mechanistic understanding of how mitosis influences gene regulation and of how mitotic bookmarking contributes to the propagation of immature cell identities will be delivered. Based on robust preliminary data, we anticipate the discovery of new functions for TFs in several genetic and epigenetic processes. This knowledge should have a wide impact on chromatin biology and cell fate studies as well as in other fields studying processes dominated by TFs and cell proliferation.
Summary
The goal of this proposal is to deliver a new theoretical framework to understand how transcription factors (TFs) sustain cell identity during developmental processes. Recognised as key drivers of cell fate acquisition, TFs are currently not considered to directly contribute to the mitotic inheritance of chromatin states. Instead, these are passively propagated through cell division by a variety of epigenetic marks. Recent discoveries, including by our lab, challenge this view: developmental TFs may impact the propagation of regulatory information from mother to daughter cells through a process known as mitotic bookmarking. This hypothesis, largely overlooked by mainstream epigenetic research during the last two decades, will be investigated in embryo-derived stem cells and during early mouse development. Indeed, these immature cell identities are largely independent from canonical epigenetic repression; hence, current models cannot account for their properties. We will comprehensively identify mitotic bookmarking factors in stem cells and early embryos, establish their function in stem cell self-renewal, cell fate acquisition and dissect how they contribute to chromatin regulation in mitosis. This will allow us to study the relationships between bookmarking factors and other mechanisms of epigenetic inheritance. To achieve this, unique techniques to modulate protein activity and histone modifications specifically in mitotic cells will be established. Thus, a mechanistic understanding of how mitosis influences gene regulation and of how mitotic bookmarking contributes to the propagation of immature cell identities will be delivered. Based on robust preliminary data, we anticipate the discovery of new functions for TFs in several genetic and epigenetic processes. This knowledge should have a wide impact on chromatin biology and cell fate studies as well as in other fields studying processes dominated by TFs and cell proliferation.
Max ERC Funding
1 900 844 €
Duration
Start date: 2018-09-01, End date: 2023-08-31
Project acronym BRIDGING
Project The function of membrane tethering in plant intercellular communication
Researcher (PI) Emmanuelle Maria Francoise Bayer
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Consolidator Grant (CoG), LS3, ERC-2017-COG
Summary Intercellular communication is critical for multicellularity. It coordinates the activities within individual cells to support the function of an organism as a whole. Plants have developed remarkable cellular machines -the Plasmodesmata (PD) pores- which interconnect every single cell within the plant body, establishing direct membrane and cytoplasmic continuity, a situation unique to plants. PD are indispensable for plant life. They control the flux of molecules between cells and are decisive for development, environmental adaptation and defence signalling. However, how PD integrate signalling to coordinate responses at a multicellular level remains unclear.
A striking feature of PD organisation, setting them apart from animal cell junctions, is a strand of endoplasmic reticulum (ER) running through the pore, tethered extremely tight (~10nm) to the plasma membrane (PM) by unidentified “spokes”. To date, the function of ER-PM contacts at PD remains a complete enigma. We don’t know how and why the two organelles come together at PD cellular junctions.
I recently proposed that ER-PM tethering is in fact central to PD function. In this project I will investigate the question of how integrated cellular responses benefit from organelle cross-talk at PD. The project integrates proteomic/bioinformatic approaches, biophysical/modelling methods and ultra-high resolution 3D imaging into molecular cell biology of plant cell-to-cell communication and will, for the first time, directly address the mechanism and function of ER-PM contacts at PD. We will pursue three complementary objectives to attain our goal: 1) Identify the mechanisms of PD membrane-tethering at the molecular level 2) Elucidate the dynamics and 3D architecture of ER-PM contact sites at PD 3) Uncover the function of ER-PM apposition for plant intercellular communication. Overall, the project will pioneer a radically new perspective on PD-mediated cell-to-cell communication, a fundamental aspect of plant biology
Summary
Intercellular communication is critical for multicellularity. It coordinates the activities within individual cells to support the function of an organism as a whole. Plants have developed remarkable cellular machines -the Plasmodesmata (PD) pores- which interconnect every single cell within the plant body, establishing direct membrane and cytoplasmic continuity, a situation unique to plants. PD are indispensable for plant life. They control the flux of molecules between cells and are decisive for development, environmental adaptation and defence signalling. However, how PD integrate signalling to coordinate responses at a multicellular level remains unclear.
A striking feature of PD organisation, setting them apart from animal cell junctions, is a strand of endoplasmic reticulum (ER) running through the pore, tethered extremely tight (~10nm) to the plasma membrane (PM) by unidentified “spokes”. To date, the function of ER-PM contacts at PD remains a complete enigma. We don’t know how and why the two organelles come together at PD cellular junctions.
