Project acronym 20SComplexity
Project An integrative approach to uncover the multilevel regulation of 20S proteasome degradation
Researcher (PI) Michal Sharon
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS1, ERC-2014-STG
Summary For many years, the ubiquitin-26S proteasome degradation pathway was considered the primary route for proteasomal degradation. However, it is now becoming clear that proteins can also be targeted for degradation by a ubiquitin-independent mechanism mediated by the core 20S proteasome itself. Although initially believed to be limited to rare exceptions, degradation by the 20S proteasome is now understood to have a wide range of substrates, many of which are key regulatory proteins. Despite its importance, little is known about the mechanisms that control 20S proteasomal degradation, unlike the extensive knowledge acquired over the years concerning degradation by the 26S proteasome. Our overall aim is to reveal the multiple regulatory levels that coordinate the 20S proteasome degradation route.
To achieve this goal we will carry out a comprehensive research program characterizing three distinct levels of 20S proteasome regulation:
Intra-molecular regulation- Revealing the intrinsic molecular switch that activates the latent 20S proteasome.
Inter-molecular regulation- Identifying novel proteins that bind the 20S proteasome to regulate its activity and characterizing their mechanism of function.
Cellular regulatory networks- Unraveling the cellular cues and multiple pathways that influence 20S proteasome activity using a novel systematic and unbiased screening approach.
Our experimental strategy involves the combination of biochemical approaches with native mass spectrometry, cross-linking and fluorescence measurements, complemented by cell biology analyses and high-throughput screening. Such a multidisciplinary approach, integrating in vitro and in vivo findings, will likely provide the much needed knowledge on the 20S proteasome degradation route. When completed, we anticipate that this work will be part of a new paradigm – no longer perceiving the 20S proteasome mediated degradation as a simple and passive event but rather a tightly regulated and coordinated process.
Summary
For many years, the ubiquitin-26S proteasome degradation pathway was considered the primary route for proteasomal degradation. However, it is now becoming clear that proteins can also be targeted for degradation by a ubiquitin-independent mechanism mediated by the core 20S proteasome itself. Although initially believed to be limited to rare exceptions, degradation by the 20S proteasome is now understood to have a wide range of substrates, many of which are key regulatory proteins. Despite its importance, little is known about the mechanisms that control 20S proteasomal degradation, unlike the extensive knowledge acquired over the years concerning degradation by the 26S proteasome. Our overall aim is to reveal the multiple regulatory levels that coordinate the 20S proteasome degradation route.
To achieve this goal we will carry out a comprehensive research program characterizing three distinct levels of 20S proteasome regulation:
Intra-molecular regulation- Revealing the intrinsic molecular switch that activates the latent 20S proteasome.
Inter-molecular regulation- Identifying novel proteins that bind the 20S proteasome to regulate its activity and characterizing their mechanism of function.
Cellular regulatory networks- Unraveling the cellular cues and multiple pathways that influence 20S proteasome activity using a novel systematic and unbiased screening approach.
Our experimental strategy involves the combination of biochemical approaches with native mass spectrometry, cross-linking and fluorescence measurements, complemented by cell biology analyses and high-throughput screening. Such a multidisciplinary approach, integrating in vitro and in vivo findings, will likely provide the much needed knowledge on the 20S proteasome degradation route. When completed, we anticipate that this work will be part of a new paradigm – no longer perceiving the 20S proteasome mediated degradation as a simple and passive event but rather a tightly regulated and coordinated process.
