Project acronym CENDUP
Project Decoding the mechanisms of centrosome duplication
Researcher (PI) Pierre Gönczy
Host Institution (HI) ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Centrosome duplication entails the formation of a single procentriole next to each centriole once per cell cycle. The mechanisms governing procentriole formation are poorly understood and constitute a fundamental open question in cell biology. We will launch an innovative multidisciplinary research program to gain significant insight into these mechanisms using C. elegans and human cells. This research program is also expected to have a significant impact by contributing important novel assays to the field. Six specific aims will be pursued: 1) SAS-6 as a ZYG-1 substrate: mechanisms of procentriole formation in C. elegans. We will test in vivo the consequence of SAS-6 phosphorylation by ZYG-1. 2) Biochemical and structural analysis of SAS-6-containing macromolecular complexes (SAMACs). We will isolate and characterize SAMACs from C. elegans embryos and human cells, and analyze their structure using single-particle electron microscopy. 3) Novel cell-free assay for procentriole formation in human cells. We will develop such an assay and use it to test whether SAMACs can direct procentriole formation and whether candidate proteins are needed at centrioles or in the cytoplasm. 4) Mapping interactions between centriolar proteins in live human cells. We will use chemical methods developed by our collaborators to probe interactions between HsSAS-6 and centriolar proteins in a time- and space-resolved manner. 5) Functional genomic and chemical genetic screens in human cells. We will conduct high-throughput fluorescence-based screens in human cells to identify novel genes required for procentriole formation and small molecule inhibitors of this process. 6) Mechanisms underlying differential centriolar maintenance in the germline. In C. elegans, we will characterize how the sas-1 locus is required for centriole maintenance during spermatogenesis, as well as analyze centriole elimination during oogenesis and identify components needed for this process
Summary
Centrosome duplication entails the formation of a single procentriole next to each centriole once per cell cycle. The mechanisms governing procentriole formation are poorly understood and constitute a fundamental open question in cell biology. We will launch an innovative multidisciplinary research program to gain significant insight into these mechanisms using C. elegans and human cells. This research program is also expected to have a significant impact by contributing important novel assays to the field. Six specific aims will be pursued: 1) SAS-6 as a ZYG-1 substrate: mechanisms of procentriole formation in C. elegans. We will test in vivo the consequence of SAS-6 phosphorylation by ZYG-1. 2) Biochemical and structural analysis of SAS-6-containing macromolecular complexes (SAMACs). We will isolate and characterize SAMACs from C. elegans embryos and human cells, and analyze their structure using single-particle electron microscopy. 3) Novel cell-free assay for procentriole formation in human cells. We will develop such an assay and use it to test whether SAMACs can direct procentriole formation and whether candidate proteins are needed at centrioles or in the cytoplasm. 4) Mapping interactions between centriolar proteins in live human cells. We will use chemical methods developed by our collaborators to probe interactions between HsSAS-6 and centriolar proteins in a time- and space-resolved manner. 5) Functional genomic and chemical genetic screens in human cells. We will conduct high-throughput fluorescence-based screens in human cells to identify novel genes required for procentriole formation and small molecule inhibitors of this process. 6) Mechanisms underlying differential centriolar maintenance in the germline. In C. elegans, we will characterize how the sas-1 locus is required for centriole maintenance during spermatogenesis, as well as analyze centriole elimination during oogenesis and identify components needed for this process
Max ERC Funding
2 004 155 €
Duration
Start date: 2009-04-01, End date: 2014-03-31
Project acronym DROSOPHILASIGNALING
Project Signaling Pathways Controlling Patterning, Growth and Final Size of Drosophila Limbs
Researcher (PI) Konrad Basler
Host Institution (HI) UNIVERSITAT ZURICH
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Developmental biology seeks not only to learn more about the fundamental processes of growth and pattern per se, but to understand how they synergize to enable the morphogenesis of multicellular organisms. Our goal is to perform real-time analyses of these developmental processes in an intact developing organ. By applying a vital imaging approach, we can circumvent the normal limitations of inferring cellular dynamics from static images or molecular data, and obtain the real dynamic view of growth and patterning. The wing imaginal disc of Drosophila, which starts out as a simple epithelial structure and gives rise to a precisely structured adult limb, will serve as an ideal model system. This system has the combined advantages of relative simplicity and genetic tractability. We will create several innovations that expand the current toolkit and thus facilitate the detailed dissection of growth and patterning. A key early step will be to develop novel reporters to dynamically and faithfully monitor signaling cascades involved in growth and patterning, such as the Dpp and Hippo pathways. We will also implement quantification techniques that are currently being set up in collaboration with an experimental physicist, to deduce, and alter, the mechanical forces that develop in the cells of a growing tissue. The large amount of quantitative data that will be generated allow us derive computational models of the individual pathways and their interaction. The focus of the study will be to answer the following questions: 1) Is the Hippo pathway regulated spatially and temporally, and by what signaling pathways? 2) Do mechanical forces play a pivotal controlling role in organ morphogenesis? 3) What are the global effects on growth, when pathways controlling patterning, cell competition or compensatory proliferation are perturbed? The proposed project will bring the approaches taken to define the mechanisms underlying and controlling growth and patterning to the next level.
