scholarly journals Centrobin–tubulin interaction is required for centriole elongation and stability

2011 ◽  
Vol 193 (4) ◽  
pp. 711-725 ◽  
Author(s):  
Radhika Gudi ◽  
Chaozhong Zou ◽  
Jun Li ◽  
Qingshen Gao
Keyword(s):  
Molecular Mechanism ◽  
Early Stage ◽  
Centrosome Duplication ◽  
Centriole Duplication ◽  
The Stability ◽  
Daughter Centriole

Centrobin is a daughter centriole protein that is essential for centrosome duplication. However, the molecular mechanism by which centrobin functions during centriole duplication remains undefined. In this study, we show that centrobin interacts with tubulin directly, and centrobin–tubulin interaction is pivotal for the function of centrobin during centriole duplication. We found that centrobin is recruited to the centriole biogenesis site via its interaction with tubulins during the early stage of centriole biogenesis, and its recruitment is dependent on hSAS-6 but not centrosomal P4.1–associated protein (CPAP) and CP110. The function of centrobin is also required for the elongation of centrioles, which is likely mediated by its interaction with tubulin. Furthermore, disruption of centrobin–tubulin interaction led to destabilization of existing centrioles and the preformed procentriole-like structures induced by CPAP expression, indicating that centrobin–tubulin interaction is critical for the stability of centrioles. Together, our study demonstrates that centrobin facilitates the elongation and stability of centrioles via its interaction with tubulins.

scholarly journals Autophosphorylation of Polo-like Kinase 4 and Its Role in Centriole Duplication

2010 ◽  
Vol 21 (4) ◽  
pp. 547-561 ◽  
Author(s):  
James E. Sillibourne ◽  
Frederik Tack ◽  
Nele Vloemans ◽  
An Boeckx ◽  
Sathiesan Thambirajah ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Proteasome Inhibition ◽  
Centrosome Duplication ◽  
Active Fraction ◽  
Kinase Activation ◽  
Centriole Duplication ◽  
M Phase ◽  
Mother Centriole ◽  
Daughter Centriole

Centrosome duplication occurs once every cell cycle in a strictly controlled manner. Polo-like kinase 4 (PLK4) is a key regulator of this process whose kinase activity is essential for centriole duplication. Here, we show that PLK4 autophosphorylation of serine S305 is a consequence of kinase activation and enables the active fraction to be identified in the cell. Active PLK4 is detectable on the replicating mother centriole in G1/S, with the proportion of active kinase increasing through interphase to reach a maximum in mitosis. Activation of PLK4 at the replicating daughter centriole is delayed until G2, but a level equivalent to the replicating mother centriole is achieved in M phase. Active PLK4 is regulated by the proteasome, because either proteasome inhibition or mutation of the degron motif of PLK4 results in the accumulation of S305-phosphorylated PLK4. Autophosphorylation probably plays a role in the process of centriole duplication, because mimicking S305 phosphorylation enhances the ability of overexpressed PLK4 to induce centriole amplification. Importantly, we show that S305-phosphorylated PLK4 is specifically sequestered at the centrosome contrary to the nonphosphorylated form. These data suggest that PLK4 activity is restricted to the centrosome to prevent aberrant centriole assembly and sustained kinase activity is required for centriole duplication.

scholarly journals A molecular mechanism for the procentriole recruitment of Ana2

2019 ◽  
Vol 219 (2) ◽  
Author(s):  
Tiffany A. McLamarrah ◽  
Sarah K. Speed ◽  
John M. Ryniawec ◽  
Daniel W. Buster ◽  
Carey J. Fagerstrom ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Kinase Activity ◽  
Outer Wall ◽  
Single Site ◽  
Structural Motif ◽  
Centriole Duplication ◽  
Short Region ◽  
N Terminus ◽  
Mother Centriole ◽  
Daughter Centriole

