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 BACEMO
Project Bacterial Cell Morphogenesis
Researcher (PI) Rut Carballido Lopez
Host Institution (HI) INSTITUT NATIONAL DE RECHERCHE POUR L'AGRICULTURE, L'ALIMENTATION ET L'ENVIRONNEMENT
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary In bacteria, the though external cell wall and the intracellular actin-like (MreB) cytoskeleton are major determinants of cell shape. The biosynthetic pathways and chemical composition of the cell wall, a three dimensional polymer network that is one of the most prominent targets for antibiotics, are well understood. However, despite decades of study, little is known about the complex cell wall ultrastructure and the molecular mechanisms that control cell wall morphogenesis in time and space. In rod-shaped bacteria, MreB homologues assemble into dynamic structures thought to control shape by serving as organizers for the movement and assembly of macromolecular machineries that effect sidewall elongation. However, the mechanistic details used by the MreB cytoskeleton to fulfil this role remain to be elucidated. Furthermore, development of high-resolution microscopy techniques has led to new breakthroughs this year, published by our lab and others, which are shaking the model developed over the last decade and re-questioning the MreB “actin cytoskeleton” designation.
The aim of this project is to combine powerful genetic, biochemical, genomic and systems biology approaches available in the model bacterium Bacillus subtilis with modern high-resolution light microscopic techniques to study the dynamics and mechanistic details of the MreB cytoskeleton and of CW assembly. Parameters measured by the different approaches will be combined to quantitatively describe the features of bacterial cell morphogenesis.
Summary
In bacteria, the though external cell wall and the intracellular actin-like (MreB) cytoskeleton are major determinants of cell shape. The biosynthetic pathways and chemical composition of the cell wall, a three dimensional polymer network that is one of the most prominent targets for antibiotics, are well understood. However, despite decades of study, little is known about the complex cell wall ultrastructure and the molecular mechanisms that control cell wall morphogenesis in time and space. In rod-shaped bacteria, MreB homologues assemble into dynamic structures thought to control shape by serving as organizers for the movement and assembly of macromolecular machineries that effect sidewall elongation. However, the mechanistic details used by the MreB cytoskeleton to fulfil this role remain to be elucidated. Furthermore, development of high-resolution microscopy techniques has led to new breakthroughs this year, published by our lab and others, which are shaking the model developed over the last decade and re-questioning the MreB “actin cytoskeleton” designation.
The aim of this project is to combine powerful genetic, biochemical, genomic and systems biology approaches available in the model bacterium Bacillus subtilis with modern high-resolution light microscopic techniques to study the dynamics and mechanistic details of the MreB cytoskeleton and of CW assembly. Parameters measured by the different approaches will be combined to quantitatively describe the features of bacterial cell morphogenesis.
Max ERC Funding
1 650 050 €
Duration
Start date: 2013-02-01, End date: 2019-01-31
Project acronym BIOMECAMORPH
Project The Biomechanics of Epithelial Cell and Tissue Morphogenesis
Researcher (PI) Thomas Marie Michel Lecuit
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary Tissue morphogenesis is a complex process that emerges from spatially controlled patterns of cell shape changes. Dedicated genetic programmes regulate cell behaviours, exemplified in animals by the specification of apical constriction in invaginating epithelial tissues, or the orientation of cell intercalation during tissue extension. This genetic control is constrained by physical properties of cells that dictate how they can modify their shape. A major challenge is to understand how biochemical pathways control subcellular mechanics in epithelia, such as how forces are produced by interactions between actin filaments and myosin motors, and how these forces are transmitted at cell junctions. The major objective of our project is to investigate the fundamental principles of epithelial mechanics and to understand how intercellular signals and mechanical coupling between cells coordinate individual behaviours at the tissue level.
We will study early Drosophila embryogenesis and combine quantitative cell biological studies of cell dynamics, biophysical characterization of cell mechanics and genetic control of cell signalling to answer the following questions: i) how are forces generated, in particular what underlies deformation and stabilization of cell shape by actomyosin networks, and pulsatile contractility; ii) how are forces transmitted at junctions, what are the feedback interactions between tension generation and transmission; iii) how are individual cell mechanics orchestrated at the tissue level to yield collective tissue morphogenesis?