Summary
Developmental biology seeks not only to learn more about the fundamental processes of growth and pattern per se, but to understand how they synergize to enable the morphogenesis of multicellular organisms. Our goal is to perform real-time analyses of these developmental processes in an intact developing organ. By applying a vital imaging approach, we can circumvent the normal limitations of inferring cellular dynamics from static images or molecular data, and obtain the real dynamic view of growth and patterning. The wing imaginal disc of Drosophila, which starts out as a simple epithelial structure and gives rise to a precisely structured adult limb, will serve as an ideal model system. This system has the combined advantages of relative simplicity and genetic tractability. We will create several innovations that expand the current toolkit and thus facilitate the detailed dissection of growth and patterning. A key early step will be to develop novel reporters to dynamically and faithfully monitor signaling cascades involved in growth and patterning, such as the Dpp and Hippo pathways. We will also implement quantification techniques that are currently being set up in collaboration with an experimental physicist, to deduce, and alter, the mechanical forces that develop in the cells of a growing tissue. The large amount of quantitative data that will be generated allow us derive computational models of the individual pathways and their interaction. The focus of the study will be to answer the following questions: 1) Is the Hippo pathway regulated spatially and temporally, and by what signaling pathways? 2) Do mechanical forces play a pivotal controlling role in organ morphogenesis? 3) What are the global effects on growth, when pathways controlling patterning, cell competition or compensatory proliferation are perturbed? The proposed project will bring the approaches taken to define the mechanisms underlying and controlling growth and patterning to the next level.
Max ERC Funding
2 310 000 €
Duration
Start date: 2009-02-01, End date: 2014-01-31
Project acronym EDIP
Project Evolution of Development In Plants
Researcher (PI) Jane Alison Langdale
Host Institution (HI) THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Different morphologies evolve in different organisms in response to changing environments. As land plants evolved, developmental mechanisms were either generated de novo, or were recruited from existing toolkits and adapted to facilitate changes in form. Some of these changes occurred once, others on multiple occasions, and others were gained and then subsequently lost in a subset of lineages. Why have certain forms survived and others not? Why does a fern look different from a flowering plant, and why should developmental biologists care? By determining how many different ways there are to generate a particular morphology, we gain an understanding of whether a particular transition is constrained. This basic information allows an assessment of the extent to which genetic variation can modify developmental mechanisms and an indication of the degree of developmental plasticity that is possible and/or tolerated both within and between species. This proposal aims to characterize the developmental mechanisms that underpin the diverse shoot forms seen in extant plant species. The main goal is to compare developmental mechanisms that operate in vegetative shoots of bryophytes, lycophytes, ferns and angiosperms, with a view to understanding the constraints that limit morphological variation. Specifically, we will investigate the developmental basis of three major innovations that altered the morphology of vegetative shoots during land plant evolution: 1) formation of a multi-cellular embryo; 2) organization of apical growth centres and 3) patterning of leaves in distinct spatial arrangements along the shoot. To facilitate progress we also aim to develop transgenic methods, create mutant populations and generate digital transcriptomes for model species at key phylogenetic nodes. The proposed work will generate scenarios to explain how land plant form evolved and perhaps more importantly, how it could change in the future.
