scholarly journals Properties of Intermediate Filament Networks Assembled from Keratin 8 and 18 in the Presence of Mg2+

2012 ◽  
Vol 103 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Anke Leitner ◽  
Tobias Paust ◽  
Othmar Marti ◽  
Paul Walther ◽  
Harald Herrmann ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Keratin 8 ◽  
Filament Networks

Paranemin and the organization of desmin filament networks

2001 ◽  
Vol 114 (6) ◽  
pp. 1079-1089 ◽  
Author(s):  
S.C. Schweitzer ◽  
M.W. Klymkowsky ◽  
R.M. Bellin ◽  
R.M. Robson ◽  
Y. Capetanaki ◽  
...  
Keyword(s):  
Cell Lines ◽  
Intermediate Filament ◽  
Transgene Expression ◽  
De Novo ◽  
Muscle Cells ◽  
The Other ◽  
Intermediate Filament Proteins ◽  
Mouse Fibroblasts ◽  
Filament Networks ◽  
Filament Network

De novo expression of vimentin, GFAP or peripherin leads to the assembly of an extended intermediate filament network in intermediate filament-free SW13/cl.2 cells. Desmin, in contrast, does not form extended filament networks in either SW13/cl.2 or intermediate filament-free mouse fibroblasts. Rather, desmin formed short thickened filamentous structures and prominent spot-like cytoplasmic aggregates that were composed of densely packed 9–11 nm diameter filaments. Analysis of stably transfected cell lines indicates that the inability of desmin to form extended networks is not due to a difference in the level of transgene expression. Nestin, paranemin and synemin are large intermediate filament proteins that coassemble with desmin in muscle cells. Although each of these large intermediate filament proteins colocalized with desmin when coexpressed in SW-13 cells, expression of paranemin, but not synemin or nestin, led to the formation of an extended desmin network. A similar rescue of desmin network organization was observed when desmin was coexpressed with vimentin, which coassembles with desmin, or with keratins, which formed a distinct filament network. These studies demonstrate that desmin filaments differ in their organizational properties from the other vimentin-like intermediate filament proteins and appear to depend upon coassembly with paranemin, at least when they are expressed in non-muscle cells, in order to form an extended filament network.

scholarly journals The association of prosomes with some of the intermediate filament networks of the animal cell.

1988 ◽  
Vol 107 (4) ◽  
pp. 1517-1530 ◽  
Author(s):  
M F Grossi de Sa ◽  
C Martins de Sa ◽  
F Harper ◽  
M Olink-Coux ◽  
M Huesca ◽  
...  
Keyword(s):  
Immunoelectron Microscopy ◽  
Intermediate Filament ◽  
Biochemical Composition ◽  
Animal Cell ◽  
Filament Networks ◽  
Filament Network

The small RNP complexes of defined morphology and biochemical composition termed prosomes, first isolated from the cytoplasm associated with repressed mRNA (Martins de Sa, C., M.-F. Grossi de Sa, O. Akhayat, F. Broders, and K. Scherrer. J. Mol. Biol. 1986. 187:47-493), were found also in the nucleus (Grossi de Sa, M.-F., C. Martins de Sa, F. Harper, O. Coux, O. Akhayat, P. Gounon, J. K. Pal, Y. Florentin, and K. Scherrer. 1988. J. Cell Sci. 89:151-165). Immunofluorescence, immunoelectron microscopy, and immunochemical studies using mAbs directed against some of the prosomal proteins of duck erythroblasts indicate that in the cytoplasm of HeLa and PtK cells, prosome antigens are associated with the intermediate filament network of the cytokeratin type.

scholarly journals Stiffening and inelastic fluidization in vimentin intermediate filament networks

Soft Matter ◽  
2019 ◽  
Vol 15 (36) ◽  
pp. 7127-7136 ◽  
Author(s):  
Anders Aufderhorst-Roberts ◽  
Gijsje H. Koenderink
Keyword(s):  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Shear Rheology ◽  
Cellular Processes ◽  
Filament Networks ◽  
Nonlinear Shear ◽  
Vimentin Intermediate Filament

Nonlinear shear rheology reveals that intermediate filaments balance two contradictory roles: mechanoprotection by stiffening and dynamic cellular processes through softening.

scholarly journals Deletions in epidermal keratins leading to alterations in filament organization in vivo and in intermediate filament assembly in vitro.

