• 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)
  • Centrosome maturation is defined as the increase or accumulation of γ-tubulin ring complexes and other PCM proteins at the centrosome. (wikipedia.org)
  • Based on our analysis of requirements for CLS-2, a member of the CLASP family of proteins that stabilize microtubules, we recently proposed that a balance of actomyosin-mediated tension and microtubule-mediated stiffness limits membrane ingression throughout the oocyte during meiosis I polar body extrusion. (bvsalud.org)
  • Instead, Ran and its associated proteins shift their focus from nuclear transport to the regulation of microtubule dynamics. (silverchair.com)
  • While plants employ some evolutionarily conserved proteins to regulate spindle morphogenesis and remodeling, many essential spindle assembly factors found in vertebrates are either missing or not required for producing the plant bipolar microtubule array. (nsf.gov)
  • It is intriguing what proteins are associated with plant‐specific MTOC s and how plant cells activate or inactivate MT nucleation activities in spatiotemporally regulated manners. (nsf.gov)
  • 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)
  • We investigate the role of proteins associated to cell adhesions and actin cables as well as the effect of actin cable's size, number and spatial organization in cells. (cerclefser.org)
  • The microtubules and actin filaments within the phragmoplast serve to guide vesicles with cell wall material to the growing cell plate. (sciforums.com)
  • In particular we investigate the production and balance of mechanical forces in the networks of actin filaments and microtubules. (hipi-lab-saint-louis.fr)
  • 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)
  • These tools allow us to analyze and quantify actin and microtubule networks in cells of controled and regular shapes. (hipi-lab-saint-louis.fr)
  • 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)
  • 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)
  • Similar to the formation of actin filaments from the self-assembly of actin monomers, tubulin forms asymmetric dimers that can self-assemble into microtubules. (cerclefser.org)
  • Compared with actin filaments, microtubules are much more rigid, and almost straight in the dimensions of a single cell. (cerclefser.org)
  • Microtubules can sustain much higher compression forces than actin filament but are not as numerous as actin filaments. (cerclefser.org)
  • A centrosome is composed of two orthogonal cylindrical protein assemblies, called centrioles, which are surrounded by a protein dense amorphous cloud of pericentriolar material (PCM). (wikipedia.org)
  • Each daughter cell inherits two centrioles (one centrosome) surrounded by pericentriolar material as a result of cell division. (wikipedia.org)
  • The centrosome consists of a pair of centrioles and a surrounding matrix of pericentriolar material that anchors microtubule nucleation sites and consequently determines the number and organization of microtubules in interphase and mitotic cells. (elsevierpure.com)
  • Recent studies utilizing a functional genomics approach in the nematode worm Caenorhabditis elegans and sophisticated light and electron microscopy techniques provide new insight into how centrioles act as centrosomal organizers and use a centriolar structural element to dictate centrosome size by defining their capacity to recruit pericentriolar material. (elsevierpure.com)
  • Within the cell, the arrangement of microtubules is controlled by a variety of discreet microtubule-organizing centers (MTOCs), but in most cells, the dominant MTOC is the centrosome, a bipartite structure consisting of a central pair of barrel-shaped centrioles and a surrounding matrix of pericentriolar material (PCM). (nih.gov)
  • In the past several years it has become apparent that defects in centrosomes and centrioles are linked to, and even causative of, a growing number of human diseases including cancer, microcephaly, and dwarfism. (nih.gov)
  • The centrioles contain nine microtubule triplets and mature into a centrosome that is referred to as a basal body in the context of ciliogenesis [ 22 , 23 ]. (biomedcentral.com)
  • Centrosomes are the major microtubule organizing centers (MTOC) in mammalian cells. (wikipedia.org)
  • In contrast to well-studied fungal and animal cells, plant cells assemble bipolar spindles that exhibit a great deal of plasticity in the absence of structurally defined microtubule-organizing centers like the centrosome. (nsf.gov)
  • Although many key factors contributing to MT nucleation and organization are well conserved in different kingdoms, the centrosome, representing the most prominent microtubule organizing centers ( MTOC s), disappeared during plant evolution as angiosperms lack the structure. (nsf.gov)