Summary
Different morphologies evolve in different organisms in response to changing environments. As land plants evolved, developmental mechanisms were either generated de novo, or were recruited from existing toolkits and adapted to facilitate changes in form. Some of these changes occurred once, others on multiple occasions, and others were gained and then subsequently lost in a subset of lineages. Why have certain forms survived and others not? Why does a fern look different from a flowering plant, and why should developmental biologists care? By determining how many different ways there are to generate a particular morphology, we gain an understanding of whether a particular transition is constrained. This basic information allows an assessment of the extent to which genetic variation can modify developmental mechanisms and an indication of the degree of developmental plasticity that is possible and/or tolerated both within and between species. This proposal aims to characterize the developmental mechanisms that underpin the diverse shoot forms seen in extant plant species. The main goal is to compare developmental mechanisms that operate in vegetative shoots of bryophytes, lycophytes, ferns and angiosperms, with a view to understanding the constraints that limit morphological variation. Specifically, we will investigate the developmental basis of three major innovations that altered the morphology of vegetative shoots during land plant evolution: 1) formation of a multi-cellular embryo; 2) organization of apical growth centres and 3) patterning of leaves in distinct spatial arrangements along the shoot. To facilitate progress we also aim to develop transgenic methods, create mutant populations and generate digital transcriptomes for model species at key phylogenetic nodes. The proposed work will generate scenarios to explain how land plant form evolved and perhaps more importantly, how it could change in the future.
Max ERC Funding
2 230 732 €
Duration
Start date: 2009-07-01, End date: 2015-06-30
Project acronym MAMMASTEM
Project Molecular mechanisms of the regulation of mammary stem cell homeostasis and their subversion in cancer
Researcher (PI) Pier Paolo Di Fiore
Host Institution (HI) IFOM FONDAZIONE ISTITUTO FIRC DI ONCOLOGIA MOLECOLARE
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Stem cells (SCs) are thought to be integral to the development and progression of cancer, and their eradication may be essential for the cure of cancer. Yet, direct proof is lacking due to our poor understanding of the molecular differences between normal and cancer SCs. We will investigate normal and cancer mammary stem cells (MSCs) by focusing on the role of the cell fate determinant Numb in two signaling axes: Numb:Notch and Numb:p53. Numb is a tumor suppressor in human breast cancer. Its expression is lost, through increased degradation, in ~50% of breast cancers. These Numbneg cancers display overall poorer prognosis. Mechanistically, loss of Numb causes increased Notch signaling and decreased p53 signaling. Thus, Numb controls both an oncogenic pathway (the Numb:Notch axis) and a tumor suppressor one (the Numb:p53 axis). We showed that Numb is asymmetrically partitioned at the first division of normal MSCs and hypothesize that loss of Numb affects the kinetics of division and MSC fate. Our specific aims are to: 1. Define the role of the Numb:Notch and Numb:p53 axes in normal and cancer MSCs. We will exploit our capacity to propagate and isolate MSCs to near-purity, for biological, biochemical and omics approaches. In this task, we will integrate knowledge derived from the analysis of real human cancers and of genetically-defined mouse models. 2. Define the broader biological context of Numb impact in stem cell biology, by analyzing the role of endocytosis in MSC fate determination. This is justified by the fact that Numb is an endocytic protein and that data in Drosophila indicate a complex role of endocytosis in cell fate specification. 3. Identify the E3 ligase responsible for Numb degradation in Numbneg breast tumors, in order to obtain druggable targets to restore Numb levels in these tumors. If successful, our work will elucidate major mechanisms of normal and cancer stem cell regulation, and provide tools for SC-specific therapeutic intervention.
