microtubule


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Related to microtubule: Intermediate filaments

microtubule

 [mi″kro-tu´būl]
any of the slender, tubular structures, composed chiefly of tubulin, found in the cytoplasmic ground substance of nearly all cells; they are involved in maintenance of cell shape and in the movements of organelles and inclusions, and form the spindle fibers of mitosis.

mi·cro·tu·bule

(mī'krō-tū'byūl),
A hollow, cylindric cytoplasmic element, 25 nm in diameter and of variable length, that occurs widely in the cytoskeleton, cilia, and flagella of cells; microtubules play a role in the maintenance of cell shape and increase in number during mitosis and meiosis, in which they are related to movement of the chromosomes by the nuclear spindle.

microtubule

/mi·cro·tu·bule/ (mi″kro-too´būl) any of the slender, tubular structures composed chiefly of tubulin, found in the cytoplasmic ground substance of nearly all cells; they are involved in maintenance of cell shape and in the movements of organelles and inclusions, and form the spindle fibers of mitosis.
Enlarge picture
Microtubules in a 9 + 2 array in a cross-section of the axoneme of a cilium.

microtubule

(mī′krō-to͞o′byo͞ol, -tyo͞o-)
n.
Any of the cylindrical hollow tubulin-containing structures that are found in the cytoplasm, cilia, and flagella of eukaryotic cells and are involved in determining cell shape and structure and directing the movement of organelles and chromosomes. Microtubules, along with microfilaments and intermediate filaments, make up a cell's cytoskeleton.

mi′cro·tu′bu·lar adj.

microtubule

a hollow cylindrical structure (200 to 300 angstroms in diameter and of variable length) that occurs widely within plant and animal cells. Microtubules increase in number during cell division and are associated with the movement of deoxyribonucleic acid material. Compare microfilament.

microtubule

A cylindrical tube measuring 20–25 nm in diameter, composed of protofilaments which are in turn composed of alpha- and beta-tubulin polymers. Each microtubule is polarised: at one end (the negative (-) end), alpha-subunits are exposed; at the other end (the positive (+) end), beta-subunits are exposed. Microtubules act as a scaffolding to determine cell shape, and provide a matrix on which cell organelles and vesicles move, a process requiring motor proteins, including kinesin (which moves towards the (+) end of the microtubule) and dynein (which generally moves towards the (-) end). Microtubules also form the spindle fibres for separating chromosomes during mitosis.

mi·cro·tu·bule

(mī'krō-tū'byūl)
A cylindric cytoplasmic element that occurs widely in the cytoskeleton of plant and animal cells; microtubules increase in number during mitosis and meiosis, where they may be related to movement of the chromosomes or chromatids on the nuclear spindle during nuclear division.

microtubule

or

neurotubule

a hollow filament about 20–25 nm in diameter found in EUKARYOTE cells, composed of ACTIN-like protein called tubulin. Microtubules are thought to make up the CYTOSKELETON of the cell, the spindle fibres of MEIOSIS and MITOSIS, (See also COLCHICINE and, in some cells of plants and animals, form the 9 + 2 structure of the CILIUM and FLAGELLUM.

mi·cro·tu·bule

(mī'krō-tū'byūl)
A cylindric cytoplasmic element that occurs widely in the cytoskeleton of plant and animal cells; microtubules increase in number during mitosis and meiosis.

microtubule

(mī´krōtoo´būl),
n a hollow cylindrical structure that occurs widely within plant and animal cells. Microtubules increase in number during cell division and are associated with the movement of DNA material.

microtubule

any of the slender, tubular structures composed chiefly of tubulin, found in the cytoplasmic ground substance of nearly all cells; they are involved in maintenance of cell shape and in the movements of organelles and inclusions, and form the spindle fibers of mitosis.

microtubule-associated protein (MAP)
any of the high molecular weight proteins that bind to microtubules, enhancing polymerization.
microtubule-associated protein (MAP) kinase
a protein kinase that is activated in response to cell stimulation by many different growth factors and that mediates cellular responses by phosphorylating specific transcription factors and other target proteins.
microtubule organizing center (MTOC)
the location in a cell from which microtubules regrow after depolymerization. See also centrosome.
References in periodicals archive ?
1993) investigated the course of fertilization events in CB-treated Crassostrea gigas eggs using electron microscopy and immunofluorescent techniques for the observation of DNA and microtubule organization.
Treatment with UV-B radiation alone induced abnormal microtubule structures, including an asymmetric PPB, asymmetric spindle, and defective phragmoplast (Fig.
Cytokinesis in activated eggs is associated with ordered arrays of aligned microtubule bundles
2+] and cAMP on the flagellar movement of demembranated spermatozoa must result from the different types of regulations of microtubule sliding.
But certain fundamental data remain missing, particularly concerning the relationship between the amount of microtubules and the size and shape of spindles
A unique axial microtubule system (AMS) that forms in association with division of the plastid gives rise to the mitotic spindle (Brown & Lemmon, 1988b, 2011b; see also the section on hornworts).
Our direct comparison of epothilone binding and taxol binding in yeast tubulin can support development of novel natural and synthetic microtubule stabilizing agents with higher affinity for tubulin and lower sensitivity toward development of resistance of cancerous cells.
The efficacy of microtubule targeting agents (MTAs) has been validated by their successful use for the treatment of a wide variety of human cancers (Rosolen et al.
Microtubules extend down the length of axons--which transmit electrical signals in brain cells--serving as "superhighways of protein transfer," said Douglas Smith of the University of Pennsylvania in Philadelphia, who conducted the research with colleagues.
1994), and humans (Sathananthan, 1997) do not contain centrioles in meiotic centrosomes and do not display astral microtubule arrays.

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