We expect to encapsulate the information-based, cell biological and physical descriptions of morphogenesis in a single, coherent framework. The project should impact more broadly on morphogenesis in other organisms and shed light on the mechanisms underlying robustness and plasticity in epithelia.
Summary
Tissue morphogenesis is a complex process that emerges from spatially controlled patterns of cell shape changes. Dedicated genetic programmes regulate cell behaviours, exemplified in animals by the specification of apical constriction in invaginating epithelial tissues, or the orientation of cell intercalation during tissue extension. This genetic control is constrained by physical properties of cells that dictate how they can modify their shape. A major challenge is to understand how biochemical pathways control subcellular mechanics in epithelia, such as how forces are produced by interactions between actin filaments and myosin motors, and how these forces are transmitted at cell junctions. The major objective of our project is to investigate the fundamental principles of epithelial mechanics and to understand how intercellular signals and mechanical coupling between cells coordinate individual behaviours at the tissue level.
We will study early Drosophila embryogenesis and combine quantitative cell biological studies of cell dynamics, biophysical characterization of cell mechanics and genetic control of cell signalling to answer the following questions: i) how are forces generated, in particular what underlies deformation and stabilization of cell shape by actomyosin networks, and pulsatile contractility; ii) how are forces transmitted at junctions, what are the feedback interactions between tension generation and transmission; iii) how are individual cell mechanics orchestrated at the tissue level to yield collective tissue morphogenesis?
We expect to encapsulate the information-based, cell biological and physical descriptions of morphogenesis in a single, coherent framework. The project should impact more broadly on morphogenesis in other organisms and shed light on the mechanisms underlying robustness and plasticity in epithelia.
Max ERC Funding
2 473 313 €
Duration
Start date: 2013-05-01, End date: 2018-04-30
Project acronym CarnoMorph
Project The Evolution and Development of Complex Morphologies
Researcher (PI) Enrico Coen
Host Institution (HI) JOHN INNES CENTRE
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary Plant and animal organs display a remarkable diversity of shapes. A major challenge in developmental and evolutionary biology is to understand how this diversity of forms is generated. Recent advances in imaging, computational modelling and genomics now make it possible to address this challenge effectively for the first time. Leaf development is a particularly tractable system because of its accessibility to imaging and preservation of connectivity during growth. Leaves also display remarkable diversity in shape and form, with perhaps the most complex form being the pitcher-shaped (epiascidiate) leaves of carnivorous plants. This form has evolved four times independently, raising the question of whether its seeming complexity may have arisen through simple modulations in underlying morphogenetic mechanisms. To test this hypothesis, I aim to develop a model system for carnivorous plants based on Utricularia gibba (humped bladderwort), which has the advantage of having one of the smallest genomes known in plants (~2/3 the size of the Arabidopsis genome) and small transparent pitcher-shaped leaves amenable to imaging. I will use this system to define the morphogenetic events underlying the formation of pitcher-shaped leaves and their molecular genetic control. I will also develop and apply computational modelling to explore hypotheses that may account for the development of U. gibba bladders and further test these hypotheses experimentally. In addition, I will investigate the relationship between U. gibba bladder development and species with simpler leaf shapes, such as Arabidopsis, or species where the epiascidiate form has evolved independently. Taken together, these studies should show how developmental rules elucidated in current model systems might be extended and built upon to account for the diversity and complexity of tissue forms, integrating evo-devo approaches with a mechanistic understanding of morphogenesis.
Summary
Plant and animal organs display a remarkable diversity of shapes. A major challenge in developmental and evolutionary biology is to understand how this diversity of forms is generated. Recent advances in imaging, computational modelling and genomics now make it possible to address this challenge effectively for the first time. Leaf development is a particularly tractable system because of its accessibility to imaging and preservation of connectivity during growth. Leaves also display remarkable diversity in shape and form, with perhaps the most complex form being the pitcher-shaped (epiascidiate) leaves of carnivorous plants. This form has evolved four times independently, raising the question of whether its seeming complexity may have arisen through simple modulations in underlying morphogenetic mechanisms. To test this hypothesis, I aim to develop a model system for carnivorous plants based on Utricularia gibba (humped bladderwort), which has the advantage of having one of the smallest genomes known in plants (~2/3 the size of the Arabidopsis genome) and small transparent pitcher-shaped leaves amenable to imaging. I will use this system to define the morphogenetic events underlying the formation of pitcher-shaped leaves and their molecular genetic control. I will also develop and apply computational modelling to explore hypotheses that may account for the development of U. gibba bladders and further test these hypotheses experimentally. In addition, I will investigate the relationship between U. gibba bladder development and species with simpler leaf shapes, such as Arabidopsis, or species where the epiascidiate form has evolved independently. Taken together, these studies should show how developmental rules elucidated in current model systems might be extended and built upon to account for the diversity and complexity of tissue forms, integrating evo-devo approaches with a mechanistic understanding of morphogenesis.