Summary
Stem cells (SCs) are thought to be integral to the development and progression of cancer, and their eradication may be essential for the cure of cancer. Yet, direct proof is lacking due to our poor understanding of the molecular differences between normal and cancer SCs. We will investigate normal and cancer mammary stem cells (MSCs) by focusing on the role of the cell fate determinant Numb in two signaling axes: Numb:Notch and Numb:p53. Numb is a tumor suppressor in human breast cancer. Its expression is lost, through increased degradation, in ~50% of breast cancers. These Numbneg cancers display overall poorer prognosis. Mechanistically, loss of Numb causes increased Notch signaling and decreased p53 signaling. Thus, Numb controls both an oncogenic pathway (the Numb:Notch axis) and a tumor suppressor one (the Numb:p53 axis). We showed that Numb is asymmetrically partitioned at the first division of normal MSCs and hypothesize that loss of Numb affects the kinetics of division and MSC fate. Our specific aims are to: 1. Define the role of the Numb:Notch and Numb:p53 axes in normal and cancer MSCs. We will exploit our capacity to propagate and isolate MSCs to near-purity, for biological, biochemical and omics approaches. In this task, we will integrate knowledge derived from the analysis of real human cancers and of genetically-defined mouse models. 2. Define the broader biological context of Numb impact in stem cell biology, by analyzing the role of endocytosis in MSC fate determination. This is justified by the fact that Numb is an endocytic protein and that data in Drosophila indicate a complex role of endocytosis in cell fate specification. 3. Identify the E3 ligase responsible for Numb degradation in Numbneg breast tumors, in order to obtain druggable targets to restore Numb levels in these tumors. If successful, our work will elucidate major mechanisms of normal and cancer stem cell regulation, and provide tools for SC-specific therapeutic intervention.
Max ERC Funding
2 274 862 €
Duration
Start date: 2009-03-01, End date: 2014-02-28
Project acronym MITOSCAFFOLD
Project Mitochondrial membrane organization by protein scaffolds and lipid dynamics
Researcher (PI) Thomas Rudolf Langer
Host Institution (HI) UNIVERSITAET ZU KOELN
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Biological membranes are complex structures built up of a multiplicity of membrane lipids and proteins controlling essential cellular processes. This is exemplified by mitochondria, dynamic double-membrane bound organelles, with essential roles in diverse metabolic and cellular signalling pathways. The mitochondrial inner membrane is considered to be the protein richest cellular membrane, whose functional impairment is associated with aging, myopathies and diverse neurological disorders in human. Recent evidence from our group revealed essential roles of large, ring-like prohibitin complexes in the inner membrane for embryonic development in mice, cell proliferation, resistance against apoptosis, and the maintenance of mitochondrial cristae. Prohibitins comprise a conserved and ubiquitously expressed protein family and are suggested to serve as protein scaffolds in the inner membrane. Defining the network of genetic interactions in yeast, we could establish that prohibitin function depends on the supply of the non-bilayer phospholipids cardiolipin and phosphatidyl ethanolamine and on intramitochondrial lipid trafficking. These findings indicate that mitochondrial function and ultrastructure requires a defined spatial organization of the inner membrane, which is maintained by a defined lipid composition and prohibitins serving as protein scaffolds. Here, we propose a comprehensive analysis of the function of prohibitins and of novel components involved in mitochondrial lipid trafficking and phospholipid biosynthetic pathways. These studies will include genetic as well as biochemical and proteomic approaches and employ both yeast and murine models to integrate the molecular understanding of functionally conserved processes into the physiological context. As components of this system have been linked to cardiomyopathies and diverse neurological disorders, our studies are likely to provide new insight into pathomechanisms of human disease.