Max ERC Funding
1 500 000 €
Duration
Start date: 2015-04-01, End date: 2020-03-31
Project acronym ABDESIGN
Project Computational design of novel protein function in antibodies
Researcher (PI) Sarel-Jacob Fleishman
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Starting Grant (StG), LS1, ERC-2013-StG
Summary We propose to elucidate the structural design principles of naturally occurring antibody complementarity-determining regions (CDRs) and to computationally design novel antibody functions. Antibodies represent the most versatile known system for molecular recognition. Research has yielded many insights into antibody design principles and promising biotechnological and pharmaceutical applications. Still, our understanding of how CDRs encode specific loop conformations lags far behind our understanding of structure-function relationships in non-immunological scaffolds. Thus, design of antibodies from first principles has not been demonstrated. We propose a computational-experimental strategy to address this challenge. We will: (a) characterize the design principles and sequence elements that rigidify antibody CDRs. Natural antibody loops will be subjected to computational modeling, crystallography, and a combined in vitro evolution and deep-sequencing approach to isolate sequence features that rigidify loop backbones; (b) develop a novel computational-design strategy, which uses the >1000 solved structures of antibodies deposited in structure databases to realistically model CDRs and design them to recognize proteins that have not been co-crystallized with antibodies. For example, we will design novel antibodies targeting insulin, for which clinically useful diagnostics are needed. By accessing much larger sequence/structure spaces than are available to natural immune-system repertoires and experimental methods, computational antibody design could produce higher-specificity and higher-affinity binders, even to challenging targets; and (c) develop new strategies to program conformational change in CDRs, generating, e.g., the first allosteric antibodies. These will allow targeting, in principle, of any molecule, potentially revolutionizing how antibodies are generated for research and medicine, providing new insights on the design principles of protein functional sites.
Summary
We propose to elucidate the structural design principles of naturally occurring antibody complementarity-determining regions (CDRs) and to computationally design novel antibody functions. Antibodies represent the most versatile known system for molecular recognition. Research has yielded many insights into antibody design principles and promising biotechnological and pharmaceutical applications. Still, our understanding of how CDRs encode specific loop conformations lags far behind our understanding of structure-function relationships in non-immunological scaffolds. Thus, design of antibodies from first principles has not been demonstrated. We propose a computational-experimental strategy to address this challenge. We will: (a) characterize the design principles and sequence elements that rigidify antibody CDRs. Natural antibody loops will be subjected to computational modeling, crystallography, and a combined in vitro evolution and deep-sequencing approach to isolate sequence features that rigidify loop backbones; (b) develop a novel computational-design strategy, which uses the >1000 solved structures of antibodies deposited in structure databases to realistically model CDRs and design them to recognize proteins that have not been co-crystallized with antibodies. For example, we will design novel antibodies targeting insulin, for which clinically useful diagnostics are needed. By accessing much larger sequence/structure spaces than are available to natural immune-system repertoires and experimental methods, computational antibody design could produce higher-specificity and higher-affinity binders, even to challenging targets; and (c) develop new strategies to program conformational change in CDRs, generating, e.g., the first allosteric antibodies. These will allow targeting, in principle, of any molecule, potentially revolutionizing how antibodies are generated for research and medicine, providing new insights on the design principles of protein functional sites.
Max ERC Funding
1 499 930 €
Duration
Start date: 2013-09-01, End date: 2018-08-31
Project acronym ACCENT
Project Unravelling the architecture and the cartography of the human centriole
Researcher (PI) Paul, Philippe, Desiré GUICHARD
Host Institution (HI) UNIVERSITE DE GENEVE
Call Details Starting Grant (StG), LS1, ERC-2016-STG
Summary The centriole is the largest evolutionary conserved macromolecular structure responsible for building centrosomes and cilia or flagella in many eukaryotes. Centrioles are critical for the proper execution of important biological processes ranging from cell division to cell signaling. Moreover, centriolar defects have been associated to several human pathologies including ciliopathies and cancer. This state of facts emphasizes the importance of understanding centriole biogenesis. The study of centriole formation is a deep-rooted question, however our current knowledge on its molecular organization at high resolution remains fragmented and limited. In particular, exquisite details of the overall molecular architecture of the human centriole and in particular of its central core region are lacking to understand the basis of centriole organization and function. Resolving this important question represents a challenge that needs to be undertaken and will undoubtedly lead to groundbreaking advances. Another important question to tackle next is to develop innovative methods to enable the nanometric molecular mapping of centriolar proteins within distinct architectural elements of the centriole. This missing information will be key to unravel the molecular mechanisms behind centriolar organization.
This research proposal aims at building a cartography of the human centriole by elucidating its molecular composition and architecture. To this end, we will combine the use of innovative and multidisciplinary techniques encompassing spatial proteomics, cryo-electron tomography, state-of-the-art microscopy and in vitro assays and to achieve a comprehensive molecular and structural view of the human centriole. All together, we expect that these advances will help understand basic principles underlying centriole and cilia formation as well as might have further relevance for human health.
