Browsing by Author "Machado, Pedro"
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- BLD10/CEP135 Is a Microtubule-Associated Protein that Controls the Formation of the Flagellum Central Microtubule PairPublication . Carvalho-Santos, Zita; Machado, Pedro; Alvarez-Martins, Inês; Gouveia, Susana M.; Jana, Swadhin C.; Duarte, Paulo; Amado, Tiago; Branco, Pedro; Freitas, Micael C.; Silva, Sara T.N.; Antony, Claude; Bandeiras, Tiago M.; Bettencourt-Dias, MónicaCilia and flagella are involved in a variety of processes and human diseases, including ciliopathies and sterility. Their motility is often controlled by a central microtubule (MT) pair localized within the ciliary MT-based skeleton, the axoneme. We characterized the formation of the motility apparatus in detail in Drosophila spermatogenesis. We show that assembly of the central MT pair starts prior to the meiotic divisions, with nucleation of a singlet MT within the basal body of a small cilium, and that the second MT of the pair only assembles much later, upon flagella formation. BLD10/CEP135, a conserved player in centriole and flagella biogenesis, can bind and stabilize MTs and is required for the early steps of central MT pair formation. This work describes a genetically tractable system to study motile cilia formation and provides an explanation for BLD10/CEP135's role in assembling highly stable MT-based structures, such as motile axonemes and centrioles.
- Differential regulation of transition zone and centriole proteins contributes to ciliary base diversityPublication . Jana, Swadhin Chandra; Mendonça, Susana; Machado, Pedro; Werner, Sascha; Rocha, Jaqueline; Pereira, António; Maiato, Helder; Bettencourt-Dias, MónicaCilia are evolutionarily conserved structures with many sensory and motility-related functions. The ciliary base, composed of the basal body and the transition zone, is critical for cilia assembly and function, but its contribution to cilia diversity remains unknown. Hence, we generated a high-resolution structural and biochemical atlas of the ciliary base of four functionally distinct neuronal and sperm cilia types within an organism, Drosophila melanogaster. We uncovered a common scaffold and diverse structures associated with different localization of 15 evolutionarily conserved components. Furthermore, CEP290 (also known as NPHP6) is involved in the formation of highly diverse transition zone links. In addition, the cartwheel components SAS6 and ANA2 (also known as STIL) have an underappreciated role in basal body elongation, which depends on BLD10 (also known as CEP135). The differential expression of these cartwheel components contributes to diversity in basal body length. Our results offer a plausible explanation to how mutations in conserved ciliary base components lead to tissue-specific diseases.
- Over-elongation of centrioles in cancer promotes centriole amplification and chromosome missegregationPublication . Marteil, Gaëlle; Guerrero, Adan; Vieira, André F; de Almeida, Bernardo P; Machado, Pedro; Mendonça, Susana; Mesquita, Marta; Villarreal, Beth; Fonseca, Irina; Francia, Maria E; Dores, Katharina; Martins, Nuno P; Jana, Swadhin C; Tranfield, Erin M; Barbosa-Morais, Nuno L; Paredes, Joana; Pellman, David; Godinho, Susana A; Bettencourt-Dias, MónicaCentrosomes are the major microtubule organising centres of animal cells. Deregulation in their number occurs in cancer and was shown to trigger tumorigenesis in mice. However, the incidence, consequence and origins of this abnormality are poorly understood. Here, we screened the NCI-60 panel of human cancer cell lines to systematically analyse centriole number and structure. Our screen shows that centriole amplification is widespread in cancer cell lines and highly prevalent in aggressive breast carcinomas. Moreover, we identify another recurrent feature of cancer cells: centriole size deregulation. Further experiments demonstrate that severe centriole over-elongation can promote amplification through both centriole fragmentation and ectopic procentriole formation. Furthermore, we show that overly long centrioles form over-active centrosomes that nucleate more microtubules, a known cause of invasiveness, and perturb chromosome segregation. Our screen establishes centriole amplification and size deregulation as recurrent features of cancer cells and identifies novel causes and consequences of those abnormalities.
- A structural road map to unveil basal body composition and assemblyPublication . Jana, Swadhin C; Machado, Pedro; Bettencourt-Dias, MónicaThe 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.