Summary
Biological membranes are complex structures built up of a multiplicity of membrane lipids and proteins controlling essential cellular processes. This is exemplified by mitochondria, dynamic double-membrane bound organelles, with essential roles in diverse metabolic and cellular signalling pathways. The mitochondrial inner membrane is considered to be the protein richest cellular membrane, whose functional impairment is associated with aging, myopathies and diverse neurological disorders in human. Recent evidence from our group revealed essential roles of large, ring-like prohibitin complexes in the inner membrane for embryonic development in mice, cell proliferation, resistance against apoptosis, and the maintenance of mitochondrial cristae. Prohibitins comprise a conserved and ubiquitously expressed protein family and are suggested to serve as protein scaffolds in the inner membrane. Defining the network of genetic interactions in yeast, we could establish that prohibitin function depends on the supply of the non-bilayer phospholipids cardiolipin and phosphatidyl ethanolamine and on intramitochondrial lipid trafficking. These findings indicate that mitochondrial function and ultrastructure requires a defined spatial organization of the inner membrane, which is maintained by a defined lipid composition and prohibitins serving as protein scaffolds. Here, we propose a comprehensive analysis of the function of prohibitins and of novel components involved in mitochondrial lipid trafficking and phospholipid biosynthetic pathways. These studies will include genetic as well as biochemical and proteomic approaches and employ both yeast and murine models to integrate the molecular understanding of functionally conserved processes into the physiological context. As components of this system have been linked to cardiomyopathies and diverse neurological disorders, our studies are likely to provide new insight into pathomechanisms of human disease.
Max ERC Funding
1 878 000 €
Duration
Start date: 2009-04-01, End date: 2014-12-31
Project acronym ORGANELL
Project Organelle homeostasis: How are membrane fission and fusion machineries coordinated to regulate size and copy number of a lysosomal compartment?
Researcher (PI) Andreas Mayer
Host Institution (HI) UNIVERSITE DE LAUSANNE
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Yeast vacuoles (lysosomes) will serve as an excellent model system: Vacuoles change copy number and size in the cell cycle and upon shifts of media; due to their large diameter (up to 5 µm) these changes can be assayed by fluorescence microscopy and are amenable to genetic screening. Moreover, an in vitro system for vacuole fusion exists and we recently succeeded in reconstituting also cell-free vacuole fission with purified organelles. We will first build an experimental toolkit for vacuole fission to characterize this reaction in detail. Several approaches will be combined: (1) Identification of fission proteins by mutant screening, as well as by candidate approaches, and their localization relative to the fission site; (2) further developing a system reconstituting in vitro fission and efficient methods to quantitate it. (3) creating organelle chips to synchronously study fission on multiple single vacuoles immobilized in a defined orientation. (4) time-resolved confocal microscopy of fission proteins in vivo and in vitro; (5) biochemical characterization of fission protein associations and their changes during fission. These approaches will identify the vacuolar fission apparatus and help to elucidate its functioning. In a second step we will explore how the fission apparatus physically and functionally interacts with the already well-defined vacuolar membrane fusion machinery. We will characterize the impact of cell cycle regulators and signaling pathways on these interactions. These studies will be pioneering in that they will lead us to a comprehensive description of an organelle fission process and of how membrane fission and fusion components are coordinated to control size and copy number of an organelle.
Summary
Yeast vacuoles (lysosomes) will serve as an excellent model system: Vacuoles change copy number and size in the cell cycle and upon shifts of media; due to their large diameter (up to 5 µm) these changes can be assayed by fluorescence microscopy and are amenable to genetic screening. Moreover, an in vitro system for vacuole fusion exists and we recently succeeded in reconstituting also cell-free vacuole fission with purified organelles. We will first build an experimental toolkit for vacuole fission to characterize this reaction in detail. Several approaches will be combined: (1) Identification of fission proteins by mutant screening, as well as by candidate approaches, and their localization relative to the fission site; (2) further developing a system reconstituting in vitro fission and efficient methods to quantitate it. (3) creating organelle chips to synchronously study fission on multiple single vacuoles immobilized in a defined orientation. (4) time-resolved confocal microscopy of fission proteins in vivo and in vitro; (5) biochemical characterization of fission protein associations and their changes during fission. These approaches will identify the vacuolar fission apparatus and help to elucidate its functioning. In a second step we will explore how the fission apparatus physically and functionally interacts with the already well-defined vacuolar membrane fusion machinery. We will characterize the impact of cell cycle regulators and signaling pathways on these interactions. These studies will be pioneering in that they will lead us to a comprehensive description of an organelle fission process and of how membrane fission and fusion components are coordinated to control size and copy number of an organelle.