Summary
The centriole is the largest evolutionary conserved macromolecular structure responsible for building centrosomes and cilia or flagella in many eukaryotes. Centrioles are critical for the proper execution of important biological processes ranging from cell division to cell signaling. Moreover, centriolar defects have been associated to several human pathologies including ciliopathies and cancer. This state of facts emphasizes the importance of understanding centriole biogenesis. The study of centriole formation is a deep-rooted question, however our current knowledge on its molecular organization at high resolution remains fragmented and limited. In particular, exquisite details of the overall molecular architecture of the human centriole and in particular of its central core region are lacking to understand the basis of centriole organization and function. Resolving this important question represents a challenge that needs to be undertaken and will undoubtedly lead to groundbreaking advances. Another important question to tackle next is to develop innovative methods to enable the nanometric molecular mapping of centriolar proteins within distinct architectural elements of the centriole. This missing information will be key to unravel the molecular mechanisms behind centriolar organization.
This research proposal aims at building a cartography of the human centriole by elucidating its molecular composition and architecture. To this end, we will combine the use of innovative and multidisciplinary techniques encompassing spatial proteomics, cryo-electron tomography, state-of-the-art microscopy and in vitro assays and to achieve a comprehensive molecular and structural view of the human centriole. All together, we expect that these advances will help understand basic principles underlying centriole and cilia formation as well as might have further relevance for human health.
Max ERC Funding
1 498 965 €
Duration
Start date: 2017-01-01, End date: 2021-12-31
Project acronym AGALT
Project Asymptotic Geometric Analysis and Learning Theory
Researcher (PI) Shahar Mendelson
Host Institution (HI) TECHNION - ISRAEL INSTITUTE OF TECHNOLOGY
Call Details Starting Grant (StG), PE1, ERC-2007-StG
Summary In a typical learning problem one tries to approximate an unknown function by a function from a given class using random data, sampled according to an unknown measure. In this project we will be interested in parameters that govern the complexity of a learning problem. It turns out that this complexity is determined by the geometry of certain sets in high dimension that are connected to the given class (random coordinate projections of the class). Thus, one has to understand the structure of these sets as a function of the dimension - which is given by the cardinality of the random sample. The resulting analysis leads to many theoretical questions in Asymptotic Geometric Analysis, Probability (most notably, Empirical Processes Theory) and Combinatorics, which are of independent interest beyond the application to Learning Theory. Our main goal is to describe the role of various complexity parameters involved in a learning problem, to analyze the connections between them and to investigate the way they determine the geometry of the relevant high dimensional sets. Some of the questions we intend to tackle are well known open problems and making progress towards their solution will have a significant theoretical impact. Moreover, this project should lead to a more complete theory of learning and is likely to have some practical impact, for example, in the design of more efficient learning algorithms.
Summary
In a typical learning problem one tries to approximate an unknown function by a function from a given class using random data, sampled according to an unknown measure. In this project we will be interested in parameters that govern the complexity of a learning problem. It turns out that this complexity is determined by the geometry of certain sets in high dimension that are connected to the given class (random coordinate projections of the class). Thus, one has to understand the structure of these sets as a function of the dimension - which is given by the cardinality of the random sample. The resulting analysis leads to many theoretical questions in Asymptotic Geometric Analysis, Probability (most notably, Empirical Processes Theory) and Combinatorics, which are of independent interest beyond the application to Learning Theory. Our main goal is to describe the role of various complexity parameters involved in a learning problem, to analyze the connections between them and to investigate the way they determine the geometry of the relevant high dimensional sets. Some of the questions we intend to tackle are well known open problems and making progress towards their solution will have a significant theoretical impact. Moreover, this project should lead to a more complete theory of learning and is likely to have some practical impact, for example, in the design of more efficient learning algorithms.