  • In the meiosis of many species, the process of chromosome segregation requires that bipolar spindles be formed without the aid of dedicated microtubule organizing centers, such as centrosomes. (nsf.gov)
  • Microtubule nucleation is mediated by γ-tubulin ring complexes (γ-TuRCs). (bvsalud.org)
  • In Drosophila, Spindle defective-2 (Spd-2) and Centrosomin (Cnn) redundantly recruit γ-tubulin complexes to mitotic centrosomes. (bvsalud.org)
  • FAM29A promotes microtubule amplification via recruitment of the NEDD1-gamma-tubulin complex to the mitotic spindle. (nih.gov)
  • MT ‐dependent MT nucleation is particularly noticeable in plant cells because it accounts for the primary source of MT generation for assembling spindle, phragmoplast, and cortical arrays when the γ‐tubulin ring complex is anchored and activated by the augmin complex. (nsf.gov)
  • The pivotal structure of the primary cilia is a microtubule that is generated via tubulin polymerization reaction that occurs in the basal body. (biomedcentral.com)
  • CP110 is an important centrosomal protein that is phosphorylated by both mitotic and interphase Cdk/cyclin complexes and is thought to influence centrosome duplication in the S phase. (wikipedia.org)
  • Salisbury, JL 2003, ' Centrosome size is controlled by centriolar SAS-4 ', Trends in Cell Biology , vol. 13, no. 7, pp. 340-343. (elsevierpure.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)
  • 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)
  • 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)
  • Considering that the complexity of the intra-cellular biochemical conditions may partially hinder the physical rules we want to investigate, we are also developing alternative methods to analyze cytoskeleton self-organization in controlled biochemical conditions in vitro by mixing, in defined proportions, the individual cytoskeleton components. (hipi-lab-saint-louis.fr)
  • To address such questions, my lab utilizes genetic and biochemical approaches to study centrosome biology in a simple model system, the small nematode worm, Caenorhabditis elegans . (nih.gov)
  • We discuss the possibility that this regulation of sub-cortical microtubule dynamics facilitates actomyosin contractile ring dynamics during C. elegans oocyte meiosis I cell division. (bvsalud.org)
  • The spatial organization of these filaments and their dynamics of assembly direct cell shape and cell motion. (cerclefser.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)
  • 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)
  • 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)
  • The spindle microtubule (MT) exhibits highly regulated dynamic instability, with frequent polymerization and depolymerization occurring at both the plus and minus ends. (biomedcentral.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)
  • In toto , our results show that the connection between centrosomes and chromosomes is mediated by an anchoring into the entire spindle network and that any direct connections through KMTs are few and likely very transient. (nature.com)
  • The mitotic spindle is a dynamic microtubule-based apparatus that ensures the segregation of chromosomes during cell division. (nature.com)
  • Of note, compared to fungal and animal systems, relatively little is known about how plant cells remodel the spindle microtubule array during anaphase. (nsf.gov)
  • The centriole is the inner core of the centrosome, and its conformation is typically somewhat like that of spokes on a wheel. (wikipedia.org)
  • This pair is precisely duplicated in S phase to yield two centriole pairs (and thus two centrosomes). (nih.gov)
  • As each pole of the spindle is organized by a centrosome, defects in centriole duplication can disrupt spindle bipolarity and chromosome segregation, leading to genome instability. (nih.gov)
  • The juxtanuclear location of the aggresome is shared by the centrosome, the microtubule organising centre of the cell. (biorxiv.org)
  • While our understanding of centrosome biogenesis and function has advanced significantly in recent years, much still needs to be learned about how the number, size and activity of centrosomes are determined. (nih.gov)
  • Plant spindle assembly initiates with microtubule nucleation on the nuclear envelope followed by bipolarization into the prophase spindle. (nsf.gov)
  • The implications of those findings have influenced almost all further research of intracellular processes, including RAS signaling, immune synapses, DNA repair, transcriptional activation, and the functions of nuclear pores, the nucleolus and centrosomes. (hymanlab.org)
  • Augmin accumulation on long-lived microtubules drives amplification and kinetochore-directed growth. (nih.gov)
