• Acentrosomal asters are small populations of microtubules that are nucleated on or around the condensed chromosomes at the beginning of mitosis. (radikes.com)
  • Remarkably, despite the high turnover of microtubules throughout mitosis 2 , the spindle maintains its bipolar structure with the chromosomes at its center and two poles that are separated by the plane of cell division. (nature.com)
  • Moreover, the implication that the active form of Ran is concentrated in the vicinity of chromosomes suggests that these findings may resolve the long-standing question of how chromosomes can influence spindle assembly in the absence of microtubule-nucleating organelles (i.e., as in plant mitosis or mammalian meiosis). (silverchair.com)
  • In addition, these drugs are known to induce serious side effects due to inhibition of mitosis in other proliferating cells (mainly bone marrow and gut) as well as inhibition of other microtubules-dependent functions, such as neuronal processes [ 18 , 19 ]. (biomedcentral.com)
  • We classify them as kinetochore (KMTs), spindle (SMTs) or astral microtubules (AMTs) according to their positions, and quantify distinct properties of each class. (nature.com)
  • Instead, Ran and its associated proteins shift their focus from nuclear transport to the regulation of microtubule dynamics. (silverchair.com)
  • A family of microtubule-associated proteins (or 'MAPs' for short) bind to microtubules and assist in organising the filaments, but it is not clear how they work. (elifesciences.org)
  • The experiments also found that oMAP4 can create links between different microtubules and act as a brake to prevent the filaments being moved excessively by motor proteins. (elifesciences.org)
  • Formins are multidomain proteins defined by a conserved FH2 (formin homology 2) domain with actin nucleation activity preceded by a proline-rich FH1 (formin homology 1) domain. (biomedcentral.com)
  • In vitro, the FH2 domain competes with barbed-end capping proteins and is necessary and sufficient to nucleate actin polymerization, but the FH1 domain, which interacts with profilin-actin, funnels actin to the nucleation vicinity and confers full activity to the molecule [ 1 ]. (biomedcentral.com)
  • In the lab of Dr. Isabelle Vernos at the Center for Genomic Regulation in Barcelona, Spain I investigated microtubule dynamics during cell division. (radikes.com)
  • In addition to this cell work I learned how to harvest Xenopus laevis extracts, how to deplete key mitotic regulators from the extract and how to induce the formation of spindles in these extracts, in order to probe how key mitotic factors regulate microtubules dynamics and spindle formation. (radikes.com)
  • It is predicted that MCPH gene mutations may lead to the disease phenotype due to a disturbed mitotic spindle orientation, premature chromosomal condensation, signalling response as a result of damaged DNA, microtubule dynamics, transcriptional control or a few other hidden centrosomal mechanisms that can regulate the number of neurons produced by neuronal precursor cells. (biomedcentral.com)
  • In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. (biomedcentral.com)
  • Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. (hipi-lab-saint-louis.fr)
  • Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. (hipi-lab-saint-louis.fr)
  • Here, we report that AQP5 promotes microtubule assembly and helps maintain the assembled microtubule steady state levels with slower turnover dynamics in cells . (plos.org)
  • These findings indicate that AQP5-mediated regulation of microtubule dynamics modulates airway epithelial barrier properties and epithelial function. (plos.org)
  • Since the centrosome organizes the microtubules of a cell, it has to do with the formation of the mitotic spindle, polarity and, therefore, cell shape, as well as all other processes having to do with the mitotic spindle. (wikipedia.org)
  • FAM29A promotes microtubule amplification via recruitment of the NEDD1-gamma-tubulin complex to the mitotic spindle. (nih.gov)
  • The microtubule-associated protein EML3 regulates mitotic spindle assembly by recruiting the Augmin complex to spindle microtubules. (nih.gov)
  • The mitotic spindle is a dynamic microtubule-based apparatus that ensures the segregation of chromosomes during cell division. (nature.com)
  • Our analysis allows some preliminary insight into the functionality of Dictyostelium formins: all isoforms might display actin nucleation activity and, with the exception of ForI, might also be susceptible to autoinhibition and to regulation by Rho GTPases. (biomedcentral.com)
  • In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. (hipi-lab-saint-louis.fr)
  • Failure of centrosome regulation can cause mistakes in chromosome segregation and is associated with aneuploidy. (wikipedia.org)