Max ERC Funding
750 000 €
Duration
Start date: 2009-03-01, End date: 2014-02-28
Project acronym AlgTateGro
Project Constructing line bundles on algebraic varieties --around conjectures of Tate and Grothendieck
Researcher (PI) François CHARLES
Host Institution (HI) UNIVERSITE PARIS-SUD
Call Details Starting Grant (StG), PE1, ERC-2016-STG
Summary The goal of this project is to investigate two conjectures in arithmetic geometry pertaining to the geometry of projective varieties over finite and number fields. These two conjectures, formulated by Tate and Grothendieck in the 1960s, predict which cohomology classes are chern classes of line bundles. They both form an arithmetic counterpart of a theorem of Lefschetz, proved in the 1940s, which itself is the only known case of the Hodge conjecture. These two long-standing conjectures are one of the aspects of a more general web of questions regarding the topology of algebraic varieties which have been emphasized by Grothendieck and have since had a central role in modern arithmetic geometry. Special cases of these conjectures, appearing for instance in the work of Tate, Deligne, Faltings, Schneider-Lang, Masser-Wüstholz, have all had important consequences.
My goal is to investigate different lines of attack towards these conjectures, building on recent work on myself and Jean-Benoît Bost on related problems. The two main directions of the proposal are as follows. Over finite fields, the Tate conjecture is related to finiteness results for certain cohomological objects. I want to understand how to relate these to hidden boundedness properties of algebraic varieties that have appeared in my recent geometric proof of the Tate conjecture for K3 surfaces. The existence and relevance of a theory of Donaldson invariants for moduli spaces of twisted sheaves over finite fields seems to be a promising and novel direction. Over number fields, I want to combine the geometric insight above with algebraization techniques developed by Bost. In a joint project, we want to investigate how these can be used to first understand geometrically major results in transcendence theory and then attack the Grothendieck period conjecture for divisors via a number-theoretic and complex-analytic understanding of universal vector extensions of abelian schemes over curves.
Summary
The goal of this project is to investigate two conjectures in arithmetic geometry pertaining to the geometry of projective varieties over finite and number fields. These two conjectures, formulated by Tate and Grothendieck in the 1960s, predict which cohomology classes are chern classes of line bundles. They both form an arithmetic counterpart of a theorem of Lefschetz, proved in the 1940s, which itself is the only known case of the Hodge conjecture. These two long-standing conjectures are one of the aspects of a more general web of questions regarding the topology of algebraic varieties which have been emphasized by Grothendieck and have since had a central role in modern arithmetic geometry. Special cases of these conjectures, appearing for instance in the work of Tate, Deligne, Faltings, Schneider-Lang, Masser-Wüstholz, have all had important consequences.
My goal is to investigate different lines of attack towards these conjectures, building on recent work on myself and Jean-Benoît Bost on related problems. The two main directions of the proposal are as follows. Over finite fields, the Tate conjecture is related to finiteness results for certain cohomological objects. I want to understand how to relate these to hidden boundedness properties of algebraic varieties that have appeared in my recent geometric proof of the Tate conjecture for K3 surfaces. The existence and relevance of a theory of Donaldson invariants for moduli spaces of twisted sheaves over finite fields seems to be a promising and novel direction. Over number fields, I want to combine the geometric insight above with algebraization techniques developed by Bost. In a joint project, we want to investigate how these can be used to first understand geometrically major results in transcendence theory and then attack the Grothendieck period conjecture for divisors via a number-theoretic and complex-analytic understanding of universal vector extensions of abelian schemes over curves.
Max ERC Funding
1 222 329 €
Duration
Start date: 2016-12-01, End date: 2021-11-30
Project acronym altEJrepair
Project Characterisation of DNA Double-Strand Break Repair by Alternative End-Joining: Potential Targets for Cancer Therapy
Researcher (PI) Raphael CECCALDI
Host Institution (HI) INSTITUT CURIE
Call Details Starting Grant (StG), LS1, ERC-2016-STG
Summary DNA repair pathways evolved as an intricate network that senses DNA damage and resolves it in order to minimise genetic lesions and thus preventing tumour formation. Gaining in recognition the last few years, the alternative end-joining (alt-EJ) DNA repair pathway was recently shown to be up-regulated and required for cancer cell viability in the absence of homologous recombination-mediated repair (HR). Despite this integral role, the alt-EJ repair pathway remains poorly characterised in humans. As such, its molecular composition, regulation and crosstalk with HR and other repair pathways remain elusive. Additionally, the contribution of the alt-EJ pathway to tumour progression as well as the identification of a mutational signature associated with the use of alt-EJ has not yet been investigated. Moreover, the clinical relevance of developing small-molecule inhibitors targeting players in the alt-EJ pathway, such as the polymerase Pol Theta (Polθ), is of importance as current anticancer drug treatments have shown limited effectiveness in achieving cancer remission in patients with HR-deficient (HRD) tumours.
