Cytoskeleton structure

Glycophorin A is also considered to be involved in the binding of such important biological metal-ions as Ca " and Mg to the red-cell mem-brane. " This phenomenon may be important, because it has now been shown that glycophorin is a crucial component in the cytoplasmic, Ca -induced, morphological changes observed in red blood cells. This may result from the fact that glycophorin interacts with the proteins that create the red-cell, cytoskeleton structure. ... 

Keratins are insoluble proteins that make up such structures as hair, skin, nails, wool, and feathers and form the cytoskeleton structures in all cells of epithelial origin. Along with other fibrous proteins of the same dimensions (e.g., neurofilaments), keratin has been referred to as intermediary filament (IF). In the human being, keratin is one of the more abundant proteins. The basic keratin unit is a relatively small protein with a molecular weight of 40,000-70,000. About 20 different keratin polypeptides have been identified in human hair follicles, various epithelial cells, and tumor cells. They have been assigned numbers 1-20 and have been divided into two classes acidic (type 1) and neutral/base (type 2). A given tissue or cell line will have a characteristic keratin polypeptide distribution, as shown in Table 8.2. However, both types of peptides are always present in a given cell. 

Janmey, P.A., Xian, W. and Flanagan, L.A., 1999, Controlling cytoskeleton structure by phosphoinositide-protein interactions phosphoinositide binding protein domains and effects of lipid packing. Chem. Phys. Lipids 101 93-107. 

These vascular transport mechanisms within the hepa-tocytes require an intact cytoskeleton. This is because the transport of the membrane-encased vesicle keeps close to the cytoskeleton structures. 

It has been recently shown that YTX did not induce any effect in E-cadherin system in vivo [32]. These results confirm the loss of morphological changes the toxin induced in any internal organ after several days of oral treatment, which has been described earlier. Before these last results and from E-cadherin data, YTX was proposed to facilitate tumor spreading and metastasis formation [30] however, now affirmation of this hypothesis should be reviewed. In addition, an effect over E-cadherin levels was recently reported after azaspiracids exposition, suggesting that both toxins share their mechanism of action [33]. However, while human azaspiracids intoxications had been reported, YTX intoxications have never been described, and the data available about azaspiracid effect show a very different effect over cAMP, cytosolic calcium, intracellular pH, and cytoskeleton structure [34-39]. 

In addition to regulating organized tissue functions, E-, N-, and VE-cadherin-mediated intercellular contacts have been shown to suppress cell proliferation [24—26]. This phenomenon is thought to be a consequence of cadherin-induced alterations in the cytoskeleton structure [27], and to contribute to the abrogation of cell proliferation of confluent tissue cultures. 

Cardiac tissue engineering Better cell adhesion and mature cytoskeleton structure with well-defined periodic units in the contractile machinery (sarcomeres) in PLLA, superior response in PLLA, CM cell density was lower on hydrophilic and faster degrading electrospun scaffolds Zong et al. (2005)... 

Just how fast can proteins move in a biological membrane Many membrane proteins can move laterally across a membrane at a rate of a few microns per minute. On the other hand, some integral membrane proteins are much more restricted in their lateral movement, with diffusion rates of about 10 nm/sec or even slower. These latter proteins are often found to be anchored to the cytoskeleton (Chapter 17), a complex latticelike structure that maintains the cell s shape and assists in the controlled movement of various substances through the ceil. 

Interactions with the cytoskeleton seem to be responsible for the processing and the targeting of the Na+/fC+-ATPase to the appropriate compartment structures. Protein kinases are considered to play an essential role in modulation of the sodium pump. 

Role of the Cytoskeleton in Cell Division Formation of the Mitotic Spindle, Mitosis, and Cytokinesis Drug Effects on Microtubules Mlcrofllaments Actin Filaments Structure and Composition... 

As plant cells grow, they deposit new layers of cellulose external to the plasma membrane by exocytosis. The newest regions, which are laid down successively in three layers next to the plasma membrane, are termed the secondary cell wall. Because the latter varies in its chemical composition and structure at different locations around the cell, Golgi-derived vesicles must be guided by the cytoskeleton... 

More than 50 proteins have been discovered in the cytosol of nonmuscle cells that bind to actin and affect the assembly and disassembly of actin filaments or the cross-linking of actin filaments with each other, with other filamentous components of the cytoskeleton, or with the plasma membrane. Collectively, these are known as actin-binding proteins (ABPs). Their mechanisms of actions are complex and are subject to regulation by specific binding affinities to actin and other molecules, cooperation or competition with other ABPs, local changes in the concentrations of ions in the cytosol, and physical forces (Way and Weeds, 1990). Classifications of ABPs have been proposed that are based on their site of binding to actin and on their molecular structure and function (Pollard and Cooper, 1986 Herrmann, 1989 Pollard et al., 1994). These include the following ... 

In order to anticipate possible modes of regulation of cytoskeleton dynamics in vivo, it is necessary (a) to identify the kinetic intermediates involved in the polymerization process and to characterize their structural and functional properties and (b) to define the essential elementary steps in the hydrolysis process. 

Nonmuscle cells perform mechanical work, including self-propulsion, morphogenesis, cleavage, endocytosis, exocytosis, intracellular transport, and changing cell shape. These cellular functions are carried out by an extensive intracellular network of filamentous structures constimting the cytoskeleton. The cell cytoplasm is not a sac of fluid, as once thought. Essentially all eukaryotic cells contain three types of filamentous struc-mres actin filaments (7-9.5 nm in diameter also known as microfilaments), microtubules (25 nm), and intermediate filaments (10-12 nm). Each type of filament can be distinguished biochemically and by the electron microscope. 

An intracellular fibrous system exists of filaments with an axial periodicity of 21 nm and a diameter of 8-10 nm that is intermediate between that of microfilaments (6 nm) and microtubules (23 nm). Four classes of intermediate filaments are found, as indicated in Table 49-13. They are all elongated, fibrous molecules, with a central rod domain, an amino terminal head, and a carboxyl terminal tail. They form a structure like a rope, and the mature filaments are composed of tetramers packed together in a helical manner. They are important structural components of cells, and most are relatively stable components of the cytoskeleton, not undergoing rapid assembly and disassembly and not... 

Two major types of muscle fibers are found in humans white (anaerobic) and red (aerobic). The former are particularly used in sprints and the latter in prolonged aerobic exercise. During a sprint, muscle uses creatine phosphate and glycolysis as energy sources in the marathon, oxidation of fatty acids is of major importance during the later phases. Nonmuscle cells perform various types of mechanical work carried out by the structures constituting the cytoskeleton. These strucmres include actin filaments (microfilaments), micrombules (composed primarily of a- mbulin and p-mbulin), and intermediate filaments. The latter include keratins, vimentin-like proteins, neurofilaments, and lamins. 

P. Bonfante, At the interface between mycorrhizal fungi and plants. The structural organization of cell wall, plasma membrane, and cytoskeleton Mycota, Vol. IX, Fungal Associations (B. Hock, ed.). Springer-Verlag. In press. 

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