Project acronym CENTRIOLSTRUCTNUMBER
Project Control of Centriole Structure And Number
Researcher (PI) Monica Bettencourt Carvalho Dias
Host Institution (HI) FUNDACAO CALOUSTE GULBENKIAN
Call Details Starting Grant (StG), LS3, ERC-2010-StG_20091118
Summary Centrioles are essential for the formation of several microtubule organizing structures including cilia, flagella and centrosomes. These structures are involved in a variety of functions, from cell motility to division. Centrosome defects are seen in many cancers, while abnormalities in cilia and flagella can lead to a variety of human diseases, such as polycystic kidney disease. The molecular mechanisms regulating centriole biogenesis have only recently started to be unravelled, opening new ways to answer a wide range of questions that have fascinated biologists for more than a century. In this grant we are asking two fundamental questions that are central to human disease: how is centriole structure and number established and regulated in the eukaryotic cell? To address these questions we propose to identify new molecular players, and to test the role of these and known players in the context of specific mechanistic hypothesis, using in vitro and in vivo models. We propose to develop novel assays for centriole structure and regulation in order to address mechanistic problems not accessible with today s assays. In our search for novel components we will use a multidisciplinary approach combining bioinformatics with high throughput screening. The use of in vitro systems will permit the quantitative dissection of molecular mechanisms, while the study of those mechanisms in Drosophila will allow us to understand them at the whole organism level. Furthermore, this analysis, together with studies in human tissue culture cells, will allow us to understand the consequences of misregulation of these fundamental centriole properties for human disease, such as ciliopathies and cancer. My group is already collaborating with medical doctors in the study of centriole aberrations in human disease (cancer and ciliopathies), which will be invaluable to bringing the results of this study to the translational level.
Summary
Centrioles are essential for the formation of several microtubule organizing structures including cilia, flagella and centrosomes. These structures are involved in a variety of functions, from cell motility to division. Centrosome defects are seen in many cancers, while abnormalities in cilia and flagella can lead to a variety of human diseases, such as polycystic kidney disease. The molecular mechanisms regulating centriole biogenesis have only recently started to be unravelled, opening new ways to answer a wide range of questions that have fascinated biologists for more than a century. In this grant we are asking two fundamental questions that are central to human disease: how is centriole structure and number established and regulated in the eukaryotic cell? To address these questions we propose to identify new molecular players, and to test the role of these and known players in the context of specific mechanistic hypothesis, using in vitro and in vivo models. We propose to develop novel assays for centriole structure and regulation in order to address mechanistic problems not accessible with today s assays. In our search for novel components we will use a multidisciplinary approach combining bioinformatics with high throughput screening. The use of in vitro systems will permit the quantitative dissection of molecular mechanisms, while the study of those mechanisms in Drosophila will allow us to understand them at the whole organism level. Furthermore, this analysis, together with studies in human tissue culture cells, will allow us to understand the consequences of misregulation of these fundamental centriole properties for human disease, such as ciliopathies and cancer. My group is already collaborating with medical doctors in the study of centriole aberrations in human disease (cancer and ciliopathies), which will be invaluable to bringing the results of this study to the translational level.
Max ERC Funding
1 500 000 €
Duration
Start date: 2011-01-01, End date: 2016-12-31
Project acronym PRECISE
Project Spatiotemporal regulation of chromosome segregation fidelity
Researcher (PI) Helder Jose Martins Maiato
Host Institution (HI) INSTITUTO DE BIOLOGIA MOLECULAR E CELULAR-IBMC
Call Details Starting Grant (StG), LS3, ERC-2010-StG_20091118
Summary At any given moment, 250 million cells are dividing in the human body through an essential process known as mitosis. Inaccuracy of mitosis leads directly to aneuploidy (gain or loss of chromosomes), a hallmark of several cancers and birth defects. Mitotic fidelity is controlled by the spindle assembly checkpoint (SAC), a signaling pathway that delays the progression of mitosis to ensure that all chromosomes are attached to mitotic spindle microtubules (MTs). Central to this activity, the kinetochore (KT), a minute structure on each replicated sister-chromatid, promotes the rapid turnover of MTs to correct potential attachment errors during early mitotic stages. Upon anaphase onset, the KT then switches to bind MTs with higher affinity, so that the energy derived from their depolymerizing plus ends helps driving chromosome motion to the poles. While the molecular basis of the KT-MT interface is only now starting to be elucidated, how the multiple KT activities are regulated throughout mitosis remains unknown. Here we propose to dissect from a molecular perspective how the interaction between spindle MTs and KTs controls chromosome segregation fidelity in space and time. For this purpose we will combine the power of biochemical analysis and genome-wide RNAi screens with the detailed functional investigation of already identified candidate genes using state-of-the-art live cell microscopy and pilot laser microsurgery tools in animal cells. Additionally, we have in place all the necessary conditions to investigate the physiological significance of chromosome segregation errors and evaluate respective outcomes using unique mammalian model systems. With this synergistic approach we aim to unveil the molecular routes of aneuploidygenesis and their implications to human health.