Max ERC Funding
2 499 997 €
Duration
Start date: 2013-06-01, End date: 2018-05-31
Project acronym ColonCan
Project Targeting downstream effectors of Wnt signaling in colorectal cancer
Researcher (PI) Owen James Sansom
Host Institution (HI) BEATSON INSTITUTE FOR CANCER RESEARCH LBG
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary Colorectal cancer (CRC) is one of the most common cancers of the western world. The underlying initiating mutation for the majority of CRC is within the Adenomatous Polyposis Coli (Apc) gene. The APC protein performs an important role in controlling the levels of Wnt signalling by targeting beta-catenin for degradation. Loss of the APC protein leads to the activation of Wnt signaling target genes such as c-Myc which is required for phenotypes causes by Apc loss.
However, despite the clear importance of APC loss and deregulated Wnt signalling, additional events are required for the development of CRC such as KRAS and P53 mutations.The impact of these changes on the development of CRC and response to therapy is not well understood. Furthermore, identification and testing of potential novel targets and therapies is hampered by lack of a preclinical model that faithfully recapitulates the course of the human disease.
This proposal has two aims:
1. Assess the impact of cooperating mutations with Apc and assess how they alter sensitivities of
Apc deficient cells.
2. Develop mouse models of invasive and metastatic colorectal cancer that recapitulate the human disease.
We will use ‘state of the art’ methodologies to identify the changes in signaling output conferred by these cooperating mutations. Genetic mouse models of invasive and metastatic colorectal cancers will be generated through the acquisition of additional mutations and genomic instability.
These studies will produce predictions on therapeutic combinations that will be tested in mouse models in vitro and in vivo that may identify new treatment regimens for patients with late stage CRC.
Summary
Colorectal cancer (CRC) is one of the most common cancers of the western world. The underlying initiating mutation for the majority of CRC is within the Adenomatous Polyposis Coli (Apc) gene. The APC protein performs an important role in controlling the levels of Wnt signalling by targeting beta-catenin for degradation. Loss of the APC protein leads to the activation of Wnt signaling target genes such as c-Myc which is required for phenotypes causes by Apc loss.
However, despite the clear importance of APC loss and deregulated Wnt signalling, additional events are required for the development of CRC such as KRAS and P53 mutations.The impact of these changes on the development of CRC and response to therapy is not well understood. Furthermore, identification and testing of potential novel targets and therapies is hampered by lack of a preclinical model that faithfully recapitulates the course of the human disease.
This proposal has two aims:
1. Assess the impact of cooperating mutations with Apc and assess how they alter sensitivities of
Apc deficient cells.
2. Develop mouse models of invasive and metastatic colorectal cancer that recapitulate the human disease.
We will use ‘state of the art’ methodologies to identify the changes in signaling output conferred by these cooperating mutations. Genetic mouse models of invasive and metastatic colorectal cancers will be generated through the acquisition of additional mutations and genomic instability.
These studies will produce predictions on therapeutic combinations that will be tested in mouse models in vitro and in vivo that may identify new treatment regimens for patients with late stage CRC.