1990 ◽  
Vol 111 (6) ◽  
pp. 3049-3064 ◽  
Author(s):  
P A Coulombe ◽  
Y M Chan ◽  
K Albers ◽  
E Fuchs
Keyword(s):  
Intermediate Filament ◽  
Intermediate Filament Proteins ◽  
Amino Terminal ◽  
Filament Assembly ◽  
Keratin Filaments ◽  
Keratin Filament ◽  
Filament Networks ◽  
10 Nm Filaments

To investigate the sequences important for assembly of keratins into 10-nm filaments, we used a combined approach of (a) transfection of mutant keratin cDNAs into epithelial cells in vivo, and (b) in vitro assembly of mutant and wild-type keratins. Keratin K14 mutants missing the nonhelical carboxy- and amino-terminal domains not only integrated without perturbation into endogenous keratin filament networks in vivo, but they also formed 10-nm filaments with K5 in vitro. Surprisingly, keratin mutants missing the highly conserved L L E G E sequence, common to all intermediate filament proteins and found at the carboxy end of the alpha-helical rod domain, also assembled into filaments with only a somewhat reduced efficiency. Even a carboxy K14 mutant missing approximately 10% of the rod assembled into filaments, although in this case filaments aggregated significantly. Despite the ability of these mutants to form filaments in vitro, they often perturbed keratin filament organization in vivo. In contrast, small truncations in the amino-terminal end of the rod domain more severely disrupted the filament assembly process in vitro as well as in vivo, and in particular restricted elongation. For both carboxy and amino rod deletions, the more extensive the deletion, the more severe the phenotype. Surprisingly, while elongation could be almost quantitatively blocked with large mutations, tetramer formation and higher ordered lateral interactions still occurred. Collectively, our in vitro data (a) provide a molecular basis for the dominance of our mutants in vivo, (b) offer new insights as to why different mutants may generate different phenotypes in vivo, and (c) delineate the limit sequences necessary for K14 to both incorporate properly into a preexisting keratin filament network in vivo and assemble efficiently into 10-nm keratin filaments in vitro.

scholarly journals A rim-and-spoke hypothesis to explain the biomechanical roles for cytoplasmic intermediate filament networks

2017 ◽  
Vol 130 (20) ◽  
pp. 3437-3445 ◽  
Author(s):  
Roy A. Quinlan ◽  
Nicole Schwarz ◽  
Reinhard Windoffer ◽  
Christine Richardson ◽  
Tim Hawkins ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Filament Networks

scholarly journals Rapid Movements of Vimentin on Microtubule Tracks: Kinesin-dependent Assembly of Intermediate Filament Networks

1998 ◽  
Vol 143 (1) ◽  
pp. 159-170 ◽  
Author(s):  
Veena Prahlad ◽  
Miri Yoon ◽  
Robert D. Moir ◽  
Ronald D. Vale ◽  
Robert D. Goldman
Keyword(s):  
Green Fluorescent Protein ◽  
Indirect Immunofluorescence ◽  
Intermediate Filament ◽  
Fluorescent Protein ◽  
Model System ◽  
Local Regulation ◽  
Filament Networks ◽  
Conventional Kinesin ◽  
Green Fluorescent ◽  
Membranous Protein

The assembly and maintenance of an extended intermediate filament (IF) network in fibroblasts requires microtubule (MT) integrity. Using a green fluorescent protein–vimentin construct, and spreading BHK-21 cells as a model system to study IF–MT interactions, we have discovered a novel mechanism involved in the assembly of the vimentin IF cytoskeleton. This entails the rapid, discontinuous, and MT-dependent movement of IF precursors towards the peripheral regions of the cytoplasm where they appear to assemble into short fibrils. These precursors, or vimentin dots, move at speeds averaging 0.55 ± 0.24 μm/s. The vimentin dots colocalize with MT and their motility is inhibited after treatment with nocodazole. Our studies further implicate a conventional kinesin in the movement of the vimentin dots. The dots colocalize with conventional kinesin as shown by indirect immunofluorescence, and IF preparations from spreading cells are enriched in kinesin. Furthermore, microinjection of kinesin antibodies into spreading cells prevents the assembly of an extended IF network. These studies provide insights into the interactions between the IF and MT systems. They also suggest a role for conventional kinesin in the distribution of non-membranous protein cargo, and the local regulation of IF assembly.

scholarly journals Heat Shock Proteins Regulate Structure of Intermediate Filament Networks

2012 ◽  
Vol 102 (3) ◽  
pp. 696a
Author(s):  
Jona Kayser ◽  
Martin Haslbeck ◽  
Harald Herrmann ◽  
Johannes Buchner ◽  
Andreas R. Bausch
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Intermediate Filament ◽  
Filament Networks ◽  
Shock Proteins
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