Max ERC Funding
2 310 000 €
Duration
Start date: 2009-09-01, End date: 2015-08-31
Project acronym PI3K-III COMPLEX
Project The PI3K-III complex: Function in cell regulation and tumour suppression
Researcher (PI) Harald Alfred Stenmark
Host Institution (HI) UNIVERSITETET I OSLO
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Phosphoinositides (PIs), phosphorylated derivatives of phosphatidylinositol (PtdIns), control cellular functions through recruitment of cytosolic proteins to specific membranes. Among the kinases involved in PI generation, the PI3K-III complex, which catalyzes conversion of PtdIns into PtdIns 3-phosphate (PI3P), is of great interest for several reasons. Firstly, it is required for three topologically related membrane involution processes - the biogenesis of multivesicular endosomes, autophagy, and cytokinesis. Secondly, through its catalytic product this protein complex mediates anti-apoptotic and antiproliferative signalling. Thirdly, several subunits of the PI3K-III complex are known tumour suppressors, making the PI3K-III complex a possible target for cancer therapy and diagnostics. This proposal aims to undertake a systematic analysis of the PI3K-III complex and its functions, and the following key questions will be addressed: How is the PI3K-III complex recruited to specific membranes? How does it control membrane involution and signal transduction? By which mechanisms do subunits of this protein complex serve as tumour suppressors? The project will be divided into seven subprojects, which include (1) characterization of the PI3K-III complex, (2) detection of the PI3K-III product PI3P in cells and tissues, (3) the function of the PI3K-III complex in downregulation of growth factor receptors, (4) the function of the PI3K-III complex in autophagy, (5) the function of the PI3K-III complex in cytokinesis, (6) the function of the PI3K-III complex in cell signalling, and (7) dissecting the tumour suppressor activities of the PI3K-III complex. The analyses will range from protein biochemistry to development of novel imaging probes, siRNA screens for novel PI3P effectors, functional characterization of PI3K-III subunits and PI3P effectors in cell culture models, and tumour suppressor analyses in novel Drosophila models.
Summary
Phosphoinositides (PIs), phosphorylated derivatives of phosphatidylinositol (PtdIns), control cellular functions through recruitment of cytosolic proteins to specific membranes. Among the kinases involved in PI generation, the PI3K-III complex, which catalyzes conversion of PtdIns into PtdIns 3-phosphate (PI3P), is of great interest for several reasons. Firstly, it is required for three topologically related membrane involution processes - the biogenesis of multivesicular endosomes, autophagy, and cytokinesis. Secondly, through its catalytic product this protein complex mediates anti-apoptotic and antiproliferative signalling. Thirdly, several subunits of the PI3K-III complex are known tumour suppressors, making the PI3K-III complex a possible target for cancer therapy and diagnostics. This proposal aims to undertake a systematic analysis of the PI3K-III complex and its functions, and the following key questions will be addressed: How is the PI3K-III complex recruited to specific membranes? How does it control membrane involution and signal transduction? By which mechanisms do subunits of this protein complex serve as tumour suppressors? The project will be divided into seven subprojects, which include (1) characterization of the PI3K-III complex, (2) detection of the PI3K-III product PI3P in cells and tissues, (3) the function of the PI3K-III complex in downregulation of growth factor receptors, (4) the function of the PI3K-III complex in autophagy, (5) the function of the PI3K-III complex in cytokinesis, (6) the function of the PI3K-III complex in cell signalling, and (7) dissecting the tumour suppressor activities of the PI3K-III complex. The analyses will range from protein biochemistry to development of novel imaging probes, siRNA screens for novel PI3P effectors, functional characterization of PI3K-III subunits and PI3P effectors in cell culture models, and tumour suppressor analyses in novel Drosophila models.
