Centrosome Loss in the Evolution of Planarians

Azimzadeh, Juliette; Wong, Mei Lie; Downhour, Diane Miller; Alvarado, Alejandro Sánchez; Marshall, Wallace F.

doi:10.1126/science.1214457

Cited by 159 publications

(196 citation statements)

References 23 publications

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“…Figure 3 and Table EV2 summarize the results for 73 core centrosomal proteins [including 58/61 proteins described in Azimzadeh et al (2012)]. The results obtained by iBAQ and SRM were generally in excellent agreement (Fig EV1E), confirming that label‐free quantification provides useful, albeit approximate, information about protein abundance (Ahrne et al , 2013).…”

Section: Resultssupporting

confidence: 57%

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

et al. 2016

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Centrioles are essential for the formation of centrosomes and cilia. While numerical and/or structural centrosomes aberrations are implicated in cancer, mutations in centriolar and centrosomal proteins are genetically linked to ciliopathies, microcephaly, and dwarfism. The evolutionarily conserved mechanisms underlying centrosome biogenesis are centered on a set of key proteins, including Plk4, Sas‐6, and STIL, whose exact levels are critical to ensure accurate reproduction of centrioles during cell cycle progression. However, neither the intracellular levels of centrosomal proteins nor their stoichiometry within centrosomes is presently known. Here, we have used two complementary approaches, targeted proteomics and EGFP‐tagging of centrosomal proteins at endogenous loci, to measure protein abundance in cultured human cells and purified centrosomes. Our results provide a first assessment of the absolute and relative amounts of major components of the human centrosome. Specifically, they predict that human centriolar cartwheels comprise up to 16 stacked hubs and 1 molecule of STIL for every dimer of Sas‐6. This type of quantitative information will help guide future studies of the molecular basis of centrosome assembly and function.

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Section: Resultssupporting

confidence: 57%

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

et al. 2016

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“…Inactivation of a majority of these conserved genes affects centriole assembly or the function of cilia in planarian ciliated cells, supporting that they are indeed centriolar components [103]. Only a handful of centrosome components are missing from the planarian genome, most notably homologues for SPD-2/Cep192 and centrosomin (CNN)/CDK5RAP2 (Drosophila/human proteins), which are both major components of the PCM.…”

Section: Is the Molecular Composition Of The Centrosome Conserved?mentioning

confidence: 99%

Exploring the evolutionary history of centrosomes

Azimzadeh

2014

Phil. Trans. R. Soc. B

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The centrosome is the main organizer of the microtubule cytoskeleton in animals, higher fungi and several other eukaryotic lineages. Centrosomes are usually located at the centre of cell in tight association with the nuclear envelope and duplicate at each cell cycle. Despite a great structural diversity between the different types of centrosomes, they are functionally equivalent and share at least some of their molecular components. In this paper, we explore the evolutionary origin of the different centrosomes, in an attempt to understand whether they are derived from an ancestral centrosome or evolved independently from the motile apparatus of distinct flagellated ancestors. We then discuss the evolution of centrosome structure and function within the animal lineage.

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“…Scale bar, 5 μm notion of the centrosomal anchor can be discarded as it is clear that closed-loop conditions cannot be satisfied if centrosomes are not themselves anchored. Despite their potential roles in spindle assembly, centrosomes should not be regarded as essential components of a minimal mechanical spindle, as underlined by the fact that many systems (e.g., land plants, vertebrate oocytes, and planarians) perform normal division in their absence (Zhang and Dawe 2011;Doubilet and McKim 2007;Azimzadeh et al 2012). …”

Section: Basic Physical Principles Behind Mitotic Spindle Mechanicsmentioning

confidence: 99%

Maturation of the kinetochore-microtubule interface and the meaning of metaphase

Pereira

Maiato

2012

Chromosome Res

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Chromosome positioning at the equator of the mitotic spindle emerges out of a relatively entropic background. At this moment, termed metaphase, all kinetochores have typically captured microtubules leading to satisfaction of the spindle-assembly checkpoint, but the cell does not enter anaphase immediately. The waiting time in metaphase is related to the kinetics of securin and cyclin B1 degradation, which trigger sisterchromatid separation and promote anaphase processivity, respectively. Yet, as judged by metaphase duration, such kinetics vary widely between cell types and organisms, with no evident correlation to ploidy or cell size. During metaphase, many animal and plant spindles are also characterized by a conspicuous "flux" activity characterized by continuous poleward translocation of spindle microtubules, which maintain steady-state length and position. Whether spindle microtubule flux plays a specific role during metaphase remains arguable. Based on known experimental parameters, we have performed a comparative analysis amongst different cell types from different organisms and show that spindle length, metaphase duration and flux velocity combine within each system to obey a quasi-universal rule. As so, knowledge of two of these parameters is enough to estimate the third. This trend indicates that metaphase duration is tuned to allow approximately one kinetochore-to-pole round of microtubule flux. We propose that the time cells spend in metaphase evolved as a quality enhancement step that allows for the uniform stabilization/correction of kinetochore-microtubule attachments, thereby promoting mitotic fidelity.

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Centrosome Loss in the Evolution of Planarians

Cited by 159 publications

References 23 publications

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

Exploring the evolutionary history of centrosomes

Maturation of the kinetochore-microtubule interface and the meaning of metaphase

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