During centriole duplication, a preprocentriole forms at a single site on the mother centriole through a process that includes the hierarchical recruitment of a conserved set of proteins, including the Polo-like kinase 4 (Plk4), Ana2/STIL, and the cartwheel protein Sas6. Ana2/STIL is critical for procentriole assembly, and its recruitment is controlled by the kinase activity of Plk4, but how this works remains poorly understood. A structural motif called the G-box in the centriole outer wall protein Sas4 interacts with a short region in the N terminus of Ana2/STIL. Here, we show that binding of Ana2 to the Sas4 G-box enables hyperphosphorylation of the Ana2 N terminus by Plk4. Hyperphosphorylation increases the affinity of the Ana2–G-box interaction, and, consequently, promotes the accumulation of Ana2 at the procentriole to induce daughter centriole formation.

scholarly journals A molecular mechanism for the procentriole recruitment of Ana2

2019 ◽  
Author(s):  
Tiffany A. McLamarrah ◽  
Sarah K. Speed ◽  
Daniel W. Buster ◽  
Carey J. Fagerstrom ◽  
Brian J. Galletta ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Kinase Activity ◽  
Surface Protein ◽  
Single Site ◽  
Centriole Duplication ◽  
C Terminus ◽  
N Terminus ◽  
Mother Centriole ◽  
Centriole Assembly ◽  
Daughter Centriole

AbstractCentriole duplication begins with the assembly of a pre-procentriole at a single site on a mother centriole and proceeds with the hierarchical recruitment of a conserved set of proteins, including Polo-like kinase 4 (Plk4)/ZYG-1, Ana2/SAS-5/STIL, and the cartwheel protein Sas6. During assembly, Ana2/STIL stimulates Plk4 kinase activity, and in turn, Ana2/STIL’s C-terminus is phosphorylated, allowing it to bind and recruit Sas6. The assembly steps immediately preceding Sas6-loading appear clear, but the mechanism underlying the upstream pre-procentriole recruitment of Ana2/STIL is not. In contrast to proposed models of Ana2/STIL recruitment, we recently showed that Drosophila Ana2 targets procentrioles independent of Plk4-binding. Instead, Ana2 recruitment requires Plk4 phosphorylation of Ana2’s N-terminus, but the mechanism explaining this process is unknown. Here, we show that the amyloid-like domain of Sas4, a centriole surface protein, binds Plk4 and Ana2, and facilitates phosphorylation of Ana2’s N-terminus which increases Ana2’s affinity for Sas4. Consequently, Ana2 accumulates at the procentriole to induce daughter centriole assembly.

PERFORMANCE OF THE ANALYTICAL PLOTTER

1963 ◽  
Vol 17 (2) ◽  
pp. 205-211
Author(s):  
T. J. Blachut
Keyword(s):  
Early Stage ◽  
Statistical Treatment ◽  
Measuring System ◽  
Stage Of Development ◽  
Pointing Accuracy ◽  
Analytical Accuracy ◽  
The Stability ◽  
Extensive Experimental Data ◽  
Mean Square Errors ◽  
Very High

In spite of the lack of extensive experimental data at this, in a sense, early stage of development, some very interesting indications of the eventual performance of the Analytical Plotter can be seen. The accuracy of the measuring system is very high; monocular grid measurements gave mean square errors of 2.5 - 3.5 μ. The stability is even better, repetition of readings being constant within 2 to 3 μ, that is, within the pointing accuracy. The accuracy of the complete system may be improved by using experimental corrections and proper statistical treatment of redundant observations. Complete relative and absolute orientations can be carried out in 10 to 15 minutes or less with analytical accuracy. Further economical advantages result from the use of the inherent computer capabilities to solve auxiliary problems and to carry out pertinent “real time” operations, such as automatic control of the plotting table.