Max ERC Funding
1 499 045 €
Duration
Start date: 2012-11-01, End date: 2017-10-31
Project acronym DEATHSWITCHING
Project Identifying genes and pathways that drive molecular switches and back-up mechanisms between apoptosis and autophagy
Researcher (PI) Adi Kimchi
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary A cell’s decision to die is governed by multiple input signals received from a complex network of programmed cell death (PCD) pathways, including apoptosis and programmed necrosis. Additionally, under some conditions, autophagy, whose function is mainly pro-survival, may act as a back-up death pathway. We propose to apply new approaches to study the molecular basis of two important questions that await resolution in the field: a) how the cell switches from a pro-survival autophagic response to an apoptotic response and b) whether and how pro-survival autophagy is converted to a death mechanism when apoptosis is blocked. To address the first issue, we will screen for direct physical interactions between autophagic and apoptotic proteins, using the protein fragment complementation assay. Validated pairs will be studied in depth to identify built-in molecular switches that activate apoptosis when autophagy fails to restore homeostasis. As a pilot case to address the concept of molecular ‘sensors’ and ‘switches’, we will focus on the previously identified Atg12/Bcl-2 interaction. In the second line of research we will categorize autophagy-dependent cell death triggers into those that directly result from autophagy-dependent degradation, either by excessive self-digestion or by selective protein degradation, and those that utilize the autophagy machinery to activate programmed necrosis. We will identify the genes regulating these scenarios by whole genome RNAi screens for increased cell survival. In parallel, we will use a cell library of annotated fluorescent-tagged proteins for measuring selective protein degradation. These will be the starting point for identification of the molecular pathways that convert survival autophagy to a death program. Finally, we will explore the physiological relevance of back-up death mechanisms and the newly identified molecular mechanisms to developmental PCD during the cavitation process in early stages of embryogenesis.
Summary
A cell’s decision to die is governed by multiple input signals received from a complex network of programmed cell death (PCD) pathways, including apoptosis and programmed necrosis. Additionally, under some conditions, autophagy, whose function is mainly pro-survival, may act as a back-up death pathway. We propose to apply new approaches to study the molecular basis of two important questions that await resolution in the field: a) how the cell switches from a pro-survival autophagic response to an apoptotic response and b) whether and how pro-survival autophagy is converted to a death mechanism when apoptosis is blocked. To address the first issue, we will screen for direct physical interactions between autophagic and apoptotic proteins, using the protein fragment complementation assay. Validated pairs will be studied in depth to identify built-in molecular switches that activate apoptosis when autophagy fails to restore homeostasis. As a pilot case to address the concept of molecular ‘sensors’ and ‘switches’, we will focus on the previously identified Atg12/Bcl-2 interaction. In the second line of research we will categorize autophagy-dependent cell death triggers into those that directly result from autophagy-dependent degradation, either by excessive self-digestion or by selective protein degradation, and those that utilize the autophagy machinery to activate programmed necrosis. We will identify the genes regulating these scenarios by whole genome RNAi screens for increased cell survival. In parallel, we will use a cell library of annotated fluorescent-tagged proteins for measuring selective protein degradation. These will be the starting point for identification of the molecular pathways that convert survival autophagy to a death program. Finally, we will explore the physiological relevance of back-up death mechanisms and the newly identified molecular mechanisms to developmental PCD during the cavitation process in early stages of embryogenesis.
Max ERC Funding
2 500 000 €
Duration
Start date: 2013-03-01, End date: 2018-02-28
Project acronym DIVISIONPLANESWITCH
Project Control mechanisms that pattern microtubules for switching cell division planes during plant morphogenesis
Researcher (PI) Pankaj Bacharam Dhonukshe
Host Institution (HI) VIB VZW
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary Oriented cell divisions dictate morphogenesis by shaping tissues and organs of multicellular organisms. Oriented cell divisions have profound influence in plants because their cell positions are locked by shared cell walls. A relay of cell divisions involving precise division plane switches determines embryonic body plan, organ layout and organ architecture in plants. Cell division planes in plants are specified by reorganization of premitotic cortical microtubule array and how this occurs is a long-standing key question.
My recent results establish, for the first time in plants, an in vivo inducible and traceable, precise 90º cell division plane switch system. With this system I identified a pathway that proceeds from transcriptional activation through a signaling module all the way to the activation of microtubule regulators that orchestrate switches in premitotic microtubule organization and cell division planes. My findings provide a first paradigm in plants of how genetic circuitry patterns cell division planes via feeding onto cellular machinery and pave the way for unraveling mechanistic control of cell division plane switch.