Here, we propose a novel, multidisciplinary approach that aims to characterise the players and mechanisms of action involved in the utilisation of alt-EJ in cancer. This understanding will better elucidate the changing interplay between different DNA repair pathways, thus shedding light on whether and how the use of alt-EJ contributes to the pathogenic history and survival of HRD tumours, eventually paving the way for the development of novel anticancer therapeutics.
For all the abovementioned reasons, we are convinced this project will have important implications in: 1) elucidating critical interconnections between DNA repair pathways, 2) improving the basic understanding of the composition, regulation and function of the alt-EJ pathway, and 3) facilitating the development of new synthetic lethality-based chemotherapeutics for the treatment of HRD tumours.
Summary
DNA repair pathways evolved as an intricate network that senses DNA damage and resolves it in order to minimise genetic lesions and thus preventing tumour formation. Gaining in recognition the last few years, the alternative end-joining (alt-EJ) DNA repair pathway was recently shown to be up-regulated and required for cancer cell viability in the absence of homologous recombination-mediated repair (HR). Despite this integral role, the alt-EJ repair pathway remains poorly characterised in humans. As such, its molecular composition, regulation and crosstalk with HR and other repair pathways remain elusive. Additionally, the contribution of the alt-EJ pathway to tumour progression as well as the identification of a mutational signature associated with the use of alt-EJ has not yet been investigated. Moreover, the clinical relevance of developing small-molecule inhibitors targeting players in the alt-EJ pathway, such as the polymerase Pol Theta (Polθ), is of importance as current anticancer drug treatments have shown limited effectiveness in achieving cancer remission in patients with HR-deficient (HRD) tumours.
Here, we propose a novel, multidisciplinary approach that aims to characterise the players and mechanisms of action involved in the utilisation of alt-EJ in cancer. This understanding will better elucidate the changing interplay between different DNA repair pathways, thus shedding light on whether and how the use of alt-EJ contributes to the pathogenic history and survival of HRD tumours, eventually paving the way for the development of novel anticancer therapeutics.
For all the abovementioned reasons, we are convinced this project will have important implications in: 1) elucidating critical interconnections between DNA repair pathways, 2) improving the basic understanding of the composition, regulation and function of the alt-EJ pathway, and 3) facilitating the development of new synthetic lethality-based chemotherapeutics for the treatment of HRD tumours.
Max ERC Funding
1 498 750 €
Duration
Start date: 2017-07-01, End date: 2022-06-30
Project acronym ANADEL
Project Analysis of Geometrical Effects on Dispersive Equations
Researcher (PI) Danela Oana IVANOVICI
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Starting Grant (StG), PE1, ERC-2017-STG
Summary We are concerned with localization properties of solutions to hyperbolic PDEs, especially problems with a geometric component: how do boundaries and heterogeneous media influence spreading and concentration of solutions. While our first focus is on wave and Schrödinger equations on manifolds with boundary, strong connections exist with phase space localization for (clusters of) eigenfunctions, which are of independent interest. Motivations come from nonlinear dispersive models (in physically relevant settings), properties of eigenfunctions in quantum chaos (related to both physics of optic fiber design as well as number theoretic questions), or harmonic analysis on manifolds.
Waves propagation in real life physics occur in media which are neither homogeneous or spatially infinity. The birth of radar/sonar technologies (and the raise of computed tomography) greatly motivated numerous developments in microlocal analysis and the linear theory. Only recently toy nonlinear models have been studied on a curved background, sometimes compact or rough. Understanding how to extend such tools, dealing with wave dispersion or focusing, will allow us to significantly progress in our mathematical understanding of physically relevant models. There, boundaries appear naturally and most earlier developments related to propagation of singularities in this context have limited scope with respect to crucial dispersive effects. Despite great progress over the last decade, driven by the study of quasilinear equations, our knowledge is still very limited. Going beyond this recent activity requires new tools whose development is at the heart of this proposal, including good approximate solutions (parametrices) going over arbitrarily large numbers of caustics, sharp pointwise bounds on Green functions, development of efficient wave packets methods, quantitative refinements of propagation of singularities (with direct applications in control theory), only to name a few important ones.
