Loss of a vimentin network due to gene disruption created viable mice that did not differ overtly from wild-type littermates. Here, primary fibroblasts derived vimentin-deficient (-/-) and (+/+) mouse embryos were cultured, biological functions studied in vitro systems resembling stress situations. Stiffness -/- was reduced by 40% comparison cells. Vimentin-deficient cells also displayed mechanical stability, motility directional migration towards different chemo-attractive stimuli....

Engulfment of particles by phagocytes is induced their interaction with specific receptors on the cell surface, which leads to actin polymerization and extension membrane protrusions form a closed phagosome. Membrane delivery from internal pools considered play an important role in pseudopod during phagocytosis. Here, we report that endogenous ADP ribosylation factor 6 (ARF6), small GTP-binding protein, undergoes sharp transient activation macrophages when phagocytosis was initiated via for...

Autophagy, an ancient and highly conserved intracellular degradation process, is viewed as a critical component of innate immunity because its ability to deliver cytosolic bacteria the lysosome. However, role bacterial autophagy in vivo remains poorly understood. The zebrafish (Danio rerio) has emerged vertebrate model for study infections it optically accessible at larval stages when immune system already functional. Here, we have characterized susceptibility larvae Shigella flexneri,...

The early control of potentially invading microbes by our immune system primarily depends on its main professional phagocytes – macrophages and neutrophils. Although the different functions these two cell types have been extensively studied, little is known about their respective contributions to initial microorganisms before onset adaptive responses. naturally translucent zebrafish larva has recently emerged as a powerful model vertebrate in which visualise dynamic interactions between...

Intermediate filaments (IFs) are a major component of the cytoskeleton in astrocytes. Their role is far from being completely understood. Immature astrocytes play neuronal migration and neuritogenesis, their IFs mainly composed vimentin. In mature differentiated astrocytes, vimentin replaced by IF protein glial fibrillary acidic (GFAP). response to injury CNS adult, become reactive, upregulate expression GFAP, reexpress These modifications contribute formation scar that obstructive axonal...

The intermediate filament vimentin might play a key role in vascular resistance to mechanical stress. We investigated the responses pressure (tensile stress) and flow (shear of mesenteric arteries perfused vitro from knockout mice. Arteries were isolated homozygous (Vim-/-, n = 14) or heterozygous vimentin-null mice (Vim+/-, 5) wild-type littermates (Vim+/+, 9). Passive arterial diameter (175+/-15 micron Vim+/+ at 100 mmHg) myogenic tone not affected by absence vimentin. Flow-induced (0-150...

Abstract Lymphocytes need rigidity while in circulation, but must abruptly become deformable to undergo transmigration into tissue. Previously, the control of leukocyte deformability has been attributed microfilaments or microtubules, present studies demonstrate greater importance vimentin intermediate filaments (IFs). In circulating T lymphocytes, IFs form a distinctive spherical cage that undergoes rapid condensation juxtanuclear aggregate during chemokine-induced polarization....

Glial fibrillary acidic protein (GFAP) is an intermediate filament expressed predominantly in astrocytes. The study of its expression the astrocyte lineage during development and reactive astrocytes has revealed intricate relationship with vimentin, another widely embryonic development. these findings suggested that vimentin could be implicated organization GFAP network. To address this question, we have examined network formation recently generated knockout (Vim-) mice. We show disrupted...

Onset of type I keratin 17 (K17) synthesis marks the adoption an appendageal fate within embryonic ectoderm, and its expression persists in specific cell types mature hair, glands, nail. We report that K17 null mice develop severe alopecia during first week postbirth, correlating with hair fragility, alterations follicular histology, apoptosis matrix cells. These are incompletely penetrant normalize starting postnatal cycle. Absence a phenotype correlates genetic strain-dependent...

Abstract —The endothelial cytoskeleton plays a key role in arterial responses to acute changes shear stress. We evaluated whether the intermediate filament protein vimentin is involved structural of arteries chronic blood flow (BF). In wild-type mice (V+/+) and vimentin-deficient (V−/−), left common carotid artery (LCA) was ligated near its bifurcation, 4 weeks later, structures occluded contralateral were compared with from sham-operated mice. Body weight mean BF did not differ between...