Max ERC Funding
2 272 000 €
Duration
Start date: 2010-01-01, End date: 2014-12-31
Project acronym SARA
Project """Endosomal trafficking during morphogenetic signaling and asymmetric cell division"""
Researcher (PI) Marcos Antonio Gonzalez Gaitan
Host Institution (HI) UNIVERSITE DE GENEVE
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary We plan to study the mechanism that controls the growth of animal tissues. We will focus on two types of mitotic modes: asymmetric cell divisions and the morphogen-dependent proliferation of developing cells. Our recent work has shown that endosomal trafficking plays key roles during asymmetric division and during the formation of morphogen gradients. We therefore plan to unravel the biochemical and cell biological mechanisms underlying the key role of endosomes during growth control using Drosophila as a model system and validating it in the Zebrafish, where we will also discover the new endosomal properties that emerged in vertebrates. Our project will pursue two aims: 1. to discover the key lipids and proteins involved in the endosome-mediated control of growth; 2. to study at the biophysical level the signaling and membrane trafficking events that, emanating from the endosomes, mediate the control of growth. We have already shown that endosomal trafficking is essential during the formation of morphogen gradients and asymmetric cell division. This proposal ultimately aims at the physical, molecular and cellular mechanisms behind.
Summary
We plan to study the mechanism that controls the growth of animal tissues. We will focus on two types of mitotic modes: asymmetric cell divisions and the morphogen-dependent proliferation of developing cells. Our recent work has shown that endosomal trafficking plays key roles during asymmetric division and during the formation of morphogen gradients. We therefore plan to unravel the biochemical and cell biological mechanisms underlying the key role of endosomes during growth control using Drosophila as a model system and validating it in the Zebrafish, where we will also discover the new endosomal properties that emerged in vertebrates. Our project will pursue two aims: 1. to discover the key lipids and proteins involved in the endosome-mediated control of growth; 2. to study at the biophysical level the signaling and membrane trafficking events that, emanating from the endosomes, mediate the control of growth. We have already shown that endosomal trafficking is essential during the formation of morphogen gradients and asymmetric cell division. This proposal ultimately aims at the physical, molecular and cellular mechanisms behind.
Max ERC Funding
2 287 785 €
Duration
Start date: 2009-05-01, End date: 2014-04-30
Project acronym STEMCELLMARK
Project LGR receptors mark adult stem cells in multiple mammalian tissues
Researcher (PI) Johannes Carolus Clevers
Host Institution (HI) KONINKLIJKE NEDERLANDSE AKADEMIE VAN WETENSCHAPPEN - KNAW
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Self-renewal and repair of tissues in adult mammals is fueled by rare tissue stem cells. Identification and subsequent study of such adult stem cells depends strictly on the availability of molecular markers. To date, a paucity of single definitive markers has complicated the study of the biology of these rare cells. Our interest in the role of the Wnt pathway in intestinal homeostasis and cancer has led us to exhaustively define the Wnt target gene program shared between these two processes. Within this program, the cell surface receptor-encoding Lgr5 represented a candidate stem cell marker for the intestine. The creation of Lgr5-genetic mouse models subsequently allowed us to definitively identify the Lgr5+ cells as the intestinal stem cells. These stem cells divide every day, yet persist throughout life. Using the same mouse models, we have found that Lgr5 marks stem cells in a variety of other tissues. For two family members with similarly restricted expression domains, Lgr4 and -6, comparable genetic tools have been generated. In this proposal, I aim to exploit these unique genetic tools to study primary adult stem cells in health and disease. This should allow us to outline unique and common characteristics of individual stem cell types, and possibly- define the minimum molecular determinants of stemness. Specifically, I aim: 1. To make a complete inventory of adult stem cells expressing Lgr4, Lgr5 and/or Lgr6 using the transgenic mouse models. 2. To FACS-purify stem cells from selected tissues, and detail their molecular and metabolic characteristics. 3. To genetically define the biological role of the Lgr-family receptors in adult stem cells by gene knockout. 4. To translate these findings to the equivalent human tissues using antibody-based histology and FACS technology. 5. To explore the usefulness of the Lgr proteins as markers of cancer stem cells in human solid tumors.
