Control of Centriole Structure And Number

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Organizational Unit

Publications

Publication . Bettencourt-Dias, Mónica

The centrosome has several functions. The central one is as the major microtubule organizing center (MTOC) in proliferating animal cells: thus, it helps to organize the microtubules that form the mitotic spindle in dividing cells, and orchestrate a wide variety of cellular processes, including cell motility, signaling, adhesion, coordination of protein trafficking by the microtubule cytoskeleton and the acquisition of polarity. The centrosome has crucial links to the nucleus, the Golgi, cell to cell junctions and acto-myosin cytoskeleton that are very important in positioning it and thus shaping the microtubule cytoskeleton in relation to the cell and the organism (reviewed in [1]). The role of the centrosome in organizing cellular microtubules can differ from cell to cell and be regulated differently in different phases of the life of a cell.

2013-04-11Journal article

Open access

PLK4 trans-Autoactivation Controls Centriole Biogenesis in Space

Publication . Lopes, Carla A.M.; Jana, Swadhin Chandra; Cunha-Ferreira, Inês; Zitouni, Sihem; Bento, Inês; Duarte, Paulo; Gilberto, Samuel; Freixo, Francisco; Guerrero, Adán; Francia, Maria; Lince-Faria, Mariana; Carneiro, Jorge; Bettencourt-Dias, Mónica

Centrioles are essential for cilia and centrosome assembly. In centriole-containing cells, centrioles always form juxtaposed to pre-existing ones, motivating a century-old debate on centriole biogenesis control. Here, we show that trans-autoactivation of Polo-like kinase 4 (PLK4), the trigger of centriole biogenesis, is a critical event in the spatial control of that process. We demonstrate that centrioles promote PLK4 activation through its recruitment and local accumulation. Though centriole removal reduces the proportion of active PLK4, this is rescued by concentrating PLK4 to the peroxisome lumen. Moreover, while mild overexpression of PLK4 only triggers centriole amplification at the existing centriole, higher PLK4 levels trigger both centriolar and cytoplasmatic (de novo) biogenesis. Hence, centrioles promote their assembly locally and disfavor de novo synthesis. Similar mechanisms enforcing the local concentration and/or activity of other centriole components are likely to contribute to the spatial control of centriole biogenesis under physiological conditions.

2015-10-26Journal article

Open access

CDK1 Prevents Unscheduled PLK4-STIL Complex Assembly in Centriole Biogenesis

Publication . Zitouni, Sihem; Francia, Maria E.; Leal, Filipe; Montenegro Gouveia, Susana; Nabais, Catarina; Duarte, Paulo; Gilberto, Samuel; Brito, Daniela; Moyer, Tyler; Kandels-Lewis, Steffi; Ohta, Midori; Kitagawa, Daiju; Holland, Andrew J.; Karsenti, Eric; Lorca, Thierry; Lince-Faria, Mariana; Bettencourt-Dias, Mónica

Centrioles are essential for the assembly of both centrosomes and cilia. Centriole biogenesis occurs once and only once per cell cycle and is temporally coordinated with cell-cycle progression, ensuring the formation of the right number of centrioles at the right time. The formation of new daughter centrioles is guided by a pre-existing, mother centriole. The proximity between mother and daughter centrioles was proposed to restrict new centriole formation until they separate beyond a critical distance. Paradoxically, mother and daughter centrioles overcome this distance in early mitosis, at a time when triggers for centriole biogenesis Polo-like kinase 4 (PLK4) and its substrate STIL are abundant. Here we show that in mitosis, the mitotic kinase CDK1-CyclinB binds STIL and prevents formation of the PLK4-STIL complex and STIL phosphorylation by PLK4, thus inhibiting untimely onset of centriole biogenesis. After CDK1-CyclinB inactivation upon mitotic exit, PLK4 can bind and phosphorylate STIL in G1, allowing pro-centriole assembly in the subsequent S phase. Our work shows that complementary mechanisms, such as mother-daughter centriole proximity and CDK1-CyclinB interaction with centriolar components, ensure that centriole biogenesis occurs once and only once per cell cycle, raising parallels to the cell-cycle regulation of DNA replication and centromere formation.

2016-05-09Journal article

Open access

Regulation of Autophosphorylation Controls PLK4 Self-Destruction and Centriole Number

Publication . Cunha-Ferreira, Inês; Bento, Inês; Pimenta-Marques, Ana; Jana, Swadhin Chandra; Lince-Faria, Mariana; Duarte, Paulo; Borrego-Pinto, Joana; Gilberto, Samuel; Amado, Tiago; Brito, Daniela; Rodrigues-Martins, Ana; Debski, Janusz; Dzhindzhev, Nikola; Bettencourt-Dias, Mónica

Polo-like kinase 4 (PLK4) is a major player in centriole biogenesis: in its absence centrioles fail to form, while in excess leads to centriole amplification. The SCF-Slimb/βTrCP-E3 ubiquitin ligase controls PLK4 levels through recognition of a conserved phosphodegron. SCF-Slimb/βTrCP substrate binding and targeting for degradation is normally regulated by phosphorylation cascades, controlling complex processes, such as circadian clocks and morphogenesis. Here, we show that PLK4 is a suicide kinase, autophosphorylating in residues that are critical for SCF-Slimb/βTrCP binding. We demonstrate a multisite trans-autophosphorylation mechanism, likely to ensure that both a threshold of PLK4 concentration is attained and a sequence of events is observed before PLK4 can autodestruct. First, we show that PLK4 trans-autophosphorylates other PLK4 molecules on both Ser293 and Thr297 within the degron and that these residues contribute differently for PLK4 degradation, the first being critical and the second maximizing auto-destruction. Second, PLK4 trans-autophosphorylates a phospho-cluster outside the degron, which regulates Thr297 phosphorylation, PLK4 degradation, and centriole number. Finally, we show the importance of PLK4-Slimb/βTrCP regulation as it operates in both soma and germline. As βTrCP, PLK4, and centriole number are deregulated in several cancers, our work provides novel links between centriole number control and tumorigenesis.

2013-11-18Journal article

Open access

A structural road map to unveil basal body composition and assembly

Publication . Jana, Swadhin C; Machado, Pedro; Bettencourt-Dias, Mónica

The Basal Body (BB) acts as the template for the axoneme, the microtubule‐basedstructure of cilia and flagella. Although several proteins were recently implicatedin both centriole and BB assembly and function, their molecular mechanisms are stillpoorly characterized. In this issue of The EMBO journal, Li and coworkersdescribe for the first time the near‐native structure of the BB at 33 Åresolution obtained by Cryo‐Electron Microscopy analysis of wild‐type (WT) isolatedChlamydomonas BBs. They identified several uncharacterized non‐tubulinstructures and variations along the length of the BB, which likely reflect thebinding and function of numerous macromolecular complexes. These complexes areexpected to define BB intrinsic properties, such as its characteristic structure andstability. Similarly to the high‐resolution structures of ribosome and nuclear porecomplexes, this study will undoubtedly contribute towards the future analysis ofcentriole and BB biogenesis, maintenance and function.

2012-02-01Journal article

Open access