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Intermediate filaments dimer structure

Strelkov, S. V., Herrmann, H., Geisler, N., Wedig, T., Zimbelmann, R., Aebi, U., and Burkhard, P. (2002). Conserved segments 1A and 2B of the intermediate filament dimer Their atomic structures and role in filament assembly. EMBO J. 21, 1255-1266. [Pg.142]

The components of the intermediate filaments belong to five related protein families. They are specific for particular cell types. Typical representatives include the cytokeratins, desmin, vimentin, glial fibrillary acidic protein (GFAP), and neurofilament. These proteins all have a rod-shaped basic structure in the center, which is known as a superhelix ( coiled coil see keratin, p. 70). The dimers are arranged in an antiparallel fashion to form tet-ramers. A staggered head-to-head arrangement produces protofilaments. Eight protofilaments ultimately form an intermediary filament. [Pg.204]

Figure 7-31 A model for the structure of keratin microfibrils of intermediate filaments. (A) A coiled-coil dimer, 45-nm in length. The helical segments of the rod domains are interrupted by three linker regions. The conformations of the head and tail domains are unknown but are thought to be flexible. (B) Probable organization of a protofilament, involving staggered antiparallel rows of dimers. From Jeffrey A. Cohlberg297... Figure 7-31 A model for the structure of keratin microfibrils of intermediate filaments. (A) A coiled-coil dimer, 45-nm in length. The helical segments of the rod domains are interrupted by three linker regions. The conformations of the head and tail domains are unknown but are thought to be flexible. (B) Probable organization of a protofilament, involving staggered antiparallel rows of dimers. From Jeffrey A. Cohlberg297...
The two-stranded a-helical coiled coil is now recognized as one of natures favorite ways of creating a dimerization motif and has been predicted to occur in a diverse group of over 200 proteins.111 This structure consists of two amphipathic, right-handed a-helices that adopt a left-handed supercoil, analogous to a two-stranded rope where the nonpolar face of each a-helix is continually adjacent to that of the other helix. 2 This structure was first postulated by Crick to explain the X-ray diffraction pattern of a-keratin in the absence of sequence information.Pl The coiled-coil dimerization motif is natures way of creating a rod-like molecule that perhaps plays only a structural role in many fibrous proteins, such as the kmef (keratin, myosin, epidermis, fibrinogen) class 3,4 and the intermediate filament proteins)5 6 ... [Pg.68]

Together with actin microfilaments and microtubules, keratin filaments make up the cytoskeleton of vertebrate epithelial cells. Keratins belong to a family of intermediate filament proteins that form a-helical coiled-coil dimers that associate laterally and end to end to form 10 nm diameter filaments. Keratin and actin filaments and microtubules form an integrated cytoskeleton that preserves the shape and structural integrity of the ker-atinocyte as well as serves to transmit mechanical loads. Keratins account for about 30% of the total protein in basal cells. [Pg.89]

Fig. 10.28. Formation of a cytokeratin filament. The central rod of the keratin monomer is principally a-helical structure. A specific acidic keratin monomer combines with a specific basic keratin monomer to form a heterodimer coil (a coiled coil structure). Two dimers combine in antiparallel fashion to form a tetramer, and the tetramers combine head-to-tail to form pro to filaments. Approximately eight protofilaments combine to form a filament. The filament is thicker than actin filaments (called thin filaments or micro filaments) and thinner than microtubules (thick tubes) and is therefore called an intermediate filament. Fig. 10.28. Formation of a cytokeratin filament. The central rod of the keratin monomer is principally a-helical structure. A specific acidic keratin monomer combines with a specific basic keratin monomer to form a heterodimer coil (a coiled coil structure). Two dimers combine in antiparallel fashion to form a tetramer, and the tetramers combine head-to-tail to form pro to filaments. Approximately eight protofilaments combine to form a filament. The filament is thicker than actin filaments (called thin filaments or micro filaments) and thinner than microtubules (thick tubes) and is therefore called an intermediate filament.
Figure 1-33. Schematic Ulustratiug the structure of an intermediate filament protein chain (type I-type II dimer). E are the end domains (E2 the C terminus and Ei the N terminus), V is a variable sequence region, and H is a high sequence region. Figure 1-33. Schematic Ulustratiug the structure of an intermediate filament protein chain (type I-type II dimer). E are the end domains (E2 the C terminus and Ei the N terminus), V is a variable sequence region, and H is a high sequence region.
These dimers aggregate in an antiparallel arrangement to form structural units composed of four protein chains or tetramers [101,102], Seven to ten of these tetramer units are then believed to combine or aggregate into a larger helical structure, forming the intermediate filaments (the microfibril structures) of animal hairs. [Pg.41]

Although various primary proteins form a variety of intermediate filaments, aU intermediate filaments have a similar structural design. The basic building block, a monomer of IF protein, is a long central a-helix, called rod domain, interrupted by linkers and flanked by an N-terminal head and a C-terminal tail domain as shown in Fig. 3a [49, 55, 56]. Two monomers twist around each other to form a coUed-coil dimer, which is stabilized by a hydrophobic left-handed stripe that winds around the axis of each a-helrx [57], This rod-Uke domain controls the mechanical property of the single intermediate filament. Despite these similarities, there are distinct differences at the tail domain between nuclear IF proteins (e.g., lamin) and cytoplasmic IF proteins (e.g., vimentin) [58]. [Pg.327]


See other pages where Intermediate filaments dimer structure is mentioned: [Pg.868]    [Pg.9]    [Pg.125]    [Pg.362]    [Pg.362]    [Pg.326]    [Pg.808]    [Pg.180]    [Pg.40]    [Pg.329]    [Pg.376]    [Pg.122]    [Pg.539]    [Pg.590]    [Pg.286]    [Pg.287]    [Pg.61]   
See also in sourсe #XX -- [ Pg.40 ]




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