  • Cell cycle regulation of centrosome duplication Centrosomes are only supposed to replicate once in each cell cycle and are therefore highly regulated. (wikipedia.org)
  • Indeed, by quantitatively analysing several models of microtubule growth, we conclude that minus-ends of KMTs have selectively detached and depolymerized from the centrosome. (nature.com)
  • They develop in a juxtanuclear position, adjacent to the centrosome, the microtubule organizing centre of the cell, and share some protein components. (biorxiv.org)
  • We investigated whether the formation of aggresomes affected key centrosome functions: its ability to organize the microtubule network and to promote cilia formation. (biorxiv.org)
  • The juxtanuclear location of the aggresome is shared by the centrosome, the microtubule organising centre of the cell. (biorxiv.org)
  • The augmin complex plays a role in microtubule attachment to the kinetochore and central spindle formation. (nih.gov)
  • Augmin accumulation on long-lived microtubules drives amplification and kinetochore-directed growth. (nih.gov)
  • I was interested in determining if the mitotic kinesins and dynein played a role in nucleation, stabilization and/or organization of the acentrosomal asters. (radikes.com)
  • Most notably, oMAP4 is required for paraxial microtubule organisation in muscle cells and prevents dynein- and kinesin-driven microtubule-microtubule sliding. (elifesciences.org)
  • We propose a model in which the cooperation of dynein-mediated microtubule transport and oMAP4-mediated zippering of microtubules drives formation of a paraxial microtubule array that provides critical support for the polarisation and elongation of myotubes. (elifesciences.org)
  • Dynein is the sole processive minus-end-directed microtubule motor found in animals. (biologists.com)
  • Together with dynactin, dynein regulates centrosomal orientation to establish and maintain cell polarity, controls focal adhesion turnover and anchors microtubules at the leading edge. (biologists.com)
  • Researchers at the Centre for Genomic Regulation in Barcelona find evidence that specialized secretory cells found in these unique and ancient creatures may have given rise to neurons in more complex animals. (sciforums.com)
  • Present address: Department of Cell and Developmental Biology, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain. (biologists.com)
  • I found motors that seemed to affect microtubule nucleation or stabilization, microtubule polymerization, and microtubule organization. (radikes.com)
  • The spindle microtubule (MT) exhibits highly regulated dynamic instability, with frequent polymerization and depolymerization occurring at both the plus and minus ends. (biomedcentral.com)
  • Centrosomes are the major microtubule organizing centers (MTOC) in mammalian cells. (wikipedia.org)
  • While our light microscopy and mutant studies show that microtubules are nucleated from the centrosomes, we find only a few KMTs directly connected to the centrosomes. (nature.com)
  • In this study, we identify a previously uncharacterised isoform of microtubule-associated protein MAP4, oMAP4, as a microtubule organising factor that is crucial for myogenesis. (elifesciences.org)
  • Although the positioning signal is likely to be transmitted via the anaphase microtubule array to the cell cortex, exactly how the microtubule array determines the site of contractile ring formation remains unresolved. (biologists.com)
  • These data support a model in which Tum/RacGAP, via its interaction with Pbl, provides a critical link between the anaphase microtubule spindle and cytokinetic furrow formation in Drosophila cells. (biologists.com)
  • This protein may have a role in efficient chromosome congression and segregation by promoting microtubule-dependent microtubule amplification. (nih.gov)
  • The microtubules in cells that make smaller amounts of this protein were more disorganised, and these cells were unable to fuse with each other to form muscle cells. (elifesciences.org)
  • In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos , mre1 , any1 , prc1-1 and rsw1 , and the Cellulose Synthase Interacting 1 protein ( csi1) mutant pom2-4 . (biomedcentral.com)
  • K can From a variety of extracellular Ren stimuli Ren Ren signals such as growth factors, ligands for G-protein-coupled receptors, cytokines, and vitamin D3, the p85 subunit of regulation at the plasma membrane, such as catalytic subunit recruit p110 PI P2 4 5 PI converts 3.4, 5 P3. (microrna1.com)
  • Depletion of PIP4KIIγ enhanced the spindle pole accumulation of mitotic centromere-associated kinesin (MCAK), a microtubule (MT)-depolymerizing kinesin, and resulted in a less stable spindle pole-associated MT. Depletion of MCAK can ameliorate PIP4KIIγ depletion-induced spindle abnormalities. (biomedcentral.com)
  • While regulation of local water flux could contribute to these processes, the specific mechanisms by which these processes are mediated are not defined. (plos.org)