By establishing a precise cell division plane switch system I am in a unique position to answer:
1. What transcriptional program and molecular players control premitotic microtubule reorganization?
2. Which mechanisms switch premitotic microtubule array?
3. What influence do identified players and mechanisms have on different types of oriented cell divisions in plants?
For this I propose a systematic research plan combining (i) forward genetics and expression profile screens for identifying a suite of microtubule regulators, (ii) state-of-the-art microscopy and modeling approaches for uncovering mechanisms of their actions and (iii) their tissue-specific manipulations to modify plant form.
By unraveling players and mechanisms this proposal shall resolve regulation of oriented cell divisions and expand plant engineering toolbox.
Summary
Oriented cell divisions dictate morphogenesis by shaping tissues and organs of multicellular organisms. Oriented cell divisions have profound influence in plants because their cell positions are locked by shared cell walls. A relay of cell divisions involving precise division plane switches determines embryonic body plan, organ layout and organ architecture in plants. Cell division planes in plants are specified by reorganization of premitotic cortical microtubule array and how this occurs is a long-standing key question.
My recent results establish, for the first time in plants, an in vivo inducible and traceable, precise 90º cell division plane switch system. With this system I identified a pathway that proceeds from transcriptional activation through a signaling module all the way to the activation of microtubule regulators that orchestrate switches in premitotic microtubule organization and cell division planes. My findings provide a first paradigm in plants of how genetic circuitry patterns cell division planes via feeding onto cellular machinery and pave the way for unraveling mechanistic control of cell division plane switch.
By establishing a precise cell division plane switch system I am in a unique position to answer:
1. What transcriptional program and molecular players control premitotic microtubule reorganization?
2. Which mechanisms switch premitotic microtubule array?
3. What influence do identified players and mechanisms have on different types of oriented cell divisions in plants?
For this I propose a systematic research plan combining (i) forward genetics and expression profile screens for identifying a suite of microtubule regulators, (ii) state-of-the-art microscopy and modeling approaches for uncovering mechanisms of their actions and (iii) their tissue-specific manipulations to modify plant form.
By unraveling players and mechanisms this proposal shall resolve regulation of oriented cell divisions and expand plant engineering toolbox.
Max ERC Funding
1 500 000 €
Duration
Start date: 2013-01-01, End date: 2017-12-31
Project acronym DROPFAT
Project Biogenesis of lipid droplets and lipid homeostasis
Researcher (PI) Pedro Nuno Chaves Simoes De Carvalho
Host Institution (HI) THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary Organisms and cells face a myriad of environmental changes with periods of nutrient surplus and shortage. It is therefore not surprising that in all kingdoms of life, cells have evolved the means to store energy and thereby minimize the effects of environmental fluctuations. While the capability for energy storage has obvious advantages, deregulated energy accumulation can also be detrimental and is the hallmark of many diseases such as obesity.
In most cells energy is stored as neutral lipids in a dedicated cellular compartment, the lipid droplets (LDs). LDs are found in virtually every eukaryotic cell and play a central role in cellular lipid and energy metabolism. Despite their ubiquitous presence and importance, the physiology of LDs is poorly understood. LDs are composed of a single lipid layer and therefore distinct from all other cellular compartments. How do LDs originate at the endoplasmic reticulum (ER) and what is the machinery involved? How is the size, number and the storage capacity of the LDs regulated? How are specific proteins and lipids targeted to LDs? Addressing these questions is fundamental for understanding the “life cycle” of LDs and for a global picture of the cellular energy homeostasis.
The main goal of this proposal is to reveal the molecular mechanisms controlling neutral lipid dynamics and their storage in LDs. We will focus specifically on the role of the endoplasmic reticulum in the biogenesis of LDs. First, we will identify the ER protein complexes required for LD formation and regulation. Second, we will develop an assay to dissect the targeting of proteins to LDs. Finally, we will develop a cell-free system that recapitulates the biogenesis of LDs in vitro. Altogether, our strategy constitutes a systematic, in-depth analysis of LD dynamics and will lead to significant insight on the mechanisms of cellular energy storage. Our findings will likely offer a better understanding of human pathologies such as obesity and lipodistrophies
Summary
Organisms and cells face a myriad of environmental changes with periods of nutrient surplus and shortage. It is therefore not surprising that in all kingdoms of life, cells have evolved the means to store energy and thereby minimize the effects of environmental fluctuations. While the capability for energy storage has obvious advantages, deregulated energy accumulation can also be detrimental and is the hallmark of many diseases such as obesity.
