Filament attachment

Another actin binding protein, the large 100 kDa a-actinin, crosslinks actin filaments together at the dense bodies and near the points of actin filament attachment to the cell membranes, a-actinin is also associated with still another actin binding protein, vinculin, which may stabilize both the Z-line like dense bodies and the membrane attachments. 

Desmin Lies alongside actin filaments Attaches to plasma membrane (plasma-lemma). 

The Concentric Retriever (Concentric Medical Inc., Mountain View, CA), a flexible, nitinol wire with helical tapering coil loops (X5 and X6) that is used in conjunction with a balloon guide catheter (8 or 9 French) and a microcatheter, is the only device currently approved by the FDA for the endovascular treatment of stroke patients (Fig. 4.3). The second-generation devices (L5 and L6) differ from the X devices by the inclusion of a system of arcading filaments attached to a nontapering... 

F -ATPase Driven Nanomotors. Another type of biological driven engine is that of Fi-adenosine triphosphate synthease (Fi-ATPase) which hydrolyzes the ATP in the surrounding medium. Kinosita Jr. et al. observed the rotation of an actin filament attached to the Fi - ATPase motor. Later, Montemagno followed with the incorporation of a nickel nanorod with the Fi-ATPase motor. The outcome was the rotation of the... 

Georgatos, S. D., and Blobel, G. (1987a). Lamin B constitutes an intermediate filament attachment site at the nuclear envelope./. Biol. Chem. 105, 117-125. 

Cytoskeleton— A network of assorted protein filaments attached to the cell membrane and to various organelles that makes up the framework for cell shape and movement. 

El ater.—An elastic spral filament attached to the spores of some Liverworts and Horsetails and aiding in their dispersal when mature. 

Wilkins and Lin (1982) claimed that vinculin is an actin capping protein. However, highly purified preparations of vinculin do not have such a capping action at all (Evans et al., 1984). It has also been reported that such a purified vinculin does not bundle actin filaments either (Ohtaki et al, 1986). Therefore, it is likely that some proteins other than vinculin are needed to make actin filaments attach to the cell membrane. 

The Z lines arrange actin filaments in register and segment the myofibrils into the structural unit, the sarcomere. Electron microscopy shows a highly organized tetragonal lattice structure to which actin filaments attach. 

The desmosomal junction is a morphological entity that is very distinct from adherence junctions involving classical cadherins [44]. The plasma membrane domains of apposing cells are separated by a 20-30 nm thick layer, which in cross section in electron micrographs reveals a midline structure and electron-dense threads stretching laterally from the midline back to the plasma membrane. The cytoplasmic face of each membrane domain is covered with an electron-dense plaque to which bundles of intermediate filaments attach, rather than the actin filaments present in adherence junctions containing classical cadherins. In most epithelia the intermediate filaments are based on keratins but rarer examples of desmosomal junctions coupled into intermediate filaments of the vimentin or desmin type are known [5]. 

The cytoskeleton, found in both animal and plant cells, is composed of protein filaments attached to the plasma membrane and organelles. They provide a framework for the cell and aid in cell movement. They constantly change shape and move about. Three types of fibers make up the cytoskeleton ... 

Figure 8.42. Actin filament attached to the y-rotor by streptavidin and Fi-ATPase fixed on substrate. ATP drives counter clockwise rotation of the actin filament in 120° steps, which are directly observed by video microscope. - (Reprinted with permission...

Axial filament A subsurface filament attached near the ends of the cytoplasmic cylinder of spirochetes that causes the spirochete body to rotate like a corkscrew. Also known as endoflagellum. 

Fig. 8.6. Standard Westinghouse electrode transition tip, showing two methods of filament attachment (Shapiro, Z. M. Ref. 7.

Talin is a large molecule (270 kDa). Below 0.7 mg/ml it exists as a monomer. Above this concentration it begins to self-associate to form dimers (Molony et al. 1987). In many types of cultured cells, talin in concentrated in focal adhesions (Bur-ridge and Cornell 1983), regions where bundles of actin filaments attach to the cytoplasnuc face of the membrane and where the external face of the membrane adheres most tightly to the underlying substratum. Talin is also found in ruffling membranes and subjacent the bundles of extracellular matrix on the cell surface (Collier et al. 1982). 

Z disks Zigzag protein structures to which thin filaments attach. A sarcomere is made up of two Z disks and the thin filaments attached to them. 

Linear and branched polymerization of actin filaments attached to the plasma membrane, or to internal components, is associated with ATP hydrolysis that... 

---