Summary
We are concerned with localization properties of solutions to hyperbolic PDEs, especially problems with a geometric component: how do boundaries and heterogeneous media influence spreading and concentration of solutions. While our first focus is on wave and Schrödinger equations on manifolds with boundary, strong connections exist with phase space localization for (clusters of) eigenfunctions, which are of independent interest. Motivations come from nonlinear dispersive models (in physically relevant settings), properties of eigenfunctions in quantum chaos (related to both physics of optic fiber design as well as number theoretic questions), or harmonic analysis on manifolds.
Waves propagation in real life physics occur in media which are neither homogeneous or spatially infinity. The birth of radar/sonar technologies (and the raise of computed tomography) greatly motivated numerous developments in microlocal analysis and the linear theory. Only recently toy nonlinear models have been studied on a curved background, sometimes compact or rough. Understanding how to extend such tools, dealing with wave dispersion or focusing, will allow us to significantly progress in our mathematical understanding of physically relevant models. There, boundaries appear naturally and most earlier developments related to propagation of singularities in this context have limited scope with respect to crucial dispersive effects. Despite great progress over the last decade, driven by the study of quasilinear equations, our knowledge is still very limited. Going beyond this recent activity requires new tools whose development is at the heart of this proposal, including good approximate solutions (parametrices) going over arbitrarily large numbers of caustics, sharp pointwise bounds on Green functions, development of efficient wave packets methods, quantitative refinements of propagation of singularities (with direct applications in control theory), only to name a few important ones.
Max ERC Funding
1 293 763 €
Duration
Start date: 2018-02-01, End date: 2023-01-31
Project acronym ANTIVIRNA
Project Structural and mechanistic studies of RNA-guided and RNA-targeting antiviral defense pathways
Researcher (PI) Martin Jinek
Host Institution (HI) UNIVERSITAT ZURICH
Call Details Starting Grant (StG), LS1, ERC-2013-StG
Summary The evolutionary pressures exerted by viruses on their host cells constitute a major force that drives the evolution of cellular antiviral mechanisms. The proposed research is motivated by our interest in the roles of protein-RNA interactions in both prokaryotic and eukaryotic antiviral pathways and will proceed in two directions. The first project stems from our current work on the CRISPR pathway, a recently discovered RNA-guided adaptive defense mechanism in bacteria and archaea that silences mobile genetic elements such as viruses (bacteriophages) and plasmids. CRISPR systems rely on short RNAs (crRNAs) that associate with CRISPR-associated (Cas) proteins and function as sequence-specific guides in the detection and destruction of invading nucleic acids. To obtain molecular insights into the mechanisms of crRNA-guided interference, we will pursue structural and functional studies of DNA-targeting ribonuceoprotein complexes from type II and III CRISPR systems. Our work will shed light on the function of these systems in microbial pathogenesis and provide a framework for the informed engineering of RNA-guided gene targeting technologies. The second proposed research direction centres on RNA-targeting antiviral strategies employed by the human innate immune system. Here, our work will focus on structural studies of major interferon-induced effector proteins, initially examining the allosteric activation mechanism of RNase L and subsequently focusing on other antiviral nucleases and RNA helicases, as well as mechanisms by which RNA viruses evade the innate immune response of the host. In our investigations, we plan to approach these questions using an integrated strategy combining structural biology, biochemistry and biophysics with cell-based functional studies. Together, our studies will provide fundamental molecular insights into RNA-centred antiviral mechanisms and their impact on human health and disease.