I recently proposed that ER-PM tethering is in fact central to PD function. In this project I will investigate the question of how integrated cellular responses benefit from organelle cross-talk at PD. The project integrates proteomic/bioinformatic approaches, biophysical/modelling methods and ultra-high resolution 3D imaging into molecular cell biology of plant cell-to-cell communication and will, for the first time, directly address the mechanism and function of ER-PM contacts at PD. We will pursue three complementary objectives to attain our goal: 1) Identify the mechanisms of PD membrane-tethering at the molecular level 2) Elucidate the dynamics and 3D architecture of ER-PM contact sites at PD 3) Uncover the function of ER-PM apposition for plant intercellular communication. Overall, the project will pioneer a radically new perspective on PD-mediated cell-to-cell communication, a fundamental aspect of plant biology
Max ERC Funding
1 999 840 €
Duration
Start date: 2018-06-01, End date: 2023-05-31
Project acronym C18Signaling
Project Regulation of Cellular Growth and Metabolism by C18:0
Researcher (PI) Aurelio TELEMAN
Host Institution (HI) DEUTSCHES KREBSFORSCHUNGSZENTRUM HEIDELBERG
Country Germany
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
Project acronym CELLFITNESS
Project Active Mechanisms of Cell Selection: From Cell Competition to Cell Fitness
Researcher (PI) Eduardo Moreno Lampaya
Host Institution (HI) FUNDACAO D. ANNA SOMMER CHAMPALIMAUD E DR. CARLOS MONTEZ CHAMPALIMAUD
Country Portugal
Call Details Consolidator Grant (CoG), LS3, ERC-2013-CoG
Summary The molecular mechanisms that mediate cell competition, cell fitness and cell selection is gaining interest. With innovative approaches, molecules and ground-breaking hypothesis, this field of research can help understand several biological processes such as development, cancer and tissue degeneration. The project has 3 clear and ambitious objectives: 1. We propose to identify all the key genes mediating cell competition and their molecular mechanisms. In order to reach this objective we will use data from two whole genome screens in Drosophila where we have identified 7 key genes. By the end of this CoG grant, we should have no big gaps in our knowledge of how slow dividing cells are recognised and eliminated in Drosophila. 2. In addition, we will explore how general the cell competition pathways are and how they can impact biomedical research, with a focus in cancer and tissue degeneration. The interest in cancer is based on experiments in Drosophila and mice where we and others have found that an active process of cell selection determines tumour growth. Preliminary results suggest that the pathways identified do not only play important roles in the elimination of slow dividing cells, but also during cancer initiation and progression. 3. We will further explore the role of cell competition in neuronal selection, specially during neurodegeneration, development of the retina and adult brain regeneration in Drosophila. This proposal is of an interdisciplinary nature because it takes a basic cellular mechanism (the genetic pathways that select cells within tissues) and crosses boundaries between different fields of research: development, cancer, regeneration and tissue degeneration. In this ERC CoG proposal, we are committed to continue our efforts from basic science to biomedical approaches. The phenomena of cell competition and its participating genes have the potential to discover novel biomarkers and therapeutic strategies against cancer and tissue degeneration.
Summary
The molecular mechanisms that mediate cell competition, cell fitness and cell selection is gaining interest. With innovative approaches, molecules and ground-breaking hypothesis, this field of research can help understand several biological processes such as development, cancer and tissue degeneration. The project has 3 clear and ambitious objectives: 1. We propose to identify all the key genes mediating cell competition and their molecular mechanisms. In order to reach this objective we will use data from two whole genome screens in Drosophila where we have identified 7 key genes. By the end of this CoG grant, we should have no big gaps in our knowledge of how slow dividing cells are recognised and eliminated in Drosophila. 2. In addition, we will explore how general the cell competition pathways are and how they can impact biomedical research, with a focus in cancer and tissue degeneration. The interest in cancer is based on experiments in Drosophila and mice where we and others have found that an active process of cell selection determines tumour growth. Preliminary results suggest that the pathways identified do not only play important roles in the elimination of slow dividing cells, but also during cancer initiation and progression. 3. We will further explore the role of cell competition in neuronal selection, specially during neurodegeneration, development of the retina and adult brain regeneration in Drosophila. This proposal is of an interdisciplinary nature because it takes a basic cellular mechanism (the genetic pathways that select cells within tissues) and crosses boundaries between different fields of research: development, cancer, regeneration and tissue degeneration. In this ERC CoG proposal, we are committed to continue our efforts from basic science to biomedical approaches. The phenomena of cell competition and its participating genes have the potential to discover novel biomarkers and therapeutic strategies against cancer and tissue degeneration.
Max ERC Funding
1 968 062 €
Duration
Start date: 2014-06-01, End date: 2019-05-31