In most cells energy is stored as neutral lipids in a dedicated cellular compartment, the lipid droplets (LDs). LDs are found in virtually every eukaryotic cell and play a central role in cellular lipid and energy metabolism. Despite their ubiquitous presence and importance, the physiology of LDs is poorly understood. LDs are composed of a single lipid layer and therefore distinct from all other cellular compartments. How do LDs originate at the endoplasmic reticulum (ER) and what is the machinery involved? How is the size, number and the storage capacity of the LDs regulated? How are specific proteins and lipids targeted to LDs? Addressing these questions is fundamental for understanding the “life cycle” of LDs and for a global picture of the cellular energy homeostasis.
The main goal of this proposal is to reveal the molecular mechanisms controlling neutral lipid dynamics and their storage in LDs. We will focus specifically on the role of the endoplasmic reticulum in the biogenesis of LDs. First, we will identify the ER protein complexes required for LD formation and regulation. Second, we will develop an assay to dissect the targeting of proteins to LDs. Finally, we will develop a cell-free system that recapitulates the biogenesis of LDs in vitro. Altogether, our strategy constitutes a systematic, in-depth analysis of LD dynamics and will lead to significant insight on the mechanisms of cellular energy storage. Our findings will likely offer a better understanding of human pathologies such as obesity and lipodistrophies
Max ERC Funding
1 475 282 €
Duration
Start date: 2013-02-01, End date: 2018-01-31
Project acronym EMTASY
Project Common molecular pathways in epithelial-mesenchymal transition and left-right asymmetries
Researcher (PI) Maria Angela Nieto Toledano
Host Institution (HI) AGENCIA ESTATAL CONSEJO SUPERIOR DEINVESTIGACIONES CIENTIFICAS
Call Details Advanced Grant (AdG), LS3, ERC-2012-ADG_20120314
Summary The majority of animals show an external bilateral symmetry, precluding the observation of multiple internal left-right (L/R) asymmetries which are fundamental for organ packaging and function. A prominent molecular pathway converging on and downstream of the Pitx2 transcription factor confers left-handed information in the left side of the embryo, with players expressed on the right ensuring that the left determinants are excluded. Therefore, conferring or excluding left identity in left and right hand sides, respectively, drives L/R asymmetry. Some indications suggest that a program actively specifying right–handed information could exist on the right. Our recent findings support this view. In a screening for novel regulators of the epithelial to mesenchymal transition (EMT), we have identified a transcription factor, EMT2, which similarly to well known factor Snail, it is an EMT inducer. The EMT is crucial for the development of tissues during embryonic development and for the progression of carcinomas to the invasive state. Strikingly, again as Snail, in addition to promote EMT, the EMT2 factor is predominantly expressed on the right side and may operate instructing L/R identity on the right-hand side of the embryo.
With this background, our knowledge of the EMT and a series of genome-wide high-throughput approaches and a comprehensive functional analysis using the chick, the fish and the mouse as model systems we propose to reveal the putative molecular pathways conveying right-handed information and to reveal commonalities between L/R pathways and the EMT. In the long run, we aim at better understanding human pathologies that involve these morphogenetic and cellular processes, including pathological situs conditions (i.e. altered organ positioning) and cancer progression.
Summary
The majority of animals show an external bilateral symmetry, precluding the observation of multiple internal left-right (L/R) asymmetries which are fundamental for organ packaging and function. A prominent molecular pathway converging on and downstream of the Pitx2 transcription factor confers left-handed information in the left side of the embryo, with players expressed on the right ensuring that the left determinants are excluded. Therefore, conferring or excluding left identity in left and right hand sides, respectively, drives L/R asymmetry. Some indications suggest that a program actively specifying right–handed information could exist on the right. Our recent findings support this view. In a screening for novel regulators of the epithelial to mesenchymal transition (EMT), we have identified a transcription factor, EMT2, which similarly to well known factor Snail, it is an EMT inducer. The EMT is crucial for the development of tissues during embryonic development and for the progression of carcinomas to the invasive state. Strikingly, again as Snail, in addition to promote EMT, the EMT2 factor is predominantly expressed on the right side and may operate instructing L/R identity on the right-hand side of the embryo.