Summary
The evolutionary pressures exerted by viruses on their host cells constitute a major force that drives the evolution of cellular antiviral mechanisms. The proposed research is motivated by our interest in the roles of protein-RNA interactions in both prokaryotic and eukaryotic antiviral pathways and will proceed in two directions. The first project stems from our current work on the CRISPR pathway, a recently discovered RNA-guided adaptive defense mechanism in bacteria and archaea that silences mobile genetic elements such as viruses (bacteriophages) and plasmids. CRISPR systems rely on short RNAs (crRNAs) that associate with CRISPR-associated (Cas) proteins and function as sequence-specific guides in the detection and destruction of invading nucleic acids. To obtain molecular insights into the mechanisms of crRNA-guided interference, we will pursue structural and functional studies of DNA-targeting ribonuceoprotein complexes from type II and III CRISPR systems. Our work will shed light on the function of these systems in microbial pathogenesis and provide a framework for the informed engineering of RNA-guided gene targeting technologies. The second proposed research direction centres on RNA-targeting antiviral strategies employed by the human innate immune system. Here, our work will focus on structural studies of major interferon-induced effector proteins, initially examining the allosteric activation mechanism of RNase L and subsequently focusing on other antiviral nucleases and RNA helicases, as well as mechanisms by which RNA viruses evade the innate immune response of the host. In our investigations, we plan to approach these questions using an integrated strategy combining structural biology, biochemistry and biophysics with cell-based functional studies. Together, our studies will provide fundamental molecular insights into RNA-centred antiviral mechanisms and their impact on human health and disease.
Max ERC Funding
1 467 180 €
Duration
Start date: 2013-11-01, End date: 2018-10-31
Project acronym Autophagy in vitro
Project Reconstituting Autophagosome Biogenesis in vitro
Researcher (PI) Thomas Wollert
Host Institution (HI) INSTITUT PASTEUR
Call Details Starting Grant (StG), LS1, ERC-2014-STG
Summary Autophagy is a catabolic pathway that delivers cytoplasmic material to lysosomes for degradation. Under vegetative conditions, the pathway serves as quality control system, specifically targeting damaged or superfluous organelles and protein-aggregates. Cytotoxic stresses and starvation, however, induces the formation of larger autophagosomes that capture cargo unselectively. Autophagosomes are being generated from a cup-shaped precursor membrane, the isolation membrane, which expands to engulf cytoplasmic components. Sealing of this structure gives rise to the double-membrane surrounded autophagosomes. Two interconnected ubiquitin (Ub)-like conjugation systems coordinate the expansion of autophagosomes by conjugating the autophagy related (Atg)-protein Atg8 to the isolation membrane. In an effort to unravel the function of Atg8, we reconstituted the system on model membranes in vitro and found that Atg8 forms together with the Atg12–Atg5-Atg16 complex a membrane scaffold which is required for productive autophagy in yeast. Humans possess seven Atg8-homologs and two mutually exclusive Atg16-variants. Here, we propose to investigate the function of the human Ub-like conjugation system using a fully reconstituted in vitro system. The spatiotemporal organization of recombinant fluorescent-labeled proteins with synthetic model membranes will be investigated using confocal and TIRF-microscopy. Structural information will be obtained by atomic force and electron microscopy. Mechanistic insights, obtained from the in vitro work, will be tested in vivo in cultured human cells. We belief that revealing 1) the function of the human Ub-like conjugation system in autophagy, 2) the functional differences of Atg8-homologs and the two Atg16-variants Atg16L1 and TECPR1 and 3) how Atg16L1 coordinates non-canonical autophagy will provide essential insights into the pathophysiology of cancer, neurodegenerative, and autoimmune diseases.
Summary
Autophagy is a catabolic pathway that delivers cytoplasmic material to lysosomes for degradation. Under vegetative conditions, the pathway serves as quality control system, specifically targeting damaged or superfluous organelles and protein-aggregates. Cytotoxic stresses and starvation, however, induces the formation of larger autophagosomes that capture cargo unselectively. Autophagosomes are being generated from a cup-shaped precursor membrane, the isolation membrane, which expands to engulf cytoplasmic components. Sealing of this structure gives rise to the double-membrane surrounded autophagosomes. Two interconnected ubiquitin (Ub)-like conjugation systems coordinate the expansion of autophagosomes by conjugating the autophagy related (Atg)-protein Atg8 to the isolation membrane. In an effort to unravel the function of Atg8, we reconstituted the system on model membranes in vitro and found that Atg8 forms together with the Atg12–Atg5-Atg16 complex a membrane scaffold which is required for productive autophagy in yeast. Humans possess seven Atg8-homologs and two mutually exclusive Atg16-variants. Here, we propose to investigate the function of the human Ub-like conjugation system using a fully reconstituted in vitro system. The spatiotemporal organization of recombinant fluorescent-labeled proteins with synthetic model membranes will be investigated using confocal and TIRF-microscopy. Structural information will be obtained by atomic force and electron microscopy. Mechanistic insights, obtained from the in vitro work, will be tested in vivo in cultured human cells. We belief that revealing 1) the function of the human Ub-like conjugation system in autophagy, 2) the functional differences of Atg8-homologs and the two Atg16-variants Atg16L1 and TECPR1 and 3) how Atg16L1 coordinates non-canonical autophagy will provide essential insights into the pathophysiology of cancer, neurodegenerative, and autoimmune diseases.