Radiometric Dating of Ochoan (Permian) Evaporites, Wipp Site, Delaware Basin, New Mexico, Usa

1986 ◽  
Vol 84 ◽  
Author(s):  
Douglas G. Brookins ◽  
Steven J. Lambert
Keyword(s):  
New Mexico ◽  
Clay Minerals ◽  
Early Stage ◽  
Local Area ◽  
Radiometric Dating ◽  
Delaware Basin ◽  
Geochemical Study ◽  
Sulfate Salts ◽  
The Stability ◽  
Evaporite Minerals

AbstractWe have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant--a US DOE facility) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization, (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data, and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 ± 10 Ma, even when some sylvites yield lower K-Ar dates due to l1s of 40Ar*. K-Ar dates on leonites and kieserites are also low due to 40Ar* loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 ± 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 ± 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.

scholarly journals Characterization of a nucleopolyhedrovirus with a deletion of the baculovirus core gene Bm67

2008 ◽  
Vol 89 (3) ◽  
pp. 766-774 ◽  
Author(s):  
Jun-Qing Ge ◽  
Zhang-Nv Yang ◽  
Xu-Dong Tang ◽  
Hai-Jun Xu ◽  
Jian Hong ◽  
...  
Keyword(s):  
Early Stage ◽  
Microscopic Analysis ◽  
Core Gene ◽  
Pcr Analysis ◽  
Electron Microscopic ◽  
Reading Frame ◽  
Native Promoter ◽  
Budded Virus ◽  
The Stability ◽  
Conserved Gene

Open reading frame (ORF) 67 (Bm67) of the Bombyx mori nucleopolyhedrovirus (BmNPV) is a highly conserved gene that is found in all completely sequenced baculoviruses; its function is unknown. In the present study, a Bm67-knockout virus was generated for studying the role of Bm67 in the BmNPV infection cycle. Furthermore, a Bm67-repair bacmid was constructed by transposing the Bm67 native promoter-promoted Bm67 ORF into the polyhedrin locus of the Bm67-knockout bacmid. After these recombinant bacmids were transfected into BmN cells, the Bm67-knockout bacmid caused defects in the production of infectious budded viruses. However, the Bm67-repair bacmid could rescue the defect, and budded virus titres reached wild-type levels. Quantitative real-time PCR analysis indicated that Bm67 is required for normal levels of DNA synthesis or for the stability of nascent viral DNA at the early stage. Electron microscopic analysis revealed that the formation of normal-appearing nucleocapsids is reduced in Bm67-knockout bacmid-transfected cells, and nucleocapsids are rarely found in the cytoplasm. The presence of ‘enveloped’ nucleocapsids at the nucleoplasm bilayer indicated that they are enveloped abnormally. These results indicated that Bm67 is required for the production of infectious budded viruses and for assembly of envelope and nucleocapsids.

A lacustrine record of the early stage of the Miocene Climatic Optimum in Central Europe from the Most Basin, Ohře (Eger) Graben, Czech Republic

2014 ◽  
Vol 151 (6) ◽  
pp. 1013-1033 ◽  
Author(s):  
TOMÁŠ MATYS GRYGAR ◽  
KAREL MACH ◽  
PETR SCHNABL ◽  
PETR PRUNER ◽  
JIŘÍ LAURIN ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Early Stage ◽  
Sedimentary Environment ◽  
Magnetic Polarity ◽  
Early Miocene ◽  
Rift System ◽  
Age Model ◽  
Climatic Optimum ◽  
The Stability ◽  
Lake Deposits

AbstractThis study reports on a ~ 150 m thick macrofossil-barren sequence of siliciclastic sediments from a Burdigalian age (Early Miocene) freshwater lake. The lake was located within an incipient rift system of the Most Basin in the Ohře (Eger) Graben, which was part of the European Cenozoic Rift System, and had an original area of ≈ 1000 km2. Sediments from the HK591 core that cover the entire thickness of the lake deposits and some of the adjacent stratigraphic units were analysed by X-ray fluorescence spectroscopy (a proxy for element composition) and magnetic polarity measurement. The element proxies were subjected to frequency analysis, which provided estimated sedimentation rates, and allowed for sediment dating by magnetostratigraphy and orbital tuning of the age model. Based on the resulting age model and the known biostratigraphy, the lake was present between 17.4 and 16.6 Ma, which includes the onset of the Miocene Climatic Optimum in the latest Early Miocene. The identification of orbital forcing (precession, obliquity and short eccentricity cycles) confirms the stability of the sedimentary environment of the perennial lake in an underfilled basin. The dating allowed the sediment record to be interpreted in the context of the current knowledge of the European climate during that period. The stability of the sedimentary environment confirms that precipitation was relatively stable over the period recorded by the sediments.

