Microtubule-associated proteins differentiation

Isolated microtubules always contain small amounts of larger 300-kDa microtubule-associated proteins (MAPS).330 These elongated molecules may in part lie in the grooves between the tubulin subunits and in part be extended outward to form a low-density layer around the tubule.283 309 Nerve cells that contain stable microtubules have associated stabilizing proteins.331 A family of proteins formed by differential splicing of mRNA are known as tau. The tau proteins are prominent components of the cytoskeleton of neurons. They not only interact with microtubules but also undergo reversible phosphorylation. Hyperphosphorylated tau is the primary component of the paired helical filaments found in the brains of persons with Alzheimer disease.330... 

Francis F, Koulakoff A, Boucher D, Chafey P, Schaar B, Vinet MC, Friocourt G, McDonnell N, Reiner O, Kahn A, McConnell SK, Berwald-Netter Y, Denoulet P, Chelly J (1999) Dou-blecortin is a developmentally regulated, microtubule-associated protein expressed in migrating and differentiating neurons. Neuron 23 247-256... 

Gleeson JG, Lin PT, Flanagan LA, Walsh CA (1999) Doublecortin is a microtubule-associated protein and is expressed widely by migrating neurons. Neuron 23 257-271 Goldman SA, Nottebohm F (1983) Neuronal production, migration and differentiation in a vocal control nucleus of the adult female canary brain. Proc Natl Acad Sci USA 80 2390-2394... 

Burgoyne RD, Cumming R (1984) Ontogeny of microtubule-associated protein 2 in rat cerebellum Differential expression of the doublet polypeptides. Neuroscience 11 156-167. 

Caceres A, Binder LI, Payne MR, Bender P, Rebhun L, Steward O (1984) Differential subcellular localization of tubulin and the microtubule-associated protein MAP2 in brain tissue as revealed by immunocytochemistry with monoclonal hybridoma antibodies. J Neurosci 4 394-410. 

The medulloepithelioma looks like carcinoma but occurs in childhood, an unlikely age for carcinoma. The pseudostratified columnar epithelium of medulloepithe-iioma is crowded with cells that resemble those lining the embryonic neural tube. It rests on a type IV collagen basement membrane and fibrous stroma. The basal layer of the epithelium expresses nestin, vimentin, and microtubule-associated protein type 5 immunoreactiv-ity. Focal differentiation and expression of either GFAP, S-100 protein, NSE (Fig. 20.42), NF protein, CK, or EMA immunoreactivity frequently occur. 

Ohe conclusions suggested by the kinetic data obtained few years ago were that 1) the microtubule polymerization activity increases during brain development. This evolution seems to be related to the differential expxression of the microtubule-associated proteins, such as Tau proteins, differing in size and in polymerization activity 2) thyroid hormones increase the polymerization activity probably because they accelerate the transition fron the inmature to the more active mature Tau forms. However, little was knewn on the mechanism that generates Tau heterogeneity at different stages of brain development, and on the site of action of thyroid hormones. 

B. Riederer and A. Matus. Differential expression of distinct microtubule-associated proteins during brain development. Proc. Natl. Acad. Sd. USA 82 6006 (1985). 

D. Couchie, C. Pages, A.M. Bridoux, 6. Holland, M. Tarc and J. Nuimz. Microtubule-associated proteins and in vitro astrocyte differentiation. J. CeU Biol. 101 2095 (1985). 

For instance, Kerkis and collaborators detected the presence microtubule-associated proteins (MAPs), such as Lisl and Ndell, as neural markers at early stages of in vitro model for neuronal differentiation from pluripotent stem cells (Kerkis et al., 2011). 

The microtubule associated proteins (MAPs), Lisl and Ndell are involved in neuronal differentiation and cell migration during the CNS development. 

Microtubule-associated proteins (MAPs) are essential for neuronal differentiation and cell migration during the central nervous system (CNS) development and also in the adult nervous system In particular the distribution and role of lissencephaly (Lisl) and nuclear distribution element-like (Ndell) allows the comp>arison between neural differentiation in stem cells and during embryo development. They are very pwwerful tools not only due to... 

In interphase, microtubules are stabilized by several kinds of proteins that are found all along microtubules and are called MAPs. They tend to have repeating domains, which allow each MAP molecule to associate with more than one tubulin dimer. This produces a doubly effective method of controlling assembly, in that the conformations of several tubulin dimers may be individually stabilized and the stabilized subunits are also cross-linked. The binding of these structural MAPs is in turn controlled by kinases and phosphatases (Cassimeris and Spittle, 2001). During mitosis they are phosphorylated and detach from tubulin, whose assembly and disassembly comes under the control of proteins that operate more at the ends of microtubules. Differentiated cells, such as neurons, do not divide. However, as microtubules and MAPs are slowly transported along axons (Baas and Buster, 2004), the MAPs maybe phosphorylated in particular places, at times when structural plasticity is required for making synapses or other contacts. 

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