Max ERC Funding
1 499 726 €
Duration
Start date: 2015-04-01, End date: 2020-03-31
Project acronym BeyondA1
Project Set theory beyond the first uncountable cardinal
Researcher (PI) Assaf Shmuel Rinot
Host Institution (HI) BAR ILAN UNIVERSITY
Call Details Starting Grant (StG), PE1, ERC-2018-STG
Summary We propose to establish a research group that will unveil the combinatorial nature of the second uncountable cardinal. This includes its Ramsey-theoretic, order-theoretic, graph-theoretic and topological features. Among others, we will be directly addressing fundamental problems due to Erdos, Rado, Galvin, and Shelah.
While some of these problems are old and well-known, an unexpected series of breakthroughs from the last three years suggest that now is a promising point in time to carry out such a project. Indeed, through a short period, four previously unattainable problems concerning the second uncountable cardinal were successfully tackled: Aspero on a club-guessing problem of Shelah, Krueger on the club-isomorphism problem for Aronszajn trees, Neeman on the isomorphism problem for dense sets of reals, and the PI on the Souslin problem. Each of these results was obtained through the development of a completely new technical framework, and these frameworks could now pave the way for the solution of some major open questions.
A goal of the highest risk in this project is the discovery of a consistent (possibly, parameterized) forcing axiom that will (preferably, simultaneously) provide structure theorems for stationary sets, linearly ordered sets, trees, graphs, and partition relations, as well as the refutation of various forms of club-guessing principles, all at the level of the second uncountable cardinal. In comparison, at the level of the first uncountable cardinal, a forcing axiom due to Foreman, Magidor and Shelah achieves exactly that.
To approach our goals, the proposed project is divided into four core areas: Uncountable trees, Ramsey theory on ordinals, Club-guessing principles, and Forcing Axioms. There is a rich bilateral interaction between any pair of the four different cores, but the proposed division will allow an efficient allocation of manpower, and will increase the chances of parallel success.
Summary
We propose to establish a research group that will unveil the combinatorial nature of the second uncountable cardinal. This includes its Ramsey-theoretic, order-theoretic, graph-theoretic and topological features. Among others, we will be directly addressing fundamental problems due to Erdos, Rado, Galvin, and Shelah.
While some of these problems are old and well-known, an unexpected series of breakthroughs from the last three years suggest that now is a promising point in time to carry out such a project. Indeed, through a short period, four previously unattainable problems concerning the second uncountable cardinal were successfully tackled: Aspero on a club-guessing problem of Shelah, Krueger on the club-isomorphism problem for Aronszajn trees, Neeman on the isomorphism problem for dense sets of reals, and the PI on the Souslin problem. Each of these results was obtained through the development of a completely new technical framework, and these frameworks could now pave the way for the solution of some major open questions.
A goal of the highest risk in this project is the discovery of a consistent (possibly, parameterized) forcing axiom that will (preferably, simultaneously) provide structure theorems for stationary sets, linearly ordered sets, trees, graphs, and partition relations, as well as the refutation of various forms of club-guessing principles, all at the level of the second uncountable cardinal. In comparison, at the level of the first uncountable cardinal, a forcing axiom due to Foreman, Magidor and Shelah achieves exactly that.
To approach our goals, the proposed project is divided into four core areas: Uncountable trees, Ramsey theory on ordinals, Club-guessing principles, and Forcing Axioms. There is a rich bilateral interaction between any pair of the four different cores, but the proposed division will allow an efficient allocation of manpower, and will increase the chances of parallel success.
Max ERC Funding
1 362 500 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
