Microtubule-associated distribution

Schoenfeld, T. A. and Obar, R. A. Diverse distribution and function of fibrous microtubule-associated proteins in the nervous system. Int. Rev. Cytol. 151 67-137,1994. 

Janke, C., Holzer, M., Klose, J, and Arendt, T. (1996) Distribution of isoforms of the microtubule-associated protein tau in grey and white matter areas of human brain a two-dimensional gelelectrophoretic analysis. FEBS Lett. 379, 222-226. 

NFTs are the second most important pathological feature of AD. These consist of paired helical filaments that are abnormal aggregates of abnormally folded, or hyperphosphorylated, forms of the microtubule associated tau protein. The progressive increase in the distribution of NFTs throughout many regions of the brain is related to the stages in the development of the disease. Thus the NFTs first appear in the entorhinal... 

Comea-Hebert V, Watkins KC, Roth BL, et al. Similar ultrastructural distribution of the 5-HT(2A) serotonin receptor and microtubule-associated protein MAP1A in cortical dendrites of adult rat. Neuroscience 2002 113 23-35. 

De Camilli P, Miller PE, Navone F, Theurkauf WE, VaUee RB (1984) Distribution of microtubule-associated protein 2 in the nervous system of the rat studied by immunofluorescence. Neuroscience 11 817-846. 

Neely MD, Boekelheide K. 1988. Sertoli cell processes have axoplasmic features an ordered microtubule distribution and an abundant high molecular weight microtubule-associated protein (cytoplasmic dynein). J. Cell Biol. 107 1767-76... 

Dotti CG, Banker GA, Binder LI (1987) The expression and distribution of the microtubule-associated proteins tau and microtubule-associated protein 2 in hippocampal neurons in the rat in situ and in cell culture. Neuroscience 23 121-130... 

A large number of proteins influence the assembly and stability of microtubules and their association with other cell structures (Table 20-1). These proteins are collectively called microtubule-associated proteins (MAPs) because most co purify with microtubules isolated from cells. The results of Immunofluorescence localization studies also have shown a parallel distribution of MAPs and microtubules in cells— strong evidence for their interaction In vivo. 

Microtubules are cytoskeletal polymers consisting of repeatii a/ -tubulin heterodimers and a variety of minor components known as microtubule-associated proteins which are important for the regulation and distribution of microtubules in the cell Microtubules play the key role in many vital cellular aaivities such as mitosis, intracellular vesicle tnmsport, o miza-tion and positioning of membranous organelles, and determination of cell shape and motility. 

In short, all these data suggest that disruption of interactions between CPT I and cytoskeletal component(s) may de-inhibit CPT I and, therefore, increase enzyme activity. This is in line with the current notion that the dynamics and intracellular distribution of mitochondria in living cells may result from specific interactions of mitochondria with components of the cytoskeleton. In the case of rat-brain mitochondria, accruing evidence indicates that specific interactions occur between mitochondrial-outer-membrane proteins and cytoskeletal proteins. A well described example being the interaction between porin, microtubule-associated protein 2, and the neurofilamental proteins NF-H and NF-M. The existence of direct contact sites between intermediate filaments and the mitochondrial outer membrane has been reported not only in neurons, but also in smooth muscle myocytes and adrenal cortex cells. As far as we know, although rat-liver mitochondria have been shown to interact with microtubules, direct evidence for their interaction with intermediate filaments is still lacking. 

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... 

Akner G, Wikstrom AC, Gustafsson JA (1995) Subcellular distribution of the glucocorticoid receptor and evidence for its association with microtubules J Steroid Biochem Mol Biol 52 1... 

The principal cytoskeletal proteins in non-muscle cells are actin, tubulin, and the components of intermediate filaments. Actin can exist either as monomers ( G-actin ) or polymerized into 70 A diameter double filament ( F-actin ). Polymerized actin usually is localized at the margins of the cells, linked by other proteins to the cell membrane. In contrast, tubulin forms hollow filaments, approximately 250 A in diameter, that are distributed within a cell in association, generally, with cell organelles. Stabilized microtubule structures are found in the flagella and cilia of eucaryotic cells however, in other instances - examples being the mitotic apparatus and the cytoskeletal elements arising in directed cell locomotion - the microtubules are temporal entities. Intermediate filaments, which are composed of keratin-like proteins, are approximately 100 A thick and form stable structural elements that impart rigidity, for example, to nerve axons and epithelial cells. 

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