  • It also undergoes specific processes in each step of cell division due to the heavy regulation, which is why the process is so efficient. (wikipedia.org)
  • Is consciousness to be found in quantum processes in microtubules? (sciforums.com)
  • Therefore, the next challenge is to understand how other processes-such as the selective stabilisation of some microtubules and the movement of cell materials along the microtubules-cooperate to control muscle fibre formation. (elifesciences.org)
  • Purified oMAP4 aligns dynamic microtubules into antiparallel bundles that withstand motor forces in vitro. (elifesciences.org)
  • The role of microtubule pivoting in formation of complex structures such as microtubule bundles and mitotic spindles. (irb.hr)
  • For example, the mother centriole can nucleate and organize microtubules, whereas the daughter centriole can only nucleate. (wikipedia.org)
  • Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. (biomedcentral.com)
  • Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. (biomedcentral.com)
  • Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. (biomedcentral.com)
  • The regulatory role of cortical microtubules on cellulose microfibrils was initially postulated, and remains widely accepted, by the "alignment hypothesis" [ 4 ]. (biomedcentral.com)
  • However, cortical microtubules reside just under the plasma membrane, while cellulose microfibrils are synthesized by transmembrane CSCs [ 6 ], consisting of CESA subunits. (biomedcentral.com)
  • Even though the "alignment hypothesis" has been proposed decades ago, a mechanism explaining how cortical microtubules, located inside of the plasma membrane, control the orientation of cellulose microfibrils, outside of the protoplast, remained ambiguous. (biomedcentral.com)
  • Apart from the role of cortical microtubules on cellulose microfibril orientation, several authors supported that CESA activity and cellulose synthesis also exert an effect on cortical microtubule orientation, suggesting thus that cortical microtubule-cellulose microfibril relationship is bi-directional. (biomedcentral.com)
  • While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. (biomedcentral.com)
  • According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. (biomedcentral.com)
  • Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules. (biomedcentral.com)
  • In contrast, overexpression of AQP5 increased assembly of microtubules, with evidence of increased MT stability, and promoted the formation of long straight microtubules in the apical domain of the epithelial cells. (plos.org)
  • The class II PI3K isoform PI3K-C2β was downregulated in prostate cancer PC3 cells and cervical cancer HeLa cells using selective siRNAs and the effect on cell growth was determined in the absence or presence of the microtubule-stabilizing agent/anti-cancer drug docetaxel. (biomedcentral.com)
  • These tools allow us to analyze and quantify actin and microtubule networks in cells of controled and regular shapes. (hipi-lab-saint-louis.fr)
  • We find that when aggresomes are present, neuronal cells are unable to organise their microtubule network. (biorxiv.org)
  • Using a microtubule regrowth assay, I observed the nucleation and formation of acentrosomal asters through immunofluorescence and confocal time-lapse imaging. (radikes.com)
  • used microscopy to observe the formation of the microtubule filaments in living myoblasts. (elifesciences.org)
  • The direct observation of CESA complexes sliding on the plasma membrane over the cortical microtubules [ 5 ] directly supported the model of Heath [ 16 ]. (biomedcentral.com)
  • Recent findings by several groups have shown that the GTP-bound form of Ran is necessary for the nucleation and organization of microtubule structures during M phase. (silverchair.com)
  • The GAP activity of Tum is required for cytokinesis: in its absence cytokinesis fails early even though Tum is present on microtubules at the cell equator where the furrow should form. (biologists.com)
  • New microtubules are not nucleated and extended, and the cells fail to respond to polarity cues. (biorxiv.org)
  • Actin filaments and microtubules form such complex intricate networks in cells that it is difficult to identify the principles of their self-organization. (hipi-lab-saint-louis.fr)
  • In airway epithelial cells, altered AQP5 abundance is associated with changes in actin organization and in desmoplakin localization, which could contribute to the changes in paracellular permeability. (plos.org)
  • PI3K class I, which is essential in the regulation of cell survival, metabolism, apoptosis and cell cycle of the heterodimeric class I molecules of a catalyst composition PI3Ks regulatory subunit and are classified in class IA or IB PI3K class. (microrna1.com)