scholarly journals Discovery of Alstrom syndrome gene as a regulator of centrosome duplication in asymmetrically dividing stem cells in Drosophila.: Supplementary table-mass spectrometry

2018 ◽  
Author(s):  
Cuie Chen ◽  
Yukiko Yamashita
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Germline Stem Cells ◽  
Causative Gene ◽  
Centriole Duplication ◽  
Alström Syndrome ◽  
Mother And Daughter ◽  
Dividing Cells ◽  
Alstrom Syndrome ◽  
Daughter Centriole

Stereotypical inheritance of the mother vs. daughter centrosomes has been reported in several stem cells that divide asymmetrically. We report the identification of a protein that exhibits asymmetric localization between mother and daughter centrosomes in asymmetrically dividing Drosophila male germline stem cells (GSCs). We show that Alms1a, a Drosophila homolog of the causative gene for the human ciliopathy Alstrom Syndrome, is a ubiquitous mother centriole protein with a unique additional localization to the daughter centriole only in the mother centrosome of GSCs. Depletion of alms1a results in rapid loss of centrosomes due to failure in daughter centriole duplication. We reveal that alms1a is specifically required for centriole duplication in asymmetrically dividing cells but not in symmetrically dividing differentiating cells in multiple stem cell lineages. The unique requirement of alms1a in asymmetric dividing cells may shed light onto the molecular mechanisms of Alstrom syndrome pathogenesis.

scholarly journals Protein phosphatase 1 down regulates ZYG-1 levels to limit centriole duplication

2016 ◽  
Author(s):  
Nina Peel ◽  
Jyoti Iyer ◽  
Anar Naik ◽  
Michael P Dougherty ◽  
Markus Decker ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Genome Stability ◽  
Protein Phosphatase 1 ◽  
Centrosome Duplication ◽  
C Elegans ◽  
Protein Levels ◽  
Hypomorphic Allele ◽  
Centriole Duplication ◽  
Daughter Cells ◽  
A Cell

AbstractIn humans perturbations of centriole number are associated with tumorigenesis and microcephaly, therefore appropriate regulation of centriole duplication is critical. The C. elegans homolog of Plk4, ZYG-1, is required for centriole duplication, but our understanding of how ZYG-1 levels are regulated remains incomplete. We have identified the two PP1 orthologs, GSP-1 and GSP-2, and their regulators I-2szy-2 and SDS-22 as key regulators of ZYG-1 protein levels. We find that down-regulation of PP1 activity either directly, or by mutation of szy-2 or sds-22 can rescue the loss of centriole duplication associated with a zyg-1 hypomorphic allele. Suppression is achieved through an increase in ZYG-1 levels, and our data indicate that PP1 normally regulates ZYG-1 through a post-translational mechanism. While moderate inhibition of PP1 activity can restore centriole duplication to a zyg-1 mutant, strong inhibition of PP1 in a wild-type background leads to centriole amplification via the production of more than one daughter centriole. Our results thus define a new pathway that limits the number of daughter centrioles produced each cycle.Author SummaryThe centrosomes are responsible for organizing the mitotic spindle a microtubule-based structure that centers, then segregates, the chromosomes during cell division. When a cell divides it normally possesses two centrosomes, allowing it to build a bipolar spindle and accurately segregate the chromosomes to two daughter cells. Appropriate control of centrosome number is therefore crucial to maintaining genome stability. Centrosome number is largely controlled by their regulated duplication. In particular, the protein Plk4, which is essential for duplication, must be strictly limited as an overabundance leads to excess centrosome duplication. We have identified protein phosphatase 1 as a critical regulator of the C. elegans Plk4 homolog (known as ZYG-1). When protein phosphatase 1 is down-regulated, ZYG-1 levels increase leading to centrosome amplification. Thus our work identifies a novel mechanism that limits centrosome duplication.

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