  • 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)
  • Here we combine the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with live-cell imaging to reconstruct all microtubules in 3D and identify their plus- and minus-ends. (nature.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 reproducible shape and spatial organization of organs imply the existence of physical rules directing the assembly of complex biological structures. (cerclefser.org)
  • The formation of controlled and reproducible geometrical structures relies on the self-organization properties of these networks. (cerclefser.org)
  • Cytoskeletal microtubules ( MT s) have a multitude of functions including intracellular distribution of molecules and organelles, cell morphogenesis, as well as segregation of the genetic material and separation of the cytoplasm during cell division among eukaryotic organisms. (nsf.gov)
  • This philosophy from early in my scientific career stuck with me, and I believe was instrumental in my lab's contribution to the discovery of multivalency-driven liquid-liquid phase separation as a general principle in cell organization. (hymanlab.org)
  • The purified recombinant Dam1 complex containing either Dad2ΔDSS or Dad2R126A failed to bind microtubules (MTs) or form any visible rings like the WT complex. (bvsalud.org)
  • This protein may have a role in efficient chromosome congression and segregation by promoting microtubule-dependent microtubule amplification. (nih.gov)
  • The augmin complex plays a role in microtubule attachment to the kinetochore and central spindle formation. (nih.gov)
  • The microtubule-associated protein EML3 regulates mitotic spindle assembly by recruiting the Augmin complex to spindle microtubules. (nih.gov)
  • Electron tomography and 3D modeling identifies augmin-dependent connections between the wall of one microtubule and the minus end of a neighboring one in the spindle. (silverchair.com)
  • It is one aim of our study to identify the nature of the KMT-centrosome connection in C. elegans , which is so far unknown. (nature.com)
  • We further show that KNL-1 and BUB-1, like CLS-2, promote the proper organization of sub-cortical microtubules and also limit membrane ingression throughout the oocyte. (bvsalud.org)
  • We propose that linear elements influence the organization of sub-cortical microtubules to generate a stiffness that limits cortical actomyosin-driven membrane ingression throughout the oocyte during meiosis I polar body extrusion. (bvsalud.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)
  • 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)
  • The centrosome cycle is important to ensure that daughter cells receive a centrosome after cell division. (wikipedia.org)
  • The centrosome cycle consists of four phases that are synchronized to the cell cycle. (wikipedia.org)
  • Centrosome duplication is heavily regulated by cell cycle controls. (wikipedia.org)
  • This link between the cell cycle and the centrosome cycle is mediated by cyclin-dependent kinase 2 (Cdk2). (wikipedia.org)
  • They develop in a juxtanuclear position, adjacent to the centrosome, the microtubule organizing centre of the cell, and share some protein components. (biorxiv.org)
  • Despite the long-standing observation that aggresomes/Lewy bodies and the centrosome sit side-by-side in the cell, no studies have been done to see whether these protein accumulations impede the organelle function. (biorxiv.org)
  • Since dopaminergic neurons are polarised, ensuring correct localisation of organelles and the effective intracellular transport of neurotransmitter vesicles, loss of centrosome activity could contribute to loss of dopaminergic function and neuronal cell death in Parkinson's disease. (biorxiv.org)
  • Cell growth, division, and motility are highly dependent upon an organized and dynamic microtubule cytoskeleton. (nih.gov)
  • The ultimate goal of my lab is to understand the molecular mechanisms that are used to control the number and size of centrosomes. (nih.gov)
  • We find that when aggresomes are present, neuronal cells are unable to organise their microtubule network. (biorxiv.org)
  • New microtubules are not nucleated and extended, and the cells fail to respond to polarity cues. (biorxiv.org)
  • 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 most animal cells, the MT network forms as an aster in which microtubules radiate from the centrosome, the main microtubule organizing center. (cerclefser.org)
  • There has been ample evidence that Cdk2 is necessary for both DNA replication and centrosome duplication, which are both key events in S phase. (wikipedia.org)
  • It has also been shown that Cdk2 complexes with both cyclin A and cyclin E and this complex is critical for centrosome duplication. (wikipedia.org)