With this background, our knowledge of the EMT and a series of genome-wide high-throughput approaches and a comprehensive functional analysis using the chick, the fish and the mouse as model systems we propose to reveal the putative molecular pathways conveying right-handed information and to reveal commonalities between L/R pathways and the EMT. In the long run, we aim at better understanding human pathologies that involve these morphogenetic and cellular processes, including pathological situs conditions (i.e. altered organ positioning) and cancer progression.
Max ERC Funding
2 460 000 €
Duration
Start date: 2013-05-01, End date: 2018-12-31
Project acronym EUROPolYps
Project Identity and functions of polyphosphate polymerases in eukaryotes
Researcher (PI) Michael Hothorn
Host Institution (HI) UNIVERSITE DE GENEVE
Call Details Starting Grant (StG), LS3, ERC-2012-StG_20111109
Summary Inorganic polyphosphate (polyP), a linear polymer of dozens to thousands of orthophosphate units, has been found in virtually every pro- and eukaryotic cell. PolyP regulates blood clotting, inflammation and bone formation in humans, symbiotic interactions in plants and stress responses in bacteria. The molecular functions of this high-energy polymer however remain largely enigmatic and its synthesis has only been characterized in prokaryotes. Systematic investigation of polyP functions in higher organisms has so far been hampered by our complete lack of knowledge about the molecular machinery required for polyP synthesis, transport, storage and signalling. Here, I propose a multi-disciplinary approach to dissect the origins and functions of polyP in eukaryotes. Using a candidate approach, I have identified the polyP polymerase in Arabidopsis thaliana, and a closely related human enzyme. I propose to dissect the architecture and catalytic mechanism of the plant polyphosphate polymerase, and study its distribution in cells and tissues. Using genetics, we will next analyse the contribution of polyP synthesis to plant metabolism, growth and development. In parallel, we will develop biosensors to visualize the transport, storage and re-mobilisation of polyP in living cells. Together, these experiments should yield traceable phenotypes and novel tools that will enable us for the first time to design and evaluate polyP-specific genetic screens. By this means, we hope to identify other players involved in polyP metabolism, transport, storage, re-mobilisation and signalling. We will translate our findings from Arabidopsis to animal models, and study the evolution of this ancient polymer. I envision that our work will uncover a fundamental metabolic pathway, and may spur the design of crops that require less phosphate fertilizer, small molecule inhibitors against human parasites, and novel drugs that target inflammatory disease and osteoporosis.
Summary
Inorganic polyphosphate (polyP), a linear polymer of dozens to thousands of orthophosphate units, has been found in virtually every pro- and eukaryotic cell. PolyP regulates blood clotting, inflammation and bone formation in humans, symbiotic interactions in plants and stress responses in bacteria. The molecular functions of this high-energy polymer however remain largely enigmatic and its synthesis has only been characterized in prokaryotes. Systematic investigation of polyP functions in higher organisms has so far been hampered by our complete lack of knowledge about the molecular machinery required for polyP synthesis, transport, storage and signalling. Here, I propose a multi-disciplinary approach to dissect the origins and functions of polyP in eukaryotes. Using a candidate approach, I have identified the polyP polymerase in Arabidopsis thaliana, and a closely related human enzyme. I propose to dissect the architecture and catalytic mechanism of the plant polyphosphate polymerase, and study its distribution in cells and tissues. Using genetics, we will next analyse the contribution of polyP synthesis to plant metabolism, growth and development. In parallel, we will develop biosensors to visualize the transport, storage and re-mobilisation of polyP in living cells. Together, these experiments should yield traceable phenotypes and novel tools that will enable us for the first time to design and evaluate polyP-specific genetic screens. By this means, we hope to identify other players involved in polyP metabolism, transport, storage, re-mobilisation and signalling. We will translate our findings from Arabidopsis to animal models, and study the evolution of this ancient polymer. I envision that our work will uncover a fundamental metabolic pathway, and may spur the design of crops that require less phosphate fertilizer, small molecule inhibitors against human parasites, and novel drugs that target inflammatory disease and osteoporosis.
Max ERC Funding
1 434 822 €
Duration
Start date: 2013-01-01, End date: 2017-12-31
