Periodic Reporting for period 5 - CentrioleBirthDeath (Mechanism of centriole inheritance and maintenance)
Periodo di rendicontazione: 2023-01-01 al 2023-06-30
Every organelle within a particular cell type has a characteristic positioning and copy number in the cell. Organelle inheritance and its persistence upon cell division, fertilisation and disease are critical questions. An essential cellular structure is the centriole, which assembles centrosomes and cilia, critical organelles for cell division, polarity, motility and signalling, often deregulated in human disease. This project investigated in an integrative and quantitative way, how centrioles are formed in the right numbers at the right time and place, and how they are maintained to ensure their function and inheritance. We first asked how centrioles guide their own assembly position (right place) and centriole copy number (right number), as well as how this process is coordinated with the cell cycle (right time). We explored critical hypotheses through a combination of biochemistry, quantitative live cell microscopy and computational modelling. Our work highlighted several properties of the system, including: i) positive and negative feedbacks and local cues; ii) how the matrix that surrounds centrioles is critical in initiating their assembly; iii) how this process can start de novo in different organisms. We also show how deregulation of those components may lead to altered centriole numbers, a phenomenon associated with cancer. Finally, we ask how differentiating cells regulate centriole maintenance/elimination in the context of the organism. We focused this study on natural examples where centrioles are either removed (e.g. oogenesis and skeletal muscle) or maintained (e.g. ciliated neurons). By studying centriole disappearance in the female germline and cultured cells we uncovered that centrioles are much more dynamic than previously thought and that this is critical for their maintenance. We showed that while similar components promote centriole and cilia stability in muscle and neurons, the regulation of those components shows tissue specificity. The tissue specificity observed is likely to underlie differences in the symptoms affecting diseases caused by deregulation of these structures (infertility, ciliopathies, cancer, amongst others). Future studies should aim at understanding how these different mechanisms are regulated and deregulated. This will provide novel insights to diagnostics and treatment of human diseases originated by centriole and cilia abnormalities. Besides scientific research, our mission has also been one of training scientists that have started their independent career, as well as communicating science to lay people.
In this project we have published important aspects of the mechanisms controlling centriole biogenesis and structure (Gouveia and Zitouni et al, 2019; Ito et al, 2019; Nabais et al, 2021; Gomes Pereira et al, 2021), as well as centrosome number control (Arbi et al, BioRxiv; Dias-Louro et al, 2021; Dias-Louro et al, BioRxiv) and maintenance of the centriole-cilium complex (Jana et al, 2018; Marques et al, BioRxiv; Werner et al, BioRxiv).
Our results highlight how the structure that surrounds the centrioles, the matrix, previously thought to only have a role in microtubule nucleation, also has a role in concentrating centriole components. This role is very important for centriole de novo formation and also for the maintenance of the centrosome-cilium complex.This is a major change in paradigm. Moreover, we have shown that PLK4, the major trigger of centriole biogenesis, forms condensates, which accumulate components essential for centriole biogenesis. These studies are a relevant contribution for the comprehension of cellular mechanisms controlling centriole number and a new step forward to identify and correct deregulated processes in human disease.
These studies were widely disseminated through original publications, as well as reviews and conference attendance, to the scientific community. Moreover these studies were also widely disseminated through our website, social media platforms, as well as traditional media. Finally, 5 PhD students were involved in the work reported here, three of which have already finished and have successfully progressed to the next step in their career.
Our results highlight how the structure that surrounds the centrioles, the matrix, previously thought to only have a role in microtubule nucleation, also has a role in concentrating centriole components. This role is very important for centriole de novo formation and also for the maintenance of the centrosome-cilium complex.This is a major change in paradigm. Moreover, we have shown that PLK4, the major trigger of centriole biogenesis, forms condensates, which accumulate components essential for centriole biogenesis. These studies are a relevant contribution for the comprehension of cellular mechanisms controlling centriole number and a new step forward to identify and correct deregulated processes in human disease.
These studies were widely disseminated through original publications, as well as reviews and conference attendance, to the scientific community. Moreover these studies were also widely disseminated through our website, social media platforms, as well as traditional media. Finally, 5 PhD students were involved in the work reported here, three of which have already finished and have successfully progressed to the next step in their career.
Our results elucidated different mechanisms regulating the birth of new centrioles, as well as centriole death; two aspects essential in centriole number control, a process deregulated in cancer.
We have introduced new concepts into the regulation of centriole biogenesis and stability:
-a new role for the matrix
-a new state for PLK4 (condensate)
-the use of evolution-related experiments to show diversity in centriole biogenesis mechanisms, as well as how centriole number is controlled.
We developed different experimental strategies which go well beyond the state of the art, such as the Drosophila extract, the use of mosses, and using experimental evolution to study centriole number control. Besides the conceptual data, the experimental tools are also important for the scientific community.
We have introduced new concepts into the regulation of centriole biogenesis and stability:
-a new role for the matrix
-a new state for PLK4 (condensate)
-the use of evolution-related experiments to show diversity in centriole biogenesis mechanisms, as well as how centriole number is controlled.
We developed different experimental strategies which go well beyond the state of the art, such as the Drosophila extract, the use of mosses, and using experimental evolution to study centriole number control. Besides the conceptual data, the experimental tools are also important for the scientific community.