Summary
At any given moment, 250 million cells are dividing in the human body through an essential process known as mitosis. Inaccuracy of mitosis leads directly to aneuploidy (gain or loss of chromosomes), a hallmark of several cancers and birth defects. Mitotic fidelity is controlled by the spindle assembly checkpoint (SAC), a signaling pathway that delays the progression of mitosis to ensure that all chromosomes are attached to mitotic spindle microtubules (MTs). Central to this activity, the kinetochore (KT), a minute structure on each replicated sister-chromatid, promotes the rapid turnover of MTs to correct potential attachment errors during early mitotic stages. Upon anaphase onset, the KT then switches to bind MTs with higher affinity, so that the energy derived from their depolymerizing plus ends helps driving chromosome motion to the poles. While the molecular basis of the KT-MT interface is only now starting to be elucidated, how the multiple KT activities are regulated throughout mitosis remains unknown. Here we propose to dissect from a molecular perspective how the interaction between spindle MTs and KTs controls chromosome segregation fidelity in space and time. For this purpose we will combine the power of biochemical analysis and genome-wide RNAi screens with the detailed functional investigation of already identified candidate genes using state-of-the-art live cell microscopy and pilot laser microsurgery tools in animal cells. Additionally, we have in place all the necessary conditions to investigate the physiological significance of chromosome segregation errors and evaluate respective outcomes using unique mammalian model systems. With this synergistic approach we aim to unveil the molecular routes of aneuploidygenesis and their implications to human health.
Max ERC Funding
1 485 097 €
Duration
Start date: 2011-01-01, End date: 2015-12-31
Project acronym QUALIAGE
Project Spatial protein quality control and its links to aging, proteotoxicity, and polarity
Researcher (PI) Lars Bertil Thomas Nyström
Host Institution (HI) GOETEBORGS UNIVERSITET
Call Details Advanced Grant (AdG), LS3, ERC-2010-AdG_20100317
Summary Propagation of a species requires periodic cell renewal to avoid clonal senescence. My
laboratory has described a new mechanism for such cell renewal in yeast, in which damaged
protein aggregates are transported out of the daughter buds along actin cables to preserve
youthfulness. Such spatial protein quality control (SQC) is a Sir2p-dependent process and by establishing the global genetic interaction network of SIR2, we identified the
polarisome as the machinery required for mitotic segregation and translocation of protein
aggregates. In addition, we found that the fusion of smaller aggregates into large inclusion
bodies, a process that has been suggested to reduce the toxicity of such aggregates, requires
actin cables and their nucleation at the septin ring. Sir2p controls damage segregation by
affecting deacetylation and the activity of the chaperonin CCT, enhancing actin folding and
polymerization. Considering that CCT has been implicated in mitigating
aggregation/toxicity of polyglutamine proteins, e.g. huntingtin, and that actin cables is
affecting formation, fusion, and resolution of aggregates, we hypothesize that CCT
deacetylation may underlie Sirt1¿s (mammalian orthologues of Sir2p) documented beneficial
effects in several neurodegenerative disorders caused by proteotoxic aggregates. This project
is aimed at approaching this hypothesis and to elucidate, on a genome-wide scale, how the
cell tether, sort, fuse, and detoxify aggregates with the help of CCT, actin cables, and the
polarity machinery. This will be accomplished by combining the power of synthetic genetic
array analysis, high-content imaging, genome wide proximity ligand assays, and microfluidics.
Using such approaches, the project seeks to decipher the machineries of the spatial quality
control network as a means to identify new therapeutic targets that may retard or postpone
the development of age-related maladies, including neurodegenerative disorders.
Summary
Propagation of a species requires periodic cell renewal to avoid clonal senescence. My
laboratory has described a new mechanism for such cell renewal in yeast, in which damaged
protein aggregates are transported out of the daughter buds along actin cables to preserve
youthfulness. Such spatial protein quality control (SQC) is a Sir2p-dependent process and by establishing the global genetic interaction network of SIR2, we identified the
polarisome as the machinery required for mitotic segregation and translocation of protein
aggregates. In addition, we found that the fusion of smaller aggregates into large inclusion
bodies, a process that has been suggested to reduce the toxicity of such aggregates, requires
actin cables and their nucleation at the septin ring. Sir2p controls damage segregation by
affecting deacetylation and the activity of the chaperonin CCT, enhancing actin folding and
polymerization. Considering that CCT has been implicated in mitigating
aggregation/toxicity of polyglutamine proteins, e.g. huntingtin, and that actin cables is
affecting formation, fusion, and resolution of aggregates, we hypothesize that CCT
deacetylation may underlie Sirt1¿s (mammalian orthologues of Sir2p) documented beneficial
effects in several neurodegenerative disorders caused by proteotoxic aggregates. This project
is aimed at approaching this hypothesis and to elucidate, on a genome-wide scale, how the
cell tether, sort, fuse, and detoxify aggregates with the help of CCT, actin cables, and the
polarity machinery. This will be accomplished by combining the power of synthetic genetic
array analysis, high-content imaging, genome wide proximity ligand assays, and microfluidics.
Using such approaches, the project seeks to decipher the machineries of the spatial quality
control network as a means to identify new therapeutic targets that may retard or postpone
the development of age-related maladies, including neurodegenerative disorders.
Max ERC Funding
2 371 262 €
Duration
Start date: 2011-06-01, End date: 2016-05-31