Vimentin belongs to the family of intermediate filament (IF) proteins. During nervous system development in mammals, it is transiently expressed precursor cells neuronal and glial lineages, then progressively replaced by other types IF Surprisingly, mice knock-out for vimentin develop reproduce without any apparent defects (Colucci-Guyon et al. Cell 79:679–694, 1994). In adult rodents, Bergmann glia (BG) cerebellum continue express together with fibrillary acidic protein (GFAP). A careful...

Mammalian genomes feature multiple genes encoding highly related keratin 6 (K6) isoforms. These type II keratins show a complex regulation with constitutive and inducible components in several stratified epithelia, including the oral mucosa skin. Two functional genes, K6α K6β, exist head-to-tail tandem array mouse genomes. We inactivated these two simultaneously via targeting homologous recombination. K6 null mice are viable initially indistinguishable from their littermates. Starting at to...

The progression of viral infections is notoriously difficult to follow in whole organisms. small, transparent zebrafish larva constitutes a valuable system study how pathogens spread. We describe here the course infection early larvae with heat-adapted variant Infectious Hematopoietic Necrosis Virus (IHNV), rhabdovirus that represents an important threat salmonid culture industry. When incubated at 24°C, permissive temperature for virus replication, infected by intravenous injection died...

Shigella flexneri, a Gram-negative enteroinvasive pathogen, causes inflammatory destruction of the human intestinal epithelium. Infection by S. flexneri has been well-studied in vitro and is paradigm for bacterial interactions with host immune system. Recent work revealed that components cytoskeleton have important functions innate immunity inflammation control. Septins, highly conserved cytoskeletal proteins, emerged as key players to infection, yet septin function vivo poorly understood....

Abstract Pten is one of the most frequently mutated tumour suppressor gene in cancer. PTEN generally altered invasive cancers such as glioblastomas, but its function collective cell migration and invasion not fully characterised. Herein, we report that loss increases speed during non-tumourous cells both vitro vivo. We further show promotes LKB1-dependent phosphorylation activation major metabolic regulator AMPK. In turn AMPK VASP phosphorylation, reduces localisation at cell-cell junctions...

Modulation of vascular tone by chemical and mechanical stimuli is a crucial adaptive phenomenon which involves cytoskeleton elements. Disruption, homologous recombination, the gene encoding vimentin, class III intermediate filament protein mainly expressed in cells, was reported to result apparently normal phenotype under physiological conditions. In this study, we evaluated whether lack vimentin affects adaptation pathological situations, such as reduction renal mass, condition usually...

Among vertebrate model species, the zebrafish embryo combines at an unprecedented level optical accessibility with easy genetic manipulation. As such, it is gaining recognition as a powerful to study innate immunity. In this chapter, we provide protocol for generation of embryos deficient in protein interest immune signaling using antisense morpholino oligonucleotides, systemic or local infection these bacteria, and assessment various aspects following response emphasis on microscopic...

Soluble N-ethyl maleimide-sensitive fusion protein attachment receptors (SNAREs) are core machinery for membrane during intracellular vesicular transport. Synaptosome-associated of 23 kDa (SNAP23) is a target SNARE previously identified at the plasma membrane, where it involved in exocytotic fusion. Here we show that SNAP23 associates with vimentin filaments Triton X-100 insoluble fraction fibroblasts primary culture and HeLa cells. Upon treatment human withN-ethyl-maleimide, dissociates...

Glial fibrillary acidic protein (GFAP), the principal intermediate filament (IF) of mature astrocytes in CNS, plays specific roles astrocyte functions. GFAP has multiple phosphorylation sites at its N-terminal head domain. To examine role these sites, we generated a series substitution mutant mice which (Ser/Thr) were replaced by Ala, different combinations.<i>Gfap</i>^{<i>hm3/hm3</i>} carrying substitutions all five showed extensive decrease both formation and amounts...

It has been reported that vimentin, a cytoskeleton filament is expressed only in mesenchymal cells after birth, re-expressed epithelial vivo under pathological conditions and vitro primary culture. Whether vimentin re-expression marker of cellular dedifferentiation or instrumental the maintenance cell structure and/or function matter debate. To address this issue, we used renal proximal tubular culture from vimentin-null mice (Vim-/-) wild-type littermates (Vim+/+). The absence did not...