Summary
Self-renewal and repair of tissues in adult mammals is fueled by rare tissue stem cells. Identification and subsequent study of such adult stem cells depends strictly on the availability of molecular markers. To date, a paucity of single definitive markers has complicated the study of the biology of these rare cells. Our interest in the role of the Wnt pathway in intestinal homeostasis and cancer has led us to exhaustively define the Wnt target gene program shared between these two processes. Within this program, the cell surface receptor-encoding Lgr5 represented a candidate stem cell marker for the intestine. The creation of Lgr5-genetic mouse models subsequently allowed us to definitively identify the Lgr5+ cells as the intestinal stem cells. These stem cells divide every day, yet persist throughout life. Using the same mouse models, we have found that Lgr5 marks stem cells in a variety of other tissues. For two family members with similarly restricted expression domains, Lgr4 and -6, comparable genetic tools have been generated. In this proposal, I aim to exploit these unique genetic tools to study primary adult stem cells in health and disease. This should allow us to outline unique and common characteristics of individual stem cell types, and possibly- define the minimum molecular determinants of stemness. Specifically, I aim: 1. To make a complete inventory of adult stem cells expressing Lgr4, Lgr5 and/or Lgr6 using the transgenic mouse models. 2. To FACS-purify stem cells from selected tissues, and detail their molecular and metabolic characteristics. 3. To genetically define the biological role of the Lgr-family receptors in adult stem cells by gene knockout. 4. To translate these findings to the equivalent human tissues using antibody-based histology and FACS technology. 5. To explore the usefulness of the Lgr proteins as markers of cancer stem cells in human solid tumors.
Max ERC Funding
2 106 000 €
Duration
Start date: 2009-03-01, End date: 2014-02-28
Project acronym SYSARC
Project Systems Biology to understand Plant Architecture
Researcher (PI) Ben J.G. Scheres
Host Institution (HI) WAGENINGEN UNIVERSITY
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Extensive feedback between gene expression state and the cellular environment yields tangled hierarchies . This lack of strictly hierarchical control mechanisms poses a challenge to developmental biologists: the outcome of interaction networks with extensive feedbacks is not intuitive and must be analyzed with analytical tools. Here, I propose a combination of experimental and theoretical approaches to study control mechanisms of plant architecture and their emergent properties. The plant hormone auxin appears to be a major player in developmental patterning and architecture. We and others have shown previously that auxin distribution patterns can self-organize and elaborate different architectures by principles of self-organization. We have discovered that the PLETHORA transcription factors, which form instructive gradients during root development, are involved in early embryo and shoot development as well, and that they constitute a principal component of plant development. Excitingly, PLETHORA genes are regulated by auxin accumulation but they feed back on the most important actors that determine auxin distribution, the PIN proteins. The dynamics of this PLETHORA-PIN loop can display emergent properties that may explain the majority of principal patterning events that determine root and shoot specification as well as branching. Here, I propose to investigate this feedback system in detail using (1) molecular genetic approaches, (2) computer modelling and (3) functional genomics approaches. The projected outcomes are a deep understanding of major control mechanisms for tissue pattern and organismal architecture and general insights into genetic information encoding using tangled hierarchies.
Summary
Extensive feedback between gene expression state and the cellular environment yields tangled hierarchies . This lack of strictly hierarchical control mechanisms poses a challenge to developmental biologists: the outcome of interaction networks with extensive feedbacks is not intuitive and must be analyzed with analytical tools. Here, I propose a combination of experimental and theoretical approaches to study control mechanisms of plant architecture and their emergent properties. The plant hormone auxin appears to be a major player in developmental patterning and architecture. We and others have shown previously that auxin distribution patterns can self-organize and elaborate different architectures by principles of self-organization. We have discovered that the PLETHORA transcription factors, which form instructive gradients during root development, are involved in early embryo and shoot development as well, and that they constitute a principal component of plant development. Excitingly, PLETHORA genes are regulated by auxin accumulation but they feed back on the most important actors that determine auxin distribution, the PIN proteins. The dynamics of this PLETHORA-PIN loop can display emergent properties that may explain the majority of principal patterning events that determine root and shoot specification as well as branching. Here, I propose to investigate this feedback system in detail using (1) molecular genetic approaches, (2) computer modelling and (3) functional genomics approaches. The projected outcomes are a deep understanding of major control mechanisms for tissue pattern and organismal architecture and general insights into genetic information encoding using tangled hierarchies.
Max ERC Funding
2 240 000 €
Duration
Start date: 2009-01-01, End date: 2013-12-31
