Search results for "Actins"
showing 10 items of 153 documents
Evidence for the mechanosensor function of filamin in tissue development
2016
AbstractCells integrate mechanical properties of their surroundings to form multicellular, three-dimensional tissues of appropriate size and spatial organisation. Actin cytoskeleton-linked proteins such as talin, vinculin and filamin function as mechanosensors in cells, but it has yet to be tested whether the mechanosensitivity is important for their function in intact tissues. Here we tested, how filamin mechanosensing contributes to oogenesis in Drosophila. Mutations that require more or less force to open the mechanosensor region demonstrate that filamin mechanosensitivity is important for the maturation of actin-rich ring canals that are essential for Drosophila egg development. The ope…
Profilin 1 is required for abscission during late cytokinesis of chondrocytes
2009
Profilins are key factors for dynamic rearrangements of the actin cytoskeleton. However, the functions of profilins in differentiated mammalian cells are uncertain because profilin deficiency is early embryonic lethal for higher eukaryotes. To examine profilin function in chondrocytes, we disrupted the profilin 1 gene in cartilage (Col2pfn1). Homozygous Col2pfn1 mice develop progressive chondrodysplasia caused by disorganization of the growth plate and defective chondrocyte cytokinesis, indicated by the appearance of binucleated cells. Surprisingly, Col2pfn1 chondrocytes assemble and contract actomyosin rings normally during cell division; however, they display defects during late cytokines…
PCARE and WASF3 regulate ciliary F-actin assembly that is required for the initiation of photoreceptor outer segment disk formation
2020
Significance The photoreceptor outer segments are primary cilia, modified for phototransduction by incorporation of stacked opsin-loaded membrane disks that are continuously regenerated. This process is disrupted in several types of inherited retinal dystrophy, but the driving force remained unclear. We show that C2orf71/PCARE (photoreceptor cilium actin regulator), associated with inherited retinal dystrophy subtype RP54, efficiently recruits the Arp2/3 complex activator WASF3 to the cilium. This activates an actin dynamics-driven expansion of the ciliary tip, resembling membrane evagination in lamellipodia formation. Colocalization of this actin dynamics module to the base of the outer se…
Genotype-phenotype correlations in nemaline myopathy caused by mutations in the genes for nebulin and skeletal muscle alpha-actin.
2003
We present comparisons of the clinical pictures in a series of 60 patients with nemaline myopathy in whom mutations had been identified in the genes for nebulin or skeletal muscle alpha-actin. In the patients with nebulin mutations, the typical form of nemaline myopathy predominated, while severe, mild or intermediate forms were less frequent. Autosomal recessive inheritance had been verified or appeared likely in all nebulin cases. In the patients with actin mutations, the severe form of nemaline myopathy was the most common, but some had the mild or typical form, and a few showed other associated features such as intranuclear rods or actin accumulation. Most cases were sporadic, but in ad…
Modification of the rat aortic wall during ageing; possible relation with decrease of peptidergic innervation.
2002
Structural changes of the male rat aorta were followed from birth to old age in male and female rats. In males, the vessel media width and area progressively increase concomitantly with a decrease of nuclei density during ageing, suggesting an hypertrophy of the smooth muscle cells. These correlations were however not evidenced in females. TUNEL-positive cells were found in media of 4 and 6 months in both sexes, mainly on the luminal side and in the adventitia. When biochemical markers were investigated with immunohistochemistry, media was uniformly stained by the anti-vimentin and anti-alpha-smooth actin at all stages investigated. On the contrary, the surface of media stained with anti-de…
In vivo Trafficking and Localization of p24 Proteins in Plant Cells
2008
p24 proteins constitute a family of putative cargo receptors that traffic in the early secretory pathway. p24 proteins can be divided into four subfamilies (p23, p24, p25 and p26) by sequence homology. In contrast to mammals and yeast, most plant p24 proteins contain in their cytosolic C-terminus both a dilysine motif in the -3, -4 position and a diaromatic motif in the -7, -8 position. We have previously shown that the cytosolic tail of Arabidopsis p24 proteins has the ability to interact with ARF1 and coatomer (through the dilysine motif) and with COPII subunits (through the diaromatic motif). Here, we establish the localization and trafficking properties of an Arabidopsis thaliana p24 pr…
Myosin VIIa, harmonin and cadherin 23, three Usher I gene products that cooperate to shape the sensory hair cell bundle
2002
Deaf-blindness in three distinct genetic forms of Usher type I syndrome (USH1) is caused by defects in myosin VIIa, harmonin and cadherin 23. Despite being critical for hearing, the functions of these proteins in the inner ear remain elusive. Here we show that harmonin, a PDZ domain-containing protein, and cadherin 23 are both present in the growing stereocilia and that they bind to each other. Moreover, we demonstrate that harmonin b is an F-actin-bundling protein, which is thus likely to anchor cadherin 23 to the stereocilia microfilaments, thereby identifying a novel anchorage mode of the cadherins to the actin cytoskeleton. Moreover, harmonin b interacts directly with myosin VIIa, and i…
Aclidinium inhibits human lung fibroblast to myofibroblast transition
2011
Background Fibroblast to myofibroblast transition is believed to contribute to airway remodelling in lung diseases such as asthma and chronic obstructive pulmonary disease. This study examines the role of aclidinium, a new long-acting muscarinic antagonist, on human fibroblast to myofibroblast transition. Methods Human bronchial fibroblasts were stimulated with carbachol (10 −8 to 10 −5 M) or transforming growth factor-β1 (TGF-β1; 2 ng/ml) in the presence or absence of aclidinium (10 −9 to 10 −7 M) or different drug modulators for 48 h. Characterisation of myofibroblasts was performed by analysis of collagen type I and α-smooth muscle actin (α-SMA) mRNA and protein expression as well as α…
Transcriptional Differences between Diapausing and Non-Diapausing D. montana Females Reared under the Same Photoperiod and Temperature
2016
Background A wide range of insects living at higher latitudes enter diapause at the end of the warm season, which increases their chances of survival through harsh winter conditions. In this study we used RNA sequencing to identify genes involved in adult reproductive diapause in a northern fly species, Drosophila montana. Both diapausing and non-diapausing flies were reared under a critical day length and temperature, where about half of the emerging females enter diapause enabling us to eliminate the effects of varying environmental conditions on gene expression patterns of the two types of female flies. Results RNA sequencing revealed large differences between gene expression patterns of…
CD59 (homologous restriction factor 20), a plasma membrane protein that protects against complement C5b-9 attack, in human atherosclerotic lesions
1992
Blood cells express a cell membrane protein, termed homologous restriction factor 20 (HRF20) and identical to CD59, that can inhibit complement C5b-9 insertion into their membranes. In this report, we investigated by immunohistochemistry whether CD59 was present on cells in human atherosclerotic lesions since membranous C5b-9(m) has been found in lesions. Using a monoclonal anti-CD59 antibody, a cellular CD59 staining pattern was apparent in nearly all lesion specimens. CD59 stain co-localised with macrophage (CD14), T lymphocyte (CD7), endothelial cell (anti-factor VIII related antigen) and smooth muscle cell cytoskeletal-specific antigens (anti-alpha actin and